1.16. Stateless Codec Control Reference

The Stateless Codec control class is intended to support stateless decoder and encoders (i.e. hardware accelerators).

These drivers are typically supported by the Memory-to-memory Stateless Video Decoder Interface, and deal with parsed pixel formats such as V4L2_PIX_FMT_H264_SLICE.

1.16.1. Stateless Codec Control ID

V4L2_CID_CODEC_STATELESS_CLASS (class)

The Stateless Codec class descriptor.

V4L2_CID_STATELESS_H264_SPS (struct)

Specifies the sequence parameter set (as extracted from the bitstream) for the associated H264 slice data. This includes the necessary parameters for configuring a stateless hardware decoding pipeline for H264. The bitstream parameters are defined according to ITU-T Rec. H.264 Specification (04/2017 Edition), section 7.4.2.1.1 “Sequence Parameter Set Data Semantics”. For further documentation, refer to the above specification, unless there is an explicit comment stating otherwise.

type v4l2_ctrl_h264_sps

struct v4l2_ctrl_h264_sps

__u8	profile_idc
__u8	constraint_set_flags	See Sequence Parameter Set Constraints Set Flags
__u8	level_idc
__u8	seq_parameter_set_id
__u8	chroma_format_idc
__u8	bit_depth_luma_minus8
__u8	bit_depth_chroma_minus8
__u8	log2_max_frame_num_minus4
__u8	pic_order_cnt_type
__u8	log2_max_pic_order_cnt_lsb_minus4
__u8	max_num_ref_frames
__u8	num_ref_frames_in_pic_order_cnt_cycle
__s32	offset_for_ref_frame[255]
__s32	offset_for_non_ref_pic
__s32	offset_for_top_to_bottom_field
__u16	pic_width_in_mbs_minus1
__u16	pic_height_in_map_units_minus1
__u32	flags	See Sequence Parameter Set Flags

Sequence Parameter Set Constraints Set Flags

V4L2_H264_SPS_CONSTRAINT_SET0_FLAG	0x00000001
V4L2_H264_SPS_CONSTRAINT_SET1_FLAG	0x00000002
V4L2_H264_SPS_CONSTRAINT_SET2_FLAG	0x00000004
V4L2_H264_SPS_CONSTRAINT_SET3_FLAG	0x00000008
V4L2_H264_SPS_CONSTRAINT_SET4_FLAG	0x00000010
V4L2_H264_SPS_CONSTRAINT_SET5_FLAG	0x00000020

Sequence Parameter Set Flags

V4L2_H264_SPS_FLAG_SEPARATE_COLOUR_PLANE	0x00000001
V4L2_H264_SPS_FLAG_QPPRIME_Y_ZERO_TRANSFORM_BYPASS	0x00000002
V4L2_H264_SPS_FLAG_DELTA_PIC_ORDER_ALWAYS_ZERO	0x00000004
V4L2_H264_SPS_FLAG_GAPS_IN_FRAME_NUM_VALUE_ALLOWED	0x00000008
V4L2_H264_SPS_FLAG_FRAME_MBS_ONLY	0x00000010
V4L2_H264_SPS_FLAG_MB_ADAPTIVE_FRAME_FIELD	0x00000020
V4L2_H264_SPS_FLAG_DIRECT_8X8_INFERENCE	0x00000040

V4L2_CID_STATELESS_H264_PPS (struct)

Specifies the picture parameter set (as extracted from the bitstream) for the associated H264 slice data. This includes the necessary parameters for configuring a stateless hardware decoding pipeline for H264. The bitstream parameters are defined according to ITU-T Rec. H.264 Specification (04/2017 Edition), section 7.4.2.2 “Picture Parameter Set RBSP Semantics”. For further documentation, refer to the above specification, unless there is an explicit comment stating otherwise.

type v4l2_ctrl_h264_pps

struct v4l2_ctrl_h264_pps

__u8	pic_parameter_set_id
__u8	seq_parameter_set_id
__u8	num_slice_groups_minus1
__u8	num_ref_idx_l0_default_active_minus1
__u8	num_ref_idx_l1_default_active_minus1
__u8	weighted_bipred_idc
__s8	pic_init_qp_minus26
__s8	pic_init_qs_minus26
__s8	chroma_qp_index_offset
__s8	second_chroma_qp_index_offset
__u16	flags	See Picture Parameter Set Flags

Picture Parameter Set Flags

V4L2_H264_PPS_FLAG_ENTROPY_CODING_MODE	0x0001
V4L2_H264_PPS_FLAG_BOTTOM_FIELD_PIC_ORDER_IN_FRAME_PRESENT	0x0002
V4L2_H264_PPS_FLAG_WEIGHTED_PRED	0x0004
V4L2_H264_PPS_FLAG_DEBLOCKING_FILTER_CONTROL_PRESENT	0x0008
V4L2_H264_PPS_FLAG_CONSTRAINED_INTRA_PRED	0x0010
V4L2_H264_PPS_FLAG_REDUNDANT_PIC_CNT_PRESENT	0x0020
V4L2_H264_PPS_FLAG_TRANSFORM_8X8_MODE	0x0040
V4L2_H264_PPS_FLAG_SCALING_MATRIX_PRESENT	0x0080	V4L2_CID_STATELESS_H264_SCALING_MATRIX must be used for this picture.

V4L2_CID_STATELESS_H264_SCALING_MATRIX (struct)

Specifies the scaling matrix (as extracted from the bitstream) for the associated H264 slice data. The bitstream parameters are defined according to ITU-T Rec. H.264 Specification (04/2017 Edition), section 7.4.2.1.1.1 “Scaling List Semantics”. For further documentation, refer to the above specification, unless there is an explicit comment stating otherwise.

type v4l2_ctrl_h264_scaling_matrix

struct v4l2_ctrl_h264_scaling_matrix

__u8	scaling_list_4x4[6][16]	Scaling matrix after applying the inverse scanning process. Expected list order is Intra Y, Intra Cb, Intra Cr, Inter Y, Inter Cb, Inter Cr. The values on each scaling list are expected in raster scan order.
__u8	scaling_list_8x8[6][64]	Scaling matrix after applying the inverse scanning process. Expected list order is Intra Y, Inter Y, Intra Cb, Inter Cb, Intra Cr, Inter Cr. The values on each scaling list are expected in raster scan order.

V4L2_CID_STATELESS_H264_SLICE_PARAMS (struct)

Specifies the slice parameters (as extracted from the bitstream) for the associated H264 slice data. This includes the necessary parameters for configuring a stateless hardware decoding pipeline for H264. The bitstream parameters are defined according to ITU-T Rec. H.264 Specification (04/2017 Edition), section 7.4.3 “Slice Header Semantics”. For further documentation, refer to the above specification, unless there is an explicit comment stating otherwise.

type v4l2_ctrl_h264_slice_params

struct v4l2_ctrl_h264_slice_params

__u32	header_bit_size	Offset in bits to slice_data() from the beginning of this slice.
__u32	first_mb_in_slice
__u8	slice_type
__u8	colour_plane_id
__u8	redundant_pic_cnt
__u8	cabac_init_idc
__s8	slice_qp_delta
__s8	slice_qs_delta
__u8	disable_deblocking_filter_idc
__s8	slice_alpha_c0_offset_div2
__s8	slice_beta_offset_div2
__u8	num_ref_idx_l0_active_minus1	If num_ref_idx_active_override_flag is not set, this field must be set to the value of num_ref_idx_l0_default_active_minus1
__u8	num_ref_idx_l1_active_minus1	If num_ref_idx_active_override_flag is not set, this field must be set to the value of num_ref_idx_l1_default_active_minus1
__u8	reserved	Applications and drivers must set this to zero.
struct v4l2_h264_reference	ref_pic_list0[32]	Reference picture list after applying the per-slice modifications
struct v4l2_h264_reference	ref_pic_list1[32]	Reference picture list after applying the per-slice modifications
__u32	flags	See Slice Parameter Flags

Slice Parameter Set Flags

V4L2_H264_SLICE_FLAG_DIRECT_SPATIAL_MV_PRED	0x00000001
V4L2_H264_SLICE_FLAG_SP_FOR_SWITCH	0x00000002

V4L2_CID_STATELESS_H264_PRED_WEIGHTS (struct)

Prediction weight table defined according to ITU-T Rec. H.264 Specification (04/2017 Edition), section 7.4.3.2 “Prediction Weight Table Semantics”. The prediction weight table must be passed by applications under the conditions explained in section 7.3.3 “Slice header syntax”.

type v4l2_ctrl_h264_pred_weights

struct v4l2_ctrl_h264_pred_weights

__u16	luma_log2_weight_denom
__u16	chroma_log2_weight_denom
struct v4l2_h264_weight_factors	weight_factors[2]	The weight factors at index 0 are the weight factors for the reference list 0, the one at index 1 for the reference list 1.

type v4l2_h264_weight_factors

struct v4l2_h264_weight_factors

__s16	luma_weight[32]
__s16	luma_offset[32]
__s16	chroma_weight[32][2]
__s16	chroma_offset[32][2]

Picture Reference

type v4l2_h264_reference

struct v4l2_h264_reference

__u8	fields	Specifies how the picture is referenced. See Reference Fields
__u8	index	Index into the v4l2_ctrl_h264_decode_params.dpb array.

Reference Fields

V4L2_H264_TOP_FIELD_REF	0x1	The top field in field pair is used for short-term reference.
V4L2_H264_BOTTOM_FIELD_REF	0x2	The bottom field in field pair is used for short-term reference.
V4L2_H264_FRAME_REF	0x3	The frame (or the top/bottom fields, if it’s a field pair) is used for short-term reference.

V4L2_CID_STATELESS_H264_DECODE_PARAMS (struct)

Specifies the decode parameters (as extracted from the bitstream) for the associated H264 slice data. This includes the necessary parameters for configuring a stateless hardware decoding pipeline for H264. The bitstream parameters are defined according to ITU-T Rec. H.264 Specification (04/2017 Edition). For further documentation, refer to the above specification, unless there is an explicit comment stating otherwise.

type v4l2_ctrl_h264_decode_params

struct v4l2_ctrl_h264_decode_params

struct v4l2_h264_dpb_entry	dpb[16]
__u16	nal_ref_idc	NAL reference ID value coming from the NAL Unit header
__u16	frame_num
__s32	top_field_order_cnt	Picture Order Count for the coded top field
__s32	bottom_field_order_cnt	Picture Order Count for the coded bottom field
__u16	idr_pic_id
__u16	pic_order_cnt_lsb
__s32	delta_pic_order_cnt_bottom
__s32	delta_pic_order_cnt0
__s32	delta_pic_order_cnt1
__u32	dec_ref_pic_marking_bit_size	Size in bits of the dec_ref_pic_marking() syntax element.
__u32	pic_order_cnt_bit_size	Combined size in bits of the picture order count related syntax elements: pic_order_cnt_lsb, delta_pic_order_cnt_bottom, delta_pic_order_cnt0, and delta_pic_order_cnt1.
__u32	slice_group_change_cycle
__u32	reserved	Applications and drivers must set this to zero.
__u32	flags	See Decode Parameters Flags

Decode Parameters Flags

V4L2_H264_DECODE_PARAM_FLAG_IDR_PIC	0x00000001	That picture is an IDR picture
V4L2_H264_DECODE_PARAM_FLAG_FIELD_PIC	0x00000002
V4L2_H264_DECODE_PARAM_FLAG_BOTTOM_FIELD	0x00000004
V4L2_H264_DECODE_PARAM_FLAG_PFRAME	0x00000008
V4L2_H264_DECODE_PARAM_FLAG_BFRAME	0x00000010

type v4l2_h264_dpb_entry

struct v4l2_h264_dpb_entry

__u64	reference_ts	Timestamp of the V4L2 capture buffer to use as reference, used with B-coded and P-coded frames. The timestamp refers to the timestamp field in struct v4l2_buffer. Use the v4l2_timeval_to_ns() function to convert the struct timeval in struct v4l2_buffer to a __u64.
__u32	pic_num	For short term references, this must match the derived value PicNum (8-28) and for long term references it must match the derived value LongTermPicNum (8-29). When decoding frames (as opposed to fields) pic_num is the same as FrameNumWrap.
__u16	frame_num	For short term references, this must match the frame_num value from the slice header syntax (the driver will wrap the value if needed). For long term references, this must be set to the value of long_term_frame_idx described in the dec_ref_pic_marking() syntax.
__u8	fields	Specifies how the DPB entry is referenced. See Reference Fields
__u8	reserved[5]	Applications and drivers must set this to zero.
__s32	top_field_order_cnt
__s32	bottom_field_order_cnt
__u32	flags	See DPB Entry Flags

DPB Entries Flags

V4L2_H264_DPB_ENTRY_FLAG_VALID	0x00000001	The DPB entry is valid (non-empty) and should be considered.
V4L2_H264_DPB_ENTRY_FLAG_ACTIVE	0x00000002	The DPB entry is used for reference.
V4L2_H264_DPB_ENTRY_FLAG_LONG_TERM	0x00000004	The DPB entry is used for long-term reference.
V4L2_H264_DPB_ENTRY_FLAG_FIELD	0x00000008	The DPB entry is a single field or a complementary field pair.

V4L2_CID_STATELESS_H264_DECODE_MODE (enum)

Specifies the decoding mode to use. Currently exposes slice-based and frame-based decoding but new modes might be added later on. This control is used as a modifier for V4L2_PIX_FMT_H264_SLICE pixel format. Applications that support V4L2_PIX_FMT_H264_SLICE are required to set this control in order to specify the decoding mode that is expected for the buffer. Drivers may expose a single or multiple decoding modes, depending on what they can support.

type v4l2_stateless_h264_decode_mode

V4L2_STATELESS_H264_DECODE_MODE_SLICE_BASED	0	Decoding is done at the slice granularity. The OUTPUT buffer must contain a single slice. When this mode is selected, the V4L2_CID_STATELESS_H264_SLICE_PARAMS control shall be set. When multiple slices compose a frame, use of V4L2_BUF_CAP_SUPPORTS_M2M_HOLD_CAPTURE_BUF flag is required.
V4L2_STATELESS_H264_DECODE_MODE_FRAME_BASED	1	Decoding is done at the frame granularity, The OUTPUT buffer must contain all slices needed to decode the frame. The OUTPUT buffer must also contain both fields. This mode will be supported by devices that parse the slice(s) header(s) in hardware. When this mode is selected, the V4L2_CID_STATELESS_H264_SLICE_PARAMS control shall not be set.

V4L2_CID_STATELESS_H264_START_CODE (enum)

Specifies the H264 slice start code expected for each slice. This control is used as a modifier for V4L2_PIX_FMT_H264_SLICE pixel format. Applications that support V4L2_PIX_FMT_H264_SLICE are required to set this control in order to specify the start code that is expected for the buffer. Drivers may expose a single or multiple start codes, depending on what they can support.

type v4l2_stateless_h264_start_code

V4L2_STATELESS_H264_START_CODE_NONE	0	Selecting this value specifies that H264 slices are passed to the driver without any start code. The bitstream data should be according to ITU-T Rec. H.264 Specification (04/2017 Edition) 7.3.1 NAL unit syntax, hence contains emulation prevention bytes when required.
V4L2_STATELESS_H264_START_CODE_ANNEX_B	1	Selecting this value specifies that H264 slices are expected to be prefixed by Annex B start codes. According to ITU-T Rec. H.264 Specification (04/2017 Edition) valid start codes can be 3-bytes 0x000001 or 4-bytes 0x00000001.

V4L2_CID_STATELESS_FWHT_PARAMS (struct)

Specifies the FWHT (Fast Walsh Hadamard Transform) parameters (as extracted from the bitstream) for the associated FWHT data. This includes the necessary parameters for configuring a stateless hardware decoding pipeline for FWHT. This codec is specific to the vicodec test driver.

type v4l2_ctrl_fwht_params

struct v4l2_ctrl_fwht_params

__u64	backward_ref_ts	Timestamp of the V4L2 capture buffer to use as backward reference, used with P-coded frames. The timestamp refers to the timestamp field in struct v4l2_buffer. Use the v4l2_timeval_to_ns() function to convert the struct timeval in struct v4l2_buffer to a __u64.
__u32	version	The version of the codec. Set to V4L2_FWHT_VERSION.
__u32	width	The width of the frame.
__u32	height	The height of the frame.
__u32	flags	The flags of the frame, see FWHT Flags.
__u32	colorspace	The colorspace of the frame, from enum v4l2_colorspace.
__u32	xfer_func	The transfer function, from enum v4l2_xfer_func.
__u32	ycbcr_enc	The Y’CbCr encoding, from enum v4l2_ycbcr_encoding.
__u32	quantization	The quantization range, from enum v4l2_quantization.

1.16.2. FWHT Flags

V4L2_FWHT_FL_IS_INTERLACED	0x00000001	Set if this is an interlaced format.
V4L2_FWHT_FL_IS_BOTTOM_FIRST	0x00000002	Set if this is a bottom-first (NTSC) interlaced format.
V4L2_FWHT_FL_IS_ALTERNATE	0x00000004	Set if each ‘frame’ contains just one field.
V4L2_FWHT_FL_IS_BOTTOM_FIELD	0x00000008	If V4L2_FWHT_FL_IS_ALTERNATE was set, then this is set if this ‘frame’ is the bottom field, else it is the top field.
V4L2_FWHT_FL_LUMA_IS_UNCOMPRESSED	0x00000010	Set if the Y’ (luma) plane is uncompressed.
V4L2_FWHT_FL_CB_IS_UNCOMPRESSED	0x00000020	Set if the Cb plane is uncompressed.
V4L2_FWHT_FL_CR_IS_UNCOMPRESSED	0x00000040	Set if the Cr plane is uncompressed.
V4L2_FWHT_FL_CHROMA_FULL_HEIGHT	0x00000080	Set if the chroma plane has the same height as the luma plane, else the chroma plane is half the height of the luma plane.
V4L2_FWHT_FL_CHROMA_FULL_WIDTH	0x00000100	Set if the chroma plane has the same width as the luma plane, else the chroma plane is half the width of the luma plane.
V4L2_FWHT_FL_ALPHA_IS_UNCOMPRESSED	0x00000200	Set if the alpha plane is uncompressed.
V4L2_FWHT_FL_I_FRAME	0x00000400	Set if this is an I-frame.
V4L2_FWHT_FL_COMPONENTS_NUM_MSK	0x00070000	The number of color components minus one.
V4L2_FWHT_FL_PIXENC_MSK	0x00180000	The mask for the pixel encoding.
V4L2_FWHT_FL_PIXENC_YUV	0x00080000	Set if the pixel encoding is YUV.
V4L2_FWHT_FL_PIXENC_RGB	0x00100000	Set if the pixel encoding is RGB.
V4L2_FWHT_FL_PIXENC_HSV	0x00180000	Set if the pixel encoding is HSV.

V4L2_CID_STATELESS_VP8_FRAME (struct)

Specifies the frame parameters for the associated VP8 parsed frame data. This includes the necessary parameters for configuring a stateless hardware decoding pipeline for VP8. The bitstream parameters are defined according to VP8.

type v4l2_ctrl_vp8_frame

struct v4l2_ctrl_vp8_frame

struct v4l2_vp8_segment	segment	Structure with segment-based adjustments metadata.
struct v4l2_vp8_loop_filter	lf	Structure with loop filter level adjustments metadata.
struct v4l2_vp8_quantization	quant	Structure with VP8 dequantization indices metadata.
struct v4l2_vp8_entropy	entropy	Structure with VP8 entropy coder probabilities metadata.
struct v4l2_vp8_entropy_coder_state	coder_state	Structure with VP8 entropy coder state.
__u16	width	The width of the frame. Must be set for all frames.
__u16	height	The height of the frame. Must be set for all frames.
__u8	horizontal_scale	Horizontal scaling factor.
__u8	vertical_scale	Vertical scaling factor.
__u8	version	Bitstream version.
__u8	prob_skip_false	Indicates the probability that the macroblock is not skipped.
__u8	prob_intra	Indicates the probability that a macroblock is intra-predicted.
__u8	prob_last	Indicates the probability that the last reference frame is used for inter-prediction
__u8	prob_gf	Indicates the probability that the golden reference frame is used for inter-prediction
__u8	num_dct_parts	Number of DCT coefficients partitions. Must be one of: 1, 2, 4, or 8.
__u32	first_part_size	Size of the first partition, i.e. the control partition.
__u32	first_part_header_bits	Size in bits of the first partition header portion.
__u32	dct_part_sizes[8]	DCT coefficients sizes.
__u64	last_frame_ts	Timestamp for the V4L2 capture buffer to use as last reference frame, used with inter-coded frames. The timestamp refers to the timestamp field in struct v4l2_buffer. Use the v4l2_timeval_to_ns() function to convert the struct timeval in struct v4l2_buffer to a __u64.
__u64	golden_frame_ts	Timestamp for the V4L2 capture buffer to use as last reference frame, used with inter-coded frames. The timestamp refers to the timestamp field in struct v4l2_buffer. Use the v4l2_timeval_to_ns() function to convert the struct timeval in struct v4l2_buffer to a __u64.
__u64	alt_frame_ts	Timestamp for the V4L2 capture buffer to use as alternate reference frame, used with inter-coded frames. The timestamp refers to the timestamp field in struct v4l2_buffer. Use the v4l2_timeval_to_ns() function to convert the struct timeval in struct v4l2_buffer to a __u64.
__u64	flags	See Frame Flags

Frame Flags

V4L2_VP8_FRAME_FLAG_KEY_FRAME	0x01	Indicates if the frame is a key frame.
V4L2_VP8_FRAME_FLAG_EXPERIMENTAL	0x02	Experimental bitstream.
V4L2_VP8_FRAME_FLAG_SHOW_FRAME	0x04	Show frame flag, indicates if the frame is for display.
V4L2_VP8_FRAME_FLAG_MB_NO_SKIP_COEFF	0x08	Enable/disable skipping of macroblocks with no non-zero coefficients.
V4L2_VP8_FRAME_FLAG_SIGN_BIAS_GOLDEN	0x10	Sign of motion vectors when the golden frame is referenced.
V4L2_VP8_FRAME_FLAG_SIGN_BIAS_ALT	0x20	Sign of motion vectors when the alt frame is referenced.

type v4l2_vp8_entropy_coder_state

struct v4l2_vp8_entropy_coder_state

__u8	range	coder state value for “Range”
__u8	value	coder state value for “Value”-
__u8	bit_count	number of bits left.
__u8	padding	Applications and drivers must set this to zero.

type v4l2_vp8_segment

struct v4l2_vp8_segment

__s8	quant_update[4]	Signed quantizer value update.
__s8	lf_update[4]	Signed loop filter level value update.
__u8	segment_probs[3]	Segment probabilities.
__u8	padding	Applications and drivers must set this to zero.
__u32	flags	See Segment Flags

Segment Flags

V4L2_VP8_SEGMENT_FLAG_ENABLED	0x01	Enable/disable segment-based adjustments.
V4L2_VP8_SEGMENT_FLAG_UPDATE_MAP	0x02	Indicates if the macroblock segmentation map is updated in this frame.
V4L2_VP8_SEGMENT_FLAG_UPDATE_FEATURE_DATA	0x04	Indicates if the segment feature data is updated in this frame.
V4L2_VP8_SEGMENT_FLAG_DELTA_VALUE_MODE	0x08	If is set, the segment feature data mode is delta-value. If cleared, it’s absolute-value.

type v4l2_vp8_loop_filter

struct v4l2_vp8_loop_filter

__s8	ref_frm_delta[4]	Reference adjustment (signed) delta value.
__s8	mb_mode_delta[4]	Macroblock prediction mode adjustment (signed) delta value.
__u8	sharpness_level	Sharpness level
__u8	level	Filter level
__u16	padding	Applications and drivers must set this to zero.
__u32	flags	See Loop Filter Flags

Loop Filter Flags

V4L2_VP8_LF_ADJ_ENABLE	0x01	Enable/disable macroblock-level loop filter adjustment.
V4L2_VP8_LF_DELTA_UPDATE	0x02	Indicates if the delta values used in an adjustment are updated.
V4L2_VP8_LF_FILTER_TYPE_SIMPLE	0x04	If set, indicates the filter type is simple. If cleared, the filter type is normal.

type v4l2_vp8_quantization

struct v4l2_vp8_quantization

__u8	y_ac_qi	Luma AC coefficient table index.
__s8	y_dc_delta	Luma DC delta value.
__s8	y2_dc_delta	Y2 block DC delta value.
__s8	y2_ac_delta	Y2 block AC delta value.
__s8	uv_dc_delta	Chroma DC delta value.
__s8	uv_ac_delta	Chroma AC delta value.
__u16	padding	Applications and drivers must set this to zero.

type v4l2_vp8_entropy

struct v4l2_vp8_entropy

__u8	coeff_probs[4][8][3][11]	Coefficient update probabilities.
__u8	y_mode_probs[4]	Luma mode update probabilities.
__u8	uv_mode_probs[3]	Chroma mode update probabilities.
__u8	mv_probs[2][19]	MV decoding update probabilities.
__u8	padding[3]	Applications and drivers must set this to zero.

V4L2_CID_STATELESS_MPEG2_SEQUENCE (struct)

Specifies the sequence parameters (as extracted from the bitstream) for the associated MPEG-2 slice data. This includes fields matching the syntax elements from the sequence header and sequence extension parts of the bitstream as specified by ISO 13818-2.

type v4l2_ctrl_mpeg2_sequence

struct v4l2_ctrl_mpeg2_sequence

__u16	horizontal_size	The width of the displayable part of the frame’s luminance component.
__u16	vertical_size	The height of the displayable part of the frame’s luminance component.
__u32	vbv_buffer_size	Used to calculate the required size of the video buffering verifier, defined (in bits) as: 16 * 1024 * vbv_buffer_size.
__u16	profile_and_level_indication	The current profile and level indication as extracted from the bitstream.
__u8	chroma_format	The chrominance sub-sampling format (1: 4:2:0, 2: 4:2:2, 3: 4:4:4).
__u8	flags	See MPEG-2 Sequence Flags.

MPEG-2 Sequence Flags

V4L2_MPEG2_SEQ_FLAG_PROGRESSIVE

0x01

Indication that all the frames for the sequence are progressive instead of interlaced.

V4L2_CID_STATELESS_MPEG2_PICTURE (struct)

Specifies the picture parameters (as extracted from the bitstream) for the associated MPEG-2 slice data. This includes fields matching the syntax elements from the picture header and picture coding extension parts of the bitstream as specified by ISO 13818-2.

type v4l2_ctrl_mpeg2_picture

struct v4l2_ctrl_mpeg2_picture

__u64	backward_ref_ts	Timestamp of the V4L2 capture buffer to use as backward reference, used with B-coded and P-coded frames. The timestamp refers to the timestamp field in struct v4l2_buffer. Use the v4l2_timeval_to_ns() function to convert the struct timeval in struct v4l2_buffer to a __u64.
__u64	forward_ref_ts	Timestamp for the V4L2 capture buffer to use as forward reference, used with B-coded frames. The timestamp refers to the timestamp field in struct v4l2_buffer. Use the v4l2_timeval_to_ns() function to convert the struct timeval in struct v4l2_buffer to a __u64.
__u32	flags	See MPEG-2 Picture Flags.
__u8	f_code[2][2]	Motion vector codes.
__u8	picture_coding_type	Picture coding type for the frame covered by the current slice (V4L2_MPEG2_PIC_CODING_TYPE_I, V4L2_MPEG2_PIC_CODING_TYPE_P or V4L2_MPEG2_PIC_CODING_TYPE_B).
__u8	picture_structure	Picture structure (1: interlaced top field, 2: interlaced bottom field, 3: progressive frame).
__u8	intra_dc_precision	Precision of Discrete Cosine transform (0: 8 bits precision, 1: 9 bits precision, 2: 10 bits precision, 3: 11 bits precision).
__u8	reserved[5]	Applications and drivers must set this to zero.

MPEG-2 Picture Flags

V4L2_MPEG2_PIC_FLAG_TOP_FIELD_FIRST	0x00000001	If set and it’s an interlaced stream, top field is output first.
V4L2_MPEG2_PIC_FLAG_FRAME_PRED_DCT	0x00000002	If set only frame-DCT and frame prediction are used.
V4L2_MPEG2_PIC_FLAG_CONCEALMENT_MV	0x00000004	If set motion vectors are coded for intra macroblocks.
V4L2_MPEG2_PIC_FLAG_Q_SCALE_TYPE	0x00000008	This flag affects the inverse quantization process.
V4L2_MPEG2_PIC_FLAG_INTRA_VLC	0x00000010	This flag affects the decoding of transform coefficient data.
V4L2_MPEG2_PIC_FLAG_ALT_SCAN	0x00000020	This flag affects the decoding of transform coefficient data.
V4L2_MPEG2_PIC_FLAG_REPEAT_FIRST	0x00000040	This flag affects the decoding process of progressive frames.
V4L2_MPEG2_PIC_FLAG_PROGRESSIVE	0x00000080	Indicates whether the current frame is progressive.

V4L2_CID_STATELESS_MPEG2_QUANTISATION (struct)

Specifies quantisation matrices, in zigzag scanning order, for the associated MPEG-2 slice data. This control is initialized by the kernel to the matrices default values. If a bitstream transmits a user-defined quantisation matrices load, applications are expected to use this control. Applications are also expected to set the control loading the default values, if the quantisation matrices need to be reset, for instance on a sequence header. This process is specified by section 6.3.7. “Quant matrix extension” of the specification.

type v4l2_ctrl_mpeg2_quantisation

struct v4l2_ctrl_mpeg2_quantisation

__u8	intra_quantiser_matrix[64]	The quantisation matrix coefficients for intra-coded frames, in zigzag scanning order. It is relevant for both luma and chroma components, although it can be superseded by the chroma-specific matrix for non-4:2:0 YUV formats.
__u8	non_intra_quantiser_matrix[64]	The quantisation matrix coefficients for non-intra-coded frames, in zigzag scanning order. It is relevant for both luma and chroma components, although it can be superseded by the chroma-specific matrix for non-4:2:0 YUV formats.
__u8	chroma_intra_quantiser_matrix[64]	The quantisation matrix coefficients for the chominance component of intra-coded frames, in zigzag scanning order. Only relevant for non-4:2:0 YUV formats.
__u8	chroma_non_intra_quantiser_matrix[64]	The quantisation matrix coefficients for the chrominance component of non-intra-coded frames, in zigzag scanning order. Only relevant for non-4:2:0 YUV formats.

V4L2_CID_STATELESS_VP9_COMPRESSED_HDR (struct)

Stores VP9 probabilities updates as parsed from the current compressed frame header. A value of zero in an array element means no update of the relevant probability. Motion vector-related updates contain a new value or zero. All other updates contain values translated with inv_map_table[] (see 6.3.5 in VP9).

type v4l2_ctrl_vp9_compressed_hdr

struct v4l2_ctrl_vp9_compressed_hdr

__u8	tx_mode	Specifies the TX mode. See TX Mode for more details.
__u8	tx8[2][1]	TX 8x8 probabilities delta.
__u8	tx16[2][2]	TX 16x16 probabilities delta.
__u8	tx32[2][3]	TX 32x32 probabilities delta.
__u8	coef[4][2][2][6][6][3]	Coefficient probabilities delta.
__u8	skip[3]	Skip probabilities delta.
__u8	inter_mode[7][3]	Inter prediction mode probabilities delta.
__u8	interp_filter[4][2]	Interpolation filter probabilities delta.
__u8	is_inter[4]	Is inter-block probabilities delta.
__u8	comp_mode[5]	Compound prediction mode probabilities delta.
__u8	single_ref[5][2]	Single reference probabilities delta.
__u8	comp_ref[5]	Compound reference probabilities delta.
__u8	y_mode[4][9]	Y prediction mode probabilities delta.
__u8	uv_mode[10][9]	UV prediction mode probabilities delta.
__u8	partition[16][3]	Partition probabilities delta.
__u8	mv.joint[3]	Motion vector joint probabilities delta.
__u8	mv.sign[2]	Motion vector sign probabilities delta.
__u8	mv.classes[2][10]	Motion vector class probabilities delta.
__u8	mv.class0_bit[2]	Motion vector class0 bit probabilities delta.
__u8	mv.bits[2][10]	Motion vector bits probabilities delta.
__u8	mv.class0_fr[2][2][3]	Motion vector class0 fractional bit probabilities delta.
__u8	mv.fr[2][3]	Motion vector fractional bit probabilities delta.
__u8	mv.class0_hp[2]	Motion vector class0 high precision fractional bit probabilities delta.
__u8	mv.hp[2]	Motion vector high precision fractional bit probabilities delta.

TX Mode

V4L2_VP9_TX_MODE_ONLY_4X4	0	Transform size is 4x4.
V4L2_VP9_TX_MODE_ALLOW_8X8	1	Transform size can be up to 8x8.
V4L2_VP9_TX_MODE_ALLOW_16X16	2	Transform size can be up to 16x16.
V4L2_VP9_TX_MODE_ALLOW_32X32	3	transform size can be up to 32x32.
V4L2_VP9_TX_MODE_SELECT	4	Bitstream contains the transform size for each block.

See section ‘7.3.1 Tx mode semantics’ of the VP9 specification for more details.

V4L2_CID_STATELESS_VP9_FRAME (struct)

Specifies the frame parameters for the associated VP9 frame decode request. This includes the necessary parameters for configuring a stateless hardware decoding pipeline for VP9. The bitstream parameters are defined according to VP9.

type v4l2_ctrl_vp9_frame

struct v4l2_ctrl_vp9_frame

struct v4l2_vp9_loop_filter	lf	Loop filter parameters. See struct v4l2_vp9_loop_filter for more details.
struct v4l2_vp9_quantization	quant	Quantization parameters. See v4l2_vp9_quantization for more details.
struct v4l2_vp9_segmentation	seg	Segmentation parameters. See v4l2_vp9_segmentation for more details.
__u32	flags	Combination of V4L2_VP9_FRAME_FLAG_* flags. See Frame Flags.
__u16	compressed_header_size	Compressed header size in bytes.
__u16	uncompressed_header_size	Uncompressed header size in bytes.
__u16	frame_width_minus_1	Add 1 to get the frame width expressed in pixels. See section 7.2.3 in VP9.
__u16	frame_height_minus_1	Add 1 to get the frame height expressed in pixels. See section 7.2.3 in VP9.
__u16	render_width_minus_1	Add 1 to get the expected render width expressed in pixels. This is not used during the decoding process but might be used by HW scalers to prepare a frame that’s ready for scanout. See section 7.2.4 in VP9.
__u16	render_height_minus_1	Add 1 to get the expected render height expressed in pixels. This is not used during the decoding process but might be used by HW scalers to prepare a frame that’s ready for scanout. See section 7.2.4 in VP9.
__u64	last_frame_ts	“last” reference buffer timestamp. The timestamp refers to the timestamp field in struct v4l2_buffer. Use the v4l2_timeval_to_ns() function to convert the struct timeval in struct v4l2_buffer to a __u64.
__u64	golden_frame_ts	“golden” reference buffer timestamp. The timestamp refers to the timestamp field in struct v4l2_buffer. Use the v4l2_timeval_to_ns() function to convert the struct timeval in struct v4l2_buffer to a __u64.
__u64	alt_frame_ts	“alt” reference buffer timestamp. The timestamp refers to the timestamp field in struct v4l2_buffer. Use the v4l2_timeval_to_ns() function to convert the struct timeval in struct v4l2_buffer to a __u64.
__u8	ref_frame_sign_bias	a bitfield specifying whether the sign bias is set for a given reference frame. See Reference Frame Sign Bias for more details.
__u8	reset_frame_context	specifies whether the frame context should be reset to default values. See Reset Frame Context for more details.
__u8	frame_context_idx	Frame context that should be used/updated.
__u8	profile	VP9 profile. Can be 0, 1, 2 or 3.
__u8	bit_depth	Component depth in bits. Can be 8, 10 or 12. Note that not all profiles support 10 and/or 12 bits depths.
__u8	interpolation_filter	Specifies the filter selection used for performing inter prediction. See Interpolation Filter for more details.
__u8	tile_cols_log2	Specifies the base 2 logarithm of the width of each tile (where the width is measured in units of 8x8 blocks). Shall be less than or equal to 6.
__u8	tile_rows_log2	Specifies the base 2 logarithm of the height of each tile (where the height is measured in units of 8x8 blocks).
__u8	reference_mode	Specifies the type of inter prediction to be used. See Reference Mode for more details. Note that this is derived as part of the compressed header parsing process and for this reason should have been part of :c:type: v4l2_ctrl_vp9_compressed_hdr optional control. It is safe to set this value to zero if the driver does not require compressed headers.
__u8	reserved[7]	Applications and drivers must set this to zero.

Frame Flags

V4L2_VP9_FRAME_FLAG_KEY_FRAME	0x001	The frame is a key frame.
V4L2_VP9_FRAME_FLAG_SHOW_FRAME	0x002	The frame should be displayed.
V4L2_VP9_FRAME_FLAG_ERROR_RESILIENT	0x004	The decoding should be error resilient.
V4L2_VP9_FRAME_FLAG_INTRA_ONLY	0x008	The frame does not reference other frames.
V4L2_VP9_FRAME_FLAG_ALLOW_HIGH_PREC_MV	0x010	The frame can use high precision motion vectors.
V4L2_VP9_FRAME_FLAG_REFRESH_FRAME_CTX	0x020	Frame context should be updated after decoding.
V4L2_VP9_FRAME_FLAG_PARALLEL_DEC_MODE	0x040	Parallel decoding is used.
V4L2_VP9_FRAME_FLAG_X_SUBSAMPLING	0x080	Vertical subsampling is enabled.
V4L2_VP9_FRAME_FLAG_Y_SUBSAMPLING	0x100	Horizontal subsampling is enabled.
V4L2_VP9_FRAME_FLAG_COLOR_RANGE_FULL_SWING	0x200	The full UV range is used.

Reference Frame Sign Bias

V4L2_VP9_SIGN_BIAS_LAST	0x1	Sign bias is set for the last reference frame.
V4L2_VP9_SIGN_BIAS_GOLDEN	0x2	Sign bias is set for the golden reference frame.
V4L2_VP9_SIGN_BIAS_ALT	0x2	Sign bias is set for the alt reference frame.

Reset Frame Context

V4L2_VP9_RESET_FRAME_CTX_NONE	0	Do not reset any frame context.
V4L2_VP9_RESET_FRAME_CTX_SPEC	1	Reset the frame context pointed to by v4l2_ctrl_vp9_frame.frame_context_idx.
V4L2_VP9_RESET_FRAME_CTX_ALL	2	Reset all frame contexts.

See section ‘7.2 Uncompressed header semantics’ of the VP9 specification for more details.

Interpolation Filter

V4L2_VP9_INTERP_FILTER_EIGHTTAP	0	Eight tap filter.
V4L2_VP9_INTERP_FILTER_EIGHTTAP_SMOOTH	1	Eight tap smooth filter.
V4L2_VP9_INTERP_FILTER_EIGHTTAP_SHARP	2	Eeight tap sharp filter.
V4L2_VP9_INTERP_FILTER_BILINEAR	3	Bilinear filter.
V4L2_VP9_INTERP_FILTER_SWITCHABLE	4	Filter selection is signaled at the block level.

See section ‘7.2.7 Interpolation filter semantics’ of the VP9 specification for more details.

Reference Mode

V4L2_VP9_REFERENCE_MODE_SINGLE_REFERENCE	0	Indicates that all the inter blocks use only a single reference frame to generate motion compensated prediction.
V4L2_VP9_REFERENCE_MODE_COMPOUND_REFERENCE	1	Requires all the inter blocks to use compound mode. Single reference frame prediction is not allowed.
V4L2_VP9_REFERENCE_MODE_SELECT	2	Allows each individual inter block to select between single and compound prediction modes.

See section ‘7.3.6 Frame reference mode semantics’ of the VP9 specification for more details.

type v4l2_vp9_segmentation

Encodes the quantization parameters. See section ‘7.2.10 Segmentation params syntax’ of the VP9 specification for more details.

struct v4l2_vp9_segmentation

__u8	feature_data[8][4]	Data attached to each feature. Data entry is only valid if the feature is enabled. The array shall be indexed with segment number as the first dimension (0..7) and one of V4L2_VP9_SEG_* as the second dimension. See Segment Feature IDs.
__u8	feature_enabled[8]	Bitmask defining which features are enabled in each segment. The value for each segment is a combination of V4L2_VP9_SEGMENT_FEATURE_ENABLED(id) values where id is one of V4L2_VP9_SEG_*. See Segment Feature IDs.
__u8	tree_probs[7]	Specifies the probability values to be used when decoding a Segment-ID. See ‘5.15 Segmentation map’ section of VP9 for more details.
__u8	pred_probs[3]	Specifies the probability values to be used when decoding a Predicted-Segment-ID. See ‘6.4.14 Get segment id syntax’ section of VP9 for more details.
__u8	flags	Combination of V4L2_VP9_SEGMENTATION_FLAG_* flags. See Segmentation Flags.
__u8	reserved[5]	Applications and drivers must set this to zero.

Segment feature IDs

V4L2_VP9_SEG_LVL_ALT_Q	0	Quantizer segment feature.
V4L2_VP9_SEG_LVL_ALT_L	1	Loop filter segment feature.
V4L2_VP9_SEG_LVL_REF_FRAME	2	Reference frame segment feature.
V4L2_VP9_SEG_LVL_SKIP	3	Skip segment feature.
V4L2_VP9_SEG_LVL_MAX	4	Number of segment features.

Segmentation Flags

V4L2_VP9_SEGMENTATION_FLAG_ENABLED	0x01	Indicates that this frame makes use of the segmentation tool.
V4L2_VP9_SEGMENTATION_FLAG_UPDATE_MAP	0x02	Indicates that the segmentation map should be updated during the decoding of this frame.
V4L2_VP9_SEGMENTATION_FLAG_TEMPORAL_UPDATE	0x04	Indicates that the updates to the segmentation map are coded relative to the existing segmentation map.
V4L2_VP9_SEGMENTATION_FLAG_UPDATE_DATA	0x08	Indicates that new parameters are about to be specified for each segment.
V4L2_VP9_SEGMENTATION_FLAG_ABS_OR_DELTA_UPDATE	0x10	Indicates that the segmentation parameters represent the actual values to be used.

type v4l2_vp9_quantization

Encodes the quantization parameters. See section ‘7.2.9 Quantization params syntax’ of the VP9 specification for more details.

struct v4l2_vp9_quantization

__u8	base_q_idx	Indicates the base frame qindex.
__s8	delta_q_y_dc	Indicates the Y DC quantizer relative to base_q_idx.
__s8	delta_q_uv_dc	Indicates the UV DC quantizer relative to base_q_idx.
__s8	delta_q_uv_ac	Indicates the UV AC quantizer relative to base_q_idx.
__u8	reserved[4]	Applications and drivers must set this to zero.

type v4l2_vp9_loop_filter

This structure contains all loop filter related parameters. See sections ‘7.2.8 Loop filter semantics’ of the VP9 specification for more details.

struct v4l2_vp9_loop_filter

__s8	ref_deltas[4]	Contains the adjustment needed for the filter level based on the chosen reference frame.
__s8	mode_deltas[2]	Contains the adjustment needed for the filter level based on the chosen mode.
__u8	level	Indicates the loop filter strength.
__u8	sharpness	Indicates the sharpness level.
__u8	flags	Combination of V4L2_VP9_LOOP_FILTER_FLAG_* flags. See Loop Filter Flags.
__u8	reserved[7]	Applications and drivers must set this to zero.

Loop Filter Flags

V4L2_VP9_LOOP_FILTER_FLAG_DELTA_ENABLED	0x1	When set, the filter level depends on the mode and reference frame used to predict a block.
V4L2_VP9_LOOP_FILTER_FLAG_DELTA_UPDATE	0x2	When set, the bitstream contains additional syntax elements that specify which mode and reference frame deltas are to be updated.

V4L2_CID_STATELESS_HEVC_SPS (struct)

Specifies the Sequence Parameter Set fields (as extracted from the bitstream) for the associated HEVC slice data. These bitstream parameters are defined according to ITU H.265/HEVC. They are described in section 7.4.3.2 “Sequence parameter set RBSP semantics” of the specification.

type v4l2_ctrl_hevc_sps

struct v4l2_ctrl_hevc_sps

__u8	video_parameter_set_id	Specifies the value of the vps_video_parameter_set_id of the active VPS as described in section “7.4.3.2.1 General sequence parameter set RBSP semantics” of H.265 specifications.
__u8	seq_parameter_set_id	Provides an identifier for the SPS for reference by other syntax elements as described in section “7.4.3.2.1 General sequence parameter set RBSP semantics” of H.265 specifications.
__u16	pic_width_in_luma_samples	Specifies the width of each decoded picture in units of luma samples.
__u16	pic_height_in_luma_samples	Specifies the height of each decoded picture in units of luma samples.
__u8	bit_depth_luma_minus8	This value plus 8 specifies the bit depth of the samples of the luma array.
__u8	bit_depth_chroma_minus8	This value plus 8 specifies the bit depth of the samples of the chroma arrays.
__u8	log2_max_pic_order_cnt_lsb_minus4	Specifies the value of the variable MaxPicOrderCntLsb.
__u8	sps_max_dec_pic_buffering_minus1	This value plus 1 specifies the maximum required size of the decoded picture buffer for the coded video sequence (CVS).
__u8	sps_max_num_reorder_pics	Indicates the maximum allowed number of pictures.
__u8	sps_max_latency_increase_plus1	Used to signal MaxLatencyPictures, which indicates the maximum number of pictures that can precede any picture in output order and follow that picture in decoding order.
__u8	log2_min_luma_coding_block_size_minus3	This value plus 3 specifies the minimum luma coding block size.
__u8	log2_diff_max_min_luma_coding_block_size	Specifies the difference between the maximum and minimum luma coding block size.
__u8	log2_min_luma_transform_block_size_minus2	This value plus 2 specifies the minimum luma transform block size.
__u8	log2_diff_max_min_luma_transform_block_size	Specifies the difference between the maximum and minimum luma transform block size.
__u8	max_transform_hierarchy_depth_inter	Specifies the maximum hierarchy depth for transform units of coding units coded in inter prediction mode.
__u8	max_transform_hierarchy_depth_intra	Specifies the maximum hierarchy depth for transform units of coding units coded in intra prediction mode.
__u8	pcm_sample_bit_depth_luma_minus1	This value plus 1 specifies the number of bits used to represent each of PCM sample values of the luma component.
__u8	pcm_sample_bit_depth_chroma_minus1	Specifies the number of bits used to represent each of PCM sample values of the chroma components.
__u8	log2_min_pcm_luma_coding_block_size_minus3	Plus 3 specifies the minimum size of coding blocks.
__u8	log2_diff_max_min_pcm_luma_coding_block_size	Specifies the difference between the maximum and minimum size of coding blocks.
__u8	num_short_term_ref_pic_sets	Specifies the number of st_ref_pic_set() syntax structures included in the SPS.
__u8	num_long_term_ref_pics_sps	Specifies the number of candidate long-term reference pictures that are specified in the SPS.
__u8	chroma_format_idc	Specifies the chroma sampling.
__u8	sps_max_sub_layers_minus1	This value plus 1 specifies the maximum number of temporal sub-layers.
__u64	flags	See Sequence Parameter Set Flags

Sequence Parameter Set Flags

V4L2_HEVC_SPS_FLAG_SEPARATE_COLOUR_PLANE	0x00000001
V4L2_HEVC_SPS_FLAG_SCALING_LIST_ENABLED	0x00000002
V4L2_HEVC_SPS_FLAG_AMP_ENABLED	0x00000004
V4L2_HEVC_SPS_FLAG_SAMPLE_ADAPTIVE_OFFSET	0x00000008
V4L2_HEVC_SPS_FLAG_PCM_ENABLED	0x00000010
V4L2_HEVC_SPS_FLAG_PCM_LOOP_FILTER_DISABLED	0x00000020
V4L2_HEVC_SPS_FLAG_LONG_TERM_REF_PICS_PRESENT	0x00000040
V4L2_HEVC_SPS_FLAG_SPS_TEMPORAL_MVP_ENABLED	0x00000080
V4L2_HEVC_SPS_FLAG_STRONG_INTRA_SMOOTHING_ENABLED	0x00000100

V4L2_CID_STATELESS_HEVC_PPS (struct)

Specifies the Picture Parameter Set fields (as extracted from the bitstream) for the associated HEVC slice data. These bitstream parameters are defined according to ITU H.265/HEVC. They are described in section 7.4.3.3 “Picture parameter set RBSP semantics” of the specification.

type v4l2_ctrl_hevc_pps

struct v4l2_ctrl_hevc_pps

__u8	pic_parameter_set_id	Identifies the PPS for reference by other syntax elements.
__u8	num_extra_slice_header_bits	Specifies the number of extra slice header bits that are present in the slice header RBSP for coded pictures referring to the PPS.
__u8	num_ref_idx_l0_default_active_minus1	This value plus 1 specifies the inferred value of num_ref_idx_l0_active_minus1.
__u8	num_ref_idx_l1_default_active_minus1	This value plus 1 specifies the inferred value of num_ref_idx_l1_active_minus1.
__s8	init_qp_minus26	This value plus 26 specifies the initial value of SliceQp Y for each slice referring to the PPS.
__u8	diff_cu_qp_delta_depth	Specifies the difference between the luma coding tree block size and the minimum luma coding block size of coding units that convey cu_qp_delta_abs and cu_qp_delta_sign_flag.
__s8	pps_cb_qp_offset	Specifies the offsets to the luma quantization parameter Cb.
__s8	pps_cr_qp_offset	Specifies the offsets to the luma quantization parameter Cr.
__u8	num_tile_columns_minus1	This value plus 1 specifies the number of tile columns partitioning the picture.
__u8	num_tile_rows_minus1	This value plus 1 specifies the number of tile rows partitioning the picture.
__u8	column_width_minus1[20]	This value plus 1 specifies the width of the i-th tile column in units of coding tree blocks.
__u8	row_height_minus1[22]	This value plus 1 specifies the height of the i-th tile row in units of coding tree blocks.
__s8	pps_beta_offset_div2	Specifies the default deblocking parameter offsets for beta divided by 2.
__s8	pps_tc_offset_div2	Specifies the default deblocking parameter offsets for tC divided by 2.
__u8	log2_parallel_merge_level_minus2	This value plus 2 specifies the value of the variable Log2ParMrgLevel.
__u8	padding[4]	Applications and drivers must set this to zero.
__u64	flags	See Picture Parameter Set Flags

Picture Parameter Set Flags

V4L2_HEVC_PPS_FLAG_DEPENDENT_SLICE_SEGMENT_ENABLED	0x00000001
V4L2_HEVC_PPS_FLAG_OUTPUT_FLAG_PRESENT	0x00000002
V4L2_HEVC_PPS_FLAG_SIGN_DATA_HIDING_ENABLED	0x00000004
V4L2_HEVC_PPS_FLAG_CABAC_INIT_PRESENT	0x00000008
V4L2_HEVC_PPS_FLAG_CONSTRAINED_INTRA_PRED	0x00000010
V4L2_HEVC_PPS_FLAG_TRANSFORM_SKIP_ENABLED	0x00000020
V4L2_HEVC_PPS_FLAG_CU_QP_DELTA_ENABLED	0x00000040
V4L2_HEVC_PPS_FLAG_PPS_SLICE_CHROMA_QP_OFFSETS_PRESENT	0x00000080
V4L2_HEVC_PPS_FLAG_WEIGHTED_PRED	0x00000100
V4L2_HEVC_PPS_FLAG_WEIGHTED_BIPRED	0x00000200
V4L2_HEVC_PPS_FLAG_TRANSQUANT_BYPASS_ENABLED	0x00000400
V4L2_HEVC_PPS_FLAG_TILES_ENABLED	0x00000800
V4L2_HEVC_PPS_FLAG_ENTROPY_CODING_SYNC_ENABLED	0x00001000
V4L2_HEVC_PPS_FLAG_LOOP_FILTER_ACROSS_TILES_ENABLED	0x00002000
V4L2_HEVC_PPS_FLAG_PPS_LOOP_FILTER_ACROSS_SLICES_ENABLED	0x00004000
V4L2_HEVC_PPS_FLAG_DEBLOCKING_FILTER_OVERRIDE_ENABLED	0x00008000
V4L2_HEVC_PPS_FLAG_PPS_DISABLE_DEBLOCKING_FILTER	0x00010000
V4L2_HEVC_PPS_FLAG_LISTS_MODIFICATION_PRESENT	0x00020000
V4L2_HEVC_PPS_FLAG_SLICE_SEGMENT_HEADER_EXTENSION_PRESENT	0x00040000
V4L2_HEVC_PPS_FLAG_DEBLOCKING_FILTER_CONTROL_PRESENT	0x00080000	Specifies the presence of deblocking filter control syntax elements in the PPS
V4L2_HEVC_PPS_FLAG_UNIFORM_SPACING	0x00100000	Specifies that tile column boundaries and likewise tile row boundaries are distributed uniformly across the picture

V4L2_CID_STATELESS_HEVC_SLICE_PARAMS (struct)

Specifies various slice-specific parameters, especially from the NAL unit header, general slice segment header and weighted prediction parameter parts of the bitstream. These bitstream parameters are defined according to ITU H.265/HEVC. They are described in section 7.4.7 “General slice segment header semantics” of the specification. This control is a dynamically sized 1-dimensional array, V4L2_CTRL_FLAG_DYNAMIC_ARRAY flag must be set when using it.

type v4l2_ctrl_hevc_slice_params

struct v4l2_ctrl_hevc_slice_params

__u32	bit_size	Size (in bits) of the current slice data.
__u32	data_byte_offset	Offset (in byte) to the video data in the current slice data.
__u32	num_entry_point_offsets	Specifies the number of entry point offset syntax elements in the slice header. When the driver supports it, the V4L2_CID_STATELESS_HEVC_ENTRY_POINT_OFFSETS must be set.
__u8	nal_unit_type	Specifies the coding type of the slice (B, P or I).
__u8	nuh_temporal_id_plus1	Minus 1 specifies a temporal identifier for the NAL unit.
__u8	slice_type	(V4L2_HEVC_SLICE_TYPE_I, V4L2_HEVC_SLICE_TYPE_P or V4L2_HEVC_SLICE_TYPE_B).
__u8	colour_plane_id	Specifies the colour plane associated with the current slice.
__s32	slice_pic_order_cnt	Specifies the picture order count.
__u8	num_ref_idx_l0_active_minus1	This value plus 1 specifies the maximum reference index for reference picture list 0 that may be used to decode the slice.
__u8	num_ref_idx_l1_active_minus1	This value plus 1 specifies the maximum reference index for reference picture list 1 that may be used to decode the slice.
__u8	collocated_ref_idx	Specifies the reference index of the collocated picture used for temporal motion vector prediction.
__u8	five_minus_max_num_merge_cand	Specifies the maximum number of merging motion vector prediction candidates supported in the slice subtracted from 5.
__s8	slice_qp_delta	Specifies the initial value of QpY to be used for the coding blocks in the slice.
__s8	slice_cb_qp_offset	Specifies a difference to be added to the value of pps_cb_qp_offset.
__s8	slice_cr_qp_offset	Specifies a difference to be added to the value of pps_cr_qp_offset.
__s8	slice_act_y_qp_offset	Specifies the offset to the luma of quantization parameter qP derived in section 8.6.2
__s8	slice_act_cb_qp_offset	Specifies the offset to the cb of quantization parameter qP derived in section 8.6.2
__s8	slice_act_cr_qp_offset	Specifies the offset to the cr of quantization parameter qP derived in section 8.6.2
__s8	slice_beta_offset_div2	Specifies the deblocking parameter offsets for beta divided by 2.
__s8	slice_tc_offset_div2	Specifies the deblocking parameter offsets for tC divided by 2.
__u8	pic_struct	Indicates whether a picture should be displayed as a frame or as one or more fields.
__u32	slice_segment_addr	Specifies the address of the first coding tree block in the slice segment.
__u8	ref_idx_l0[V4L2_HEVC_DPB_ENTRIES_NUM_MAX]	The list of L0 reference elements as indices in the DPB.
__u8	ref_idx_l1[V4L2_HEVC_DPB_ENTRIES_NUM_MAX]	The list of L1 reference elements as indices in the DPB.
__u16	short_term_ref_pic_set_size	Specifies the size, in bits, of the short-term reference picture set, described as st_ref_pic_set() in the specification, included in the slice header or SPS (section 7.3.6.1).
__u16	long_term_ref_pic_set_size	Specifies the size, in bits, of the long-term reference picture set include in the slice header or SPS. It is the number of bits in the conditional block if(long_term_ref_pics_present_flag) in section 7.3.6.1 of the specification.
__u8	padding	Applications and drivers must set this to zero.
struct v4l2_hevc_pred_weight_table	pred_weight_table	The prediction weight coefficients for inter-picture prediction.
__u64	flags	See Slice Parameters Flags

Slice Parameters Flags

V4L2_HEVC_SLICE_PARAMS_FLAG_SLICE_SAO_LUMA	0x00000001
V4L2_HEVC_SLICE_PARAMS_FLAG_SLICE_SAO_CHROMA	0x00000002
V4L2_HEVC_SLICE_PARAMS_FLAG_SLICE_TEMPORAL_MVP_ENABLED	0x00000004
V4L2_HEVC_SLICE_PARAMS_FLAG_MVD_L1_ZERO	0x00000008
V4L2_HEVC_SLICE_PARAMS_FLAG_CABAC_INIT	0x00000010
V4L2_HEVC_SLICE_PARAMS_FLAG_COLLOCATED_FROM_L0	0x00000020
V4L2_HEVC_SLICE_PARAMS_FLAG_USE_INTEGER_MV	0x00000040
V4L2_HEVC_SLICE_PARAMS_FLAG_SLICE_DEBLOCKING_FILTER_DISABLED	0x00000080
V4L2_HEVC_SLICE_PARAMS_FLAG_SLICE_LOOP_FILTER_ACROSS_SLICES_ENABLED	0x00000100
V4L2_HEVC_SLICE_PARAMS_FLAG_DEPENDENT_SLICE_SEGMENT	0x00000200

V4L2_CID_STATELESS_HEVC_ENTRY_POINT_OFFSETS (integer)

Specifies entry point offsets in bytes. This control is a dynamically sized array. The number of entry point offsets is reported by the elems field. This bitstream parameter is defined according to ITU H.265/HEVC. They are described in section 7.4.7.1 “General slice segment header semantics” of the specification. When multiple slices are submitted in a request, the length of this array must be the sum of num_entry_point_offsets of all the slices in the request.

V4L2_CID_STATELESS_HEVC_SCALING_MATRIX (struct)

Specifies the HEVC scaling matrix parameters used for the scaling process for transform coefficients. These matrix and parameters are defined according to ITU H.265/HEVC. They are described in section 7.4.5 “Scaling list data semantics” of the specification.

type v4l2_ctrl_hevc_scaling_matrix

struct v4l2_ctrl_hevc_scaling_matrix

__u8	scaling_list_4x4[6][16]	Scaling list is used for the scaling process for transform coefficients. The values on each scaling list are expected in raster scan order.
__u8	scaling_list_8x8[6][64]	Scaling list is used for the scaling process for transform coefficients. The values on each scaling list are expected in raster scan order.
__u8	scaling_list_16x16[6][64]	Scaling list is used for the scaling process for transform coefficients. The values on each scaling list are expected in raster scan order.
__u8	scaling_list_32x32[2][64]	Scaling list is used for the scaling process for transform coefficients. The values on each scaling list are expected in raster scan order.
__u8	scaling_list_dc_coef_16x16[6]	Scaling list is used for the scaling process for transform coefficients. The values on each scaling list are expected in raster scan order.
__u8	scaling_list_dc_coef_32x32[2]	Scaling list is used for the scaling process for transform coefficients. The values on each scaling list are expected in raster scan order.

type v4l2_hevc_dpb_entry

struct v4l2_hevc_dpb_entry

__u64	timestamp	Timestamp of the V4L2 capture buffer to use as reference, used with B-coded and P-coded frames. The timestamp refers to the timestamp field in struct v4l2_buffer. Use the v4l2_timeval_to_ns() function to convert the struct timeval in struct v4l2_buffer to a __u64.
__u8	flags	Long term flag for the reference frame (V4L2_HEVC_DPB_ENTRY_LONG_TERM_REFERENCE). The flag is set as described in the ITU HEVC specification chapter “8.3.2 Decoding process for reference picture set”.
__u8	field_pic	Whether the reference is a field picture or a frame. See HEVC dpb field pic Flags
__s32	pic_order_cnt_val	The picture order count of the current picture.
__u8	padding[2]	Applications and drivers must set this to zero.

HEVC dpb field pic Flags

V4L2_HEVC_SEI_PIC_STRUCT_FRAME	0	(progressive) Frame
V4L2_HEVC_SEI_PIC_STRUCT_TOP_FIELD	1	Top field
V4L2_HEVC_SEI_PIC_STRUCT_BOTTOM_FIELD	2	Bottom field
V4L2_HEVC_SEI_PIC_STRUCT_TOP_BOTTOM	3	Top field, bottom field, in that order
V4L2_HEVC_SEI_PIC_STRUCT_BOTTOM_TOP	4	Bottom field, top field, in that order
V4L2_HEVC_SEI_PIC_STRUCT_TOP_BOTTOM_TOP	5	Top field, bottom field, top field repeated, in that order
V4L2_HEVC_SEI_PIC_STRUCT_BOTTOM_TOP_BOTTOM	6	Bottom field, top field, bottom field repeated, in that order
V4L2_HEVC_SEI_PIC_STRUCT_FRAME_DOUBLING	7	Frame doubling
V4L2_HEVC_SEI_PIC_STRUCT_FRAME_TRIPLING	8	Frame tripling
V4L2_HEVC_SEI_PIC_STRUCT_TOP_PAIRED_PREVIOUS_BOTTOM	9	Top field paired with previous bottom field in output order
V4L2_HEVC_SEI_PIC_STRUCT_BOTTOM_PAIRED_PREVIOUS_TOP	10	Bottom field paired with previous top field in output order
V4L2_HEVC_SEI_PIC_STRUCT_TOP_PAIRED_NEXT_BOTTOM	11	Top field paired with next bottom field in output order
V4L2_HEVC_SEI_PIC_STRUCT_BOTTOM_PAIRED_NEXT_TOP	12	Bottom field paired with next top field in output order

type v4l2_hevc_pred_weight_table

struct v4l2_hevc_pred_weight_table

__s8	delta_luma_weight_l0[V4L2_HEVC_DPB_ENTRIES_NUM_MAX]	The difference of the weighting factor applied to the luma prediction value for list 0.
__s8	luma_offset_l0[V4L2_HEVC_DPB_ENTRIES_NUM_MAX]	The additive offset applied to the luma prediction value for list 0.
__s8	delta_chroma_weight_l0[V4L2_HEVC_DPB_ENTRIES_NUM_MAX][2]	The difference of the weighting factor applied to the chroma prediction value for list 0.
__s8	chroma_offset_l0[V4L2_HEVC_DPB_ENTRIES_NUM_MAX][2]	The difference of the additive offset applied to the chroma prediction values for list 0.
__s8	delta_luma_weight_l1[V4L2_HEVC_DPB_ENTRIES_NUM_MAX]	The difference of the weighting factor applied to the luma prediction value for list 1.
__s8	luma_offset_l1[V4L2_HEVC_DPB_ENTRIES_NUM_MAX]	The additive offset applied to the luma prediction value for list 1.
__s8	delta_chroma_weight_l1[V4L2_HEVC_DPB_ENTRIES_NUM_MAX][2]	The difference of the weighting factor applied to the chroma prediction value for list 1.
__s8	chroma_offset_l1[V4L2_HEVC_DPB_ENTRIES_NUM_MAX][2]	The difference of the additive offset applied to the chroma prediction values for list 1.
__u8	luma_log2_weight_denom	The base 2 logarithm of the denominator for all luma weighting factors.
__s8	delta_chroma_log2_weight_denom	The difference of the base 2 logarithm of the denominator for all chroma weighting factors.
__u8	padding[6]	Applications and drivers must set this to zero.

V4L2_CID_STATELESS_HEVC_DECODE_MODE (enum)

Specifies the decoding mode to use. Currently exposes slice-based and frame-based decoding but new modes might be added later on. This control is used as a modifier for V4L2_PIX_FMT_HEVC_SLICE pixel format. Applications that support V4L2_PIX_FMT_HEVC_SLICE are required to set this control in order to specify the decoding mode that is expected for the buffer. Drivers may expose a single or multiple decoding modes, depending on what they can support.

type v4l2_stateless_hevc_decode_mode

V4L2_STATELESS_HEVC_DECODE_MODE_SLICE_BASED	0	Decoding is done at the slice granularity. The OUTPUT buffer must contain a single slice.
V4L2_STATELESS_HEVC_DECODE_MODE_FRAME_BASED	1	Decoding is done at the frame granularity. The OUTPUT buffer must contain all slices needed to decode the frame.

V4L2_CID_STATELESS_HEVC_START_CODE (enum)

Specifies the HEVC slice start code expected for each slice. This control is used as a modifier for V4L2_PIX_FMT_HEVC_SLICE pixel format. Applications that support V4L2_PIX_FMT_HEVC_SLICE are required to set this control in order to specify the start code that is expected for the buffer. Drivers may expose a single or multiple start codes, depending on what they can support.

type v4l2_stateless_hevc_start_code

V4L2_STATELESS_HEVC_START_CODE_NONE	0	Selecting this value specifies that HEVC slices are passed to the driver without any start code. The bitstream data should be according to ITU H.265/HEVC 7.3.1.1 General NAL unit syntax, hence contains emulation prevention bytes when required.
V4L2_STATELESS_HEVC_START_CODE_ANNEX_B	1	Selecting this value specifies that HEVC slices are expected to be prefixed by Annex B start codes. According to ITU H.265/HEVC valid start codes can be 3-bytes 0x000001 or 4-bytes 0x00000001.

V4L2_CID_MPEG_VIDEO_BASELAYER_PRIORITY_ID (integer)

Specifies a priority identifier for the NAL unit, which will be applied to the base layer. By default this value is set to 0 for the base layer, and the next layer will have the priority ID assigned as 1, 2, 3 and so on. The video encoder can’t decide the priority id to be applied to a layer, so this has to come from client. This is applicable to H264 and valid Range is from 0 to 63. Source Rec. ITU-T H.264 (06/2019); G.7.4.1.1, G.8.8.1.

V4L2_CID_MPEG_VIDEO_LTR_COUNT (integer)

Specifies the maximum number of Long Term Reference (LTR) frames at any given time that the encoder can keep. This is applicable to the H264 and HEVC encoders.

V4L2_CID_MPEG_VIDEO_FRAME_LTR_INDEX (integer)

After setting this control the frame that will be queued next will be marked as a Long Term Reference (LTR) frame and given this LTR index which ranges from 0 to LTR_COUNT-1. This is applicable to the H264 and HEVC encoders. Source Rec. ITU-T H.264 (06/2019); Table 7.9

V4L2_CID_MPEG_VIDEO_USE_LTR_FRAMES (bitmask)

Specifies the Long Term Reference (LTR) frame(s) to be used for encoding the next frame queued after setting this control. This provides a bitmask which consists of bits [0, LTR_COUNT-1]. This is applicable to the H264 and HEVC encoders.

V4L2_CID_STATELESS_HEVC_DECODE_PARAMS (struct)

Specifies various decode parameters, especially the references picture order count (POC) for all the lists (short, long, before, current, after) and the number of entries for each of them. These parameters are defined according to ITU H.265/HEVC. They are described in section 8.3 “Slice decoding process” of the specification.

type v4l2_ctrl_hevc_decode_params

struct v4l2_ctrl_hevc_decode_params

__s32	pic_order_cnt_val	PicOrderCntVal as described in section 8.3.1 “Decoding process for picture order count” of the specification.
__u16	short_term_ref_pic_set_size	Specifies the size, in bits, of the short-term reference picture set, of the first slice described as st_ref_pic_set() in the specification, included in the slice header or SPS (section 7.3.6.1).
__u16	long_term_ref_pic_set_size	Specifies the size, in bits, of the long-term reference picture set, of the first slice included in the slice header or SPS. It is the number of bits in the conditional block if(long_term_ref_pics_present_flag) in section 7.3.6.1 of the specification.
__u8	num_active_dpb_entries	The number of entries in dpb.
__u8	num_poc_st_curr_before	The number of reference pictures in the short-term set that come before the current frame.
__u8	num_poc_st_curr_after	The number of reference pictures in the short-term set that come after the current frame.
__u8	num_poc_lt_curr	The number of reference pictures in the long-term set.
__u8	poc_st_curr_before[V4L2_HEVC_DPB_ENTRIES_NUM_MAX]	PocStCurrBefore as described in section 8.3.2 “Decoding process for reference picture set”: provides the index of the short term before references in DPB array.
__u8	poc_st_curr_after[V4L2_HEVC_DPB_ENTRIES_NUM_MAX]	PocStCurrAfter as described in section 8.3.2 “Decoding process for reference picture set”: provides the index of the short term after references in DPB array.
__u8	poc_lt_curr[V4L2_HEVC_DPB_ENTRIES_NUM_MAX]	PocLtCurr as described in section 8.3.2 “Decoding process for reference picture set”: provides the index of the long term references in DPB array.
__u8	num_delta_pocs_of_ref_rps_idx	When the short_term_ref_pic_set_sps_flag in the slice header is equal to 0, it is the same as the derived value NumDeltaPocs[RefRpsIdx]. It can be used to parse the RPS data in slice headers instead of skipping it with @short_term_ref_pic_set_size. When the value of short_term_ref_pic_set_sps_flag in the slice header is equal to 1, num_delta_pocs_of_ref_rps_idx shall be set to 0.
struct v4l2_hevc_dpb_entry	dpb[V4L2_HEVC_DPB_ENTRIES_NUM_MAX]	The decoded picture buffer, for meta-data about reference frames.
__u64	flags	See Decode Parameters Flags

Decode Parameters Flags

V4L2_HEVC_DECODE_PARAM_FLAG_IRAP_PIC	0x00000001
V4L2_HEVC_DECODE_PARAM_FLAG_IDR_PIC	0x00000002
V4L2_HEVC_DECODE_PARAM_FLAG_NO_OUTPUT_OF_PRIOR	0x00000004

V4L2_CID_STATELESS_AV1_SEQUENCE (struct)

Represents an AV1 Sequence OBU (Open Bitstream Unit). See section 5.5 “Sequence header OBU syntax” in AV1 for more details.

type v4l2_ctrl_av1_sequence

struct v4l2_ctrl_av1_sequence

__u32	flags	See AV1 Sequence Flags.
__u8	seq_profile	Specifies the features that can be used in the coded video sequence.
__u8	order_hint_bits	Specifies the number of bits used for the order_hint field at each frame.
__u8	bit_depth	the bit depth to use for the sequence as described in section 5.5.2 “Color config syntax” in AV1 for more details.
__u8	reserved	Applications and drivers must set this to zero.
__u16	max_frame_width_minus_1	Specifies the maximum frame width minus 1 for the frames represented by this sequence header.
__u16	max_frame_height_minus_1	Specifies the maximum frame height minus 1 for the frames represented by this sequence header.

AV1 Sequence Flags

V4L2_AV1_SEQUENCE_FLAG_STILL_PICTURE	0x00000001	If set, specifies that the coded video sequence contains only one coded frame. If not set, specifies that the coded video sequence contains one or more coded frames.
V4L2_AV1_SEQUENCE_FLAG_USE_128X128_SUPERBLOCK	0x00000002	If set, indicates that superblocks contain 128x128 luma samples. When equal to 0, it indicates that superblocks contain 64x64 luma samples. The number of contained chroma samples depends on subsampling_x and subsampling_y.
V4L2_AV1_SEQUENCE_FLAG_ENABLE_FILTER_INTRA	0x00000004	If set, specifies that the use_filter_intra syntax element may be present. If not set, specifies that the use_filter_intra syntax element will not be present.
V4L2_AV1_SEQUENCE_FLAG_ENABLE_INTRA_EDGE_FILTER	0x00000008	Specifies whether the intra edge filtering process should be enabled.
V4L2_AV1_SEQUENCE_FLAG_ENABLE_INTERINTRA_COMPOUND	0x00000010	If set, specifies that the mode info for inter blocks may contain the syntax element interintra. If not set, specifies that the syntax element interintra will not be present.
V4L2_AV1_SEQUENCE_FLAG_ENABLE_MASKED_COMPOUND	0x00000020	If set, specifies that the mode info for inter blocks may contain the syntax element compound_type. If not set, specifies that the syntax element compound_type will not be present.
V4L2_AV1_SEQUENCE_FLAG_ENABLE_WARPED_MOTION	0x00000040	If set, indicates that the allow_warped_motion syntax element may be present. If not set, indicates that the allow_warped_motion syntax element will not be present.
V4L2_AV1_SEQUENCE_FLAG_ENABLE_DUAL_FILTER	0x00000080	If set, indicates that the inter prediction filter type may be specified independently in the horizontal and vertical directions. If the flag is equal to 0, only one filter type may be specified, which is then used in both directions.
V4L2_AV1_SEQUENCE_FLAG_ENABLE_ORDER_HINT	0x00000100	If set, indicates that tools based on the values of order hints may be used. If not set, indicates that tools based on order hints are disabled.
V4L2_AV1_SEQUENCE_FLAG_ENABLE_JNT_COMP	0x00000200	If set, indicates that the distance weights process may be used for inter prediction.
V4L2_AV1_SEQUENCE_FLAG_ENABLE_REF_FRAME_MVS	0x00000400	If set, indicates that the use_ref_frame_mvs syntax element may be present. If not set, indicates that the use_ref_frame_mvs syntax element will not be present.
V4L2_AV1_SEQUENCE_FLAG_ENABLE_SUPERRES	0x00000800	If set, specifies that the use_superres syntax element will be present in the uncompressed header. If not set, specifies that the use_superres syntax element will not be present (instead use_superres will be set to 0 in the uncompressed header without being read).
V4L2_AV1_SEQUENCE_FLAG_ENABLE_CDEF	0x00001000	If set, specifies that cdef filtering may be enabled. If not set, specifies that cdef filtering is disabled.
V4L2_AV1_SEQUENCE_FLAG_ENABLE_RESTORATION	0x00002000	If set, specifies that loop restoration filtering may be enabled. If not set, specifies that loop restoration filtering is disabled.
V4L2_AV1_SEQUENCE_FLAG_MONO_CHROME	0x00004000	If set, indicates that the video does not contain U and V color planes. If not set, indicates that the video contains Y, U, and V color planes.
V4L2_AV1_SEQUENCE_FLAG_COLOR_RANGE	0x00008000	If set, signals full swing representation, i.e. “Full Range Quantization”. If not set, signals studio swing representation, i.e. “Limited Range Quantization”.
V4L2_AV1_SEQUENCE_FLAG_SUBSAMPLING_X	0x00010000	Specify the chroma subsampling format.
V4L2_AV1_SEQUENCE_FLAG_SUBSAMPLING_Y	0x00020000	Specify the chroma subsampling format.
V4L2_AV1_SEQUENCE_FLAG_FILM_GRAIN_PARAMS_PRESENT	0x00040000	Specifies whether film grain parameters are present in the coded video sequence.
V4L2_AV1_SEQUENCE_FLAG_SEPARATE_UV_DELTA_Q	0x00080000	If set, indicates that the U and V planes may have separate delta quantizer values. If not set, indicates that the U and V planes will share the same delta quantizer value.

V4L2_CID_STATELESS_AV1_TILE_GROUP_ENTRY (struct)

Represents a single AV1 tile inside an AV1 Tile Group. Note that MiRowStart, MiRowEnd, MiColStart and MiColEnd can be retrieved from struct v4l2_av1_tile_info in struct v4l2_ctrl_av1_frame using tile_row and tile_col. See section 6.10.1 “General tile group OBU semantics” in AV1 for more details.

type v4l2_ctrl_av1_tile_group_entry

struct v4l2_ctrl_av1_tile_group_entry

__u32	tile_offset	Offset from the OBU data, i.e. where the coded tile data actually starts.
__u32	tile_size	Specifies the size in bytes of the coded tile. Equivalent to “TileSize” in AV1.
__u32	tile_row	Specifies the row of the current tile. Equivalent to “TileRow” in AV1.
__u32	tile_col	Specifies the column of the current tile. Equivalent to “TileColumn” in AV1.

type v4l2_av1_warp_model

AV1 Warp Model as described in section 3 “Symbols and abbreviated terms” of AV1.

V4L2_AV1_WARP_MODEL_IDENTITY	0	Warp model is just an identity transform.
V4L2_AV1_WARP_MODEL_TRANSLATION	1	Warp model is a pure translation.
V4L2_AV1_WARP_MODEL_ROTZOOM	2	Warp model is a rotation + symmetric zoom + translation.
V4L2_AV1_WARP_MODEL_AFFINE	3	Warp model is a general affine transform.

type v4l2_av1_reference_frame

AV1 Reference Frames as described in section 6.10.24 “Ref frames semantics” of AV1.

V4L2_AV1_REF_INTRA_FRAME	0	Intra Frame Reference.
V4L2_AV1_REF_LAST_FRAME	1	Last Frame Reference.
V4L2_AV1_REF_LAST2_FRAME	2	Last2 Frame Reference.
V4L2_AV1_REF_LAST3_FRAME	3	Last3 Frame Reference.
V4L2_AV1_REF_GOLDEN_FRAME	4	Golden Frame Reference.
V4L2_AV1_REF_BWDREF_FRAME	5	BWD Frame Reference.
V4L2_AV1_REF_ALTREF2_FRAME	6	ALTREF2 Frame Reference.
V4L2_AV1_REF_ALTREF_FRAME	7	ALTREF Frame Reference.

type v4l2_av1_global_motion

AV1 Global Motion parameters as described in section 6.8.17 “Global motion params semantics” of AV1.

struct v4l2_av1_global_motion

__u8	flags[V4L2_AV1_TOTAL_REFS_PER_FRAME]	A bitfield containing the flags per reference frame. See AV1 Global Motion Flags for more details.
enum v4l2_av1_warp_model	type[V4L2_AV1_TOTAL_REFS_PER_FRAME]	The type of global motion transform used.
__s32	params[V4L2_AV1_TOTAL_REFS_PER_FRAME][6]	This field has the same meaning as “gm_params” in AV1.
__u8	invalid	Bitfield indicating whether the global motion params are invalid for a given reference frame. See section 7.11.3.6 Setup shear process and the variable “warpValid”. Use V4L2_AV1_GLOBAL_MOTION_IS_INVALID(ref) to create a suitable mask.
__u8	reserved[3]	Applications and drivers must set this to zero.

AV1 Global Motion Flags

V4L2_AV1_GLOBAL_MOTION_FLAG_IS_GLOBAL	0x00000001	Specifies whether global motion parameters are present for a particular reference frame.
V4L2_AV1_GLOBAL_MOTION_FLAG_IS_ROT_ZOOM	0x00000002	Specifies whether a particular reference frame uses rotation and zoom global motion.
V4L2_AV1_GLOBAL_MOTION_FLAG_IS_TRANSLATION	0x00000004	Specifies whether a particular reference frame uses translation global motion

type v4l2_av1_frame_restoration_type

AV1 Frame Restoration Type.

V4L2_AV1_FRAME_RESTORE_NONE	0	No filtering is applied.
V4L2_AV1_FRAME_RESTORE_WIENER	1	Wiener filter process is invoked.
V4L2_AV1_FRAME_RESTORE_SGRPROJ	2	Self guided filter process is invoked.
V4L2_AV1_FRAME_RESTORE_SWITCHABLE	3	Restoration filter is swichtable.

type v4l2_av1_loop_restoration

AV1 Loop Restoration as described in section 6.10.15 “Loop restoration params semantics” of AV1.

struct v4l2_av1_loop_restoration

__u8	flags	See AV1 Loop Restoration Flags.
__u8	lr_unit_shift	Specifies if the luma restoration size should be halved.
__u8	lr_uv_shift	Specifies if the chroma size should be half the luma size.
__u8	reserved	Applications and drivers must set this to zero.
v4l2_av1_frame_restoration_type	frame_restoration_type[V4L2_AV1_NUM_PLANES_MAX]	Specifies the type of restoration used for each plane.
__u8	loop_restoration_size[V4L2_AV1_MAX_NUM_PLANES]	Specifies the size of loop restoration units in units of samples in the current plane.

AV1 Loop Restoration Flags

V4L2_AV1_LOOP_RESTORATION_FLAG_USES_LR	0x00000001	Retains the same meaning as UsesLr in AV1.
V4L2_AV1_LOOP_RESTORATION_FLAG_USES_CHROMA_LR	0x00000002	Retains the same meaning as UsesChromaLr in AV1.

type v4l2_av1_cdef

AV1 CDEF params semantics as described in section 6.10.14 “CDEF params semantics” of AV1.

struct v4l2_av1_cdef

__u8	damping_minus_3	Controls the amount of damping in the deringing filter.
__u8	bits	Specifies the number of bits needed to specify which CDEF filter to apply.
__u8	y_pri_strength[V4L2_AV1_CDEF_MAX]	Specifies the strength of the primary filter.
__u8	y_sec_strength[V4L2_AV1_CDEF_MAX]	Specifies the strength of the secondary filter.
__u8	uv_pri_strength[V4L2_AV1_CDEF_MAX]	Specifies the strength of the primary filter.
__u8	uv_sec_strength[V4L2_AV1_CDEF_MAX]	Specifies the strength of the secondary filter.

type v4l2_av1_segment_feature

AV1 segment features as described in section 3 “Symbols and abbreviated terms” of AV1.

V4L2_AV1_SEG_LVL_ALT_Q	0	Index for quantizer segment feature.
V4L2_AV1_SEG_LVL_ALT_LF_Y_V	1	Index for vertical luma loop filter segment feature.
V4L2_AV1_SEG_LVL_REF_FRAME	5	Index for reference frame segment feature.
V4L2_AV1_SEG_LVL_REF_SKIP	6	Index for skip segment feature.
V4L2_AV1_SEG_LVL_REF_GLOBALMV	7	Index for global mv feature.
V4L2_AV1_SEG_LVL_MAX	8	Number of segment features.

type v4l2_av1_segmentation

AV1 Segmentation params as defined in section 6.8.13 “Segmentation params semantics” of AV1.

struct v4l2_av1_segmentation

__u8	flags	See AV1 Segmentation Flags
__u8	last_active_seg_id	Indicates the highest numbered segment id that has some enabled feature. This is used when decoding the segment id to only decode choices corresponding to used segments.
__u8	feature_enabled[V4L2_AV1_MAX_SEGMENTS]	Bitmask defining which features are enabled in each segment. Use V4L2_AV1_SEGMENT_FEATURE_ENABLED to build a suitable mask.
__u16	feature_data[V4L2_AV1_MAX_SEGMENTS][V4L2_AV1_SEG_LVL_MAX]	Data attached to each feature. Data entry is only valid if the feature is enabled.

AV1 Segmentation Flags

V4L2_AV1_SEGMENTATION_FLAG_ENABLED	0x00000001	If set, indicates that this frame makes use of the segmentation tool. If not set, indicates that the frame does not use segmentation.
V4L2_AV1_SEGMENTATION_FLAG_UPDATE_MAP	0x00000002	If set, indicates that the segmentation map are updated during the decoding of this frame. If not set, indicates that the segmentation map from the previous frame is used.
V4L2_AV1_SEGMENTATION_FLAG_TEMPORAL_UPDATE	0x00000004	If set, indicates that the updates to the segmentation map are coded relative to the existing segmentation map. If not set, indicates that the new segmentation map is coded without reference to the existing segmentation map.
V4L2_AV1_SEGMENTATION_FLAG_UPDATE_DATA	0x00000008	If set, indicates that the updates to the segmentation map are coded relative to the existing segmentation map. If not set, indicates that the new segmentation map is coded without reference to the existing segmentation map.
V4L2_AV1_SEGMENTATION_FLAG_SEG_ID_PRE_SKIP	0x00000010	If set, indicates that the segment id will be read before the skip syntax element. If not set, indicates that the skip syntax element will be read first.

type v4l2_av1_loop_filter

AV1 Loop filter params as defined in section 6.8.10 “Loop filter semantics” of AV1.

struct v4l2_av1_loop_filter

__u8	flags	See AV1 Loop Filter flags for more details.
__u8	level[4]	An array containing loop filter strength values. Different loop filter strength values from the array are used depending on the image plane being filtered, and the edge direction (vertical or horizontal) being filtered.
__u8	sharpness	indicates the sharpness level. The loop_filter_level and loop_filter_sharpness together determine when a block edge is filtered, and by how much the filtering can change the sample values. The loop filter process is described in section 7.14 of AV1.
__u8	ref_deltas[V4L2_AV1_TOTAL_REFS_PER_FRAME]	contains the adjustment needed for the filter level based on the chosen reference frame. If this syntax element is not present, it maintains its previous value.
__u8	mode_deltas[2]	contains the adjustment needed for the filter level based on the chosen mode. If this syntax element is not present, it maintains its previous value.
__u8	delta_lf_res	specifies the left shift which should be applied to decoded loop filter delta values.

AV1 Loop Filter Flags

V4L2_AV1_LOOP_FILTER_FLAG_DELTA_ENABLED	0x00000001	If set, means that the filter level depends on the mode and reference frame used to predict a block. If not set, means that the filter level does not depend on the mode and reference frame.
V4L2_AV1_LOOP_FILTER_FLAG_DELTA_UPDATE	0x00000002	If set, means that additional syntax elements are present that specify which mode and reference frame deltas are to be updated. If not set, means that these syntax elements are not present.
V4L2_AV1_LOOP_FILTER_FLAG_DELTA_LF_PRESENT	0x00000004	Specifies whether loop filter delta values are present
V4L2_AV1_LOOP_FILTER_FLAG_DELTA_LF_MULTI	0x00000008	A value equal to 1 specifies that separate loop filter deltas are sent for horizontal luma edges, vertical luma edges, the U edges, and the V edges. A value of delta_lf_multi equal to 0 specifies that the same loop filter delta is used for all edges.

type v4l2_av1_quantization

AV1 Quantization params as defined in section 6.8.11 “Quantization params semantics” of AV1.

struct v4l2_av1_quantization

__u8	flags	See AV1 Loop Filter flags for more details.
__u8	base_q_idx	Indicates the base frame qindex. This is used for Y AC coefficients and as the base value for the other quantizers.
__u8	delta_q_y_dc	Indicates the Y DC quantizer relative to base_q_idx.
__u8	delta_q_u_dc	Indicates the U DC quantizer relative to base_q_idx.
__u8	delta_q_u_ac	Indicates the U AC quantizer relative to base_q_idx.
__u8	delta_q_v_dc	Indicates the V DC quantizer relative to base_q_idx.
__u8	delta_q_v_ac	Indicates the V AC quantizer relative to base_q_idx.
__u8	qm_y	Specifies the level in the quantizer matrix that should be used for luma plane decoding.
__u8	qm_u	Specifies the level in the quantizer matrix that should be used for chroma U plane decoding.
__u8	qm_v	Specifies the level in the quantizer matrix that should be used for chroma V plane decoding.
__u8	delta_q_res	Specifies the left shift which should be applied to decoded quantizer index delta values.

AV1 Quantization Flags

V4L2_AV1_QUANTIZATION_FLAG_DIFF_UV_DELTA	0x00000001	If set, indicates that the U and V delta quantizer values are coded separately. If not set, indicates that the U and V delta quantizer values share a common value.
V4L2_AV1_QUANTIZATION_FLAG_USING_QMATRIX	0x00000002	If set, specifies that the quantizer matrix will be used to compute quantizers.
V4L2_AV1_QUANTIZATION_FLAG_DELTA_Q_PRESENT	0x00000004	Specifies whether quantizer index delta values are present.

type v4l2_av1_tile_info

AV1 Tile info as defined in section 6.8.14 “Tile info semantics” of ref:av1.

struct v4l2_av1_tile_info

__u8	flags	See AV1 Tile Info flags for more details.
__u8	context_update_tile_id	Specifies which tile to use for the CDF update.
__u8	tile_cols	Specifies the number of tiles across the frame.
__u8	tile_rows	Specifies the number of tiles down the frame.
__u32	mi_col_starts[V4L2_AV1_MAX_TILE_COLS + 1]	An array specifying the start column (in units of 4x4 luma samples) for each tile across the image.
__u32	mi_row_starts[V4L2_AV1_MAX_TILE_ROWS + 1]	An array specifying the start row (in units of 4x4 luma samples) for each tile across the image.
__u32	width_in_sbs_minus_1[V4L2_AV1_MAX_TILE_COLS]	Specifies the width of a tile minus 1 in units of superblocks.
__u32	height_in_sbs_minus_1[V4L2_AV1_MAX_TILE_ROWS]	Specifies the height of a tile minus 1 in units of superblocks.
__u8	tile_size_bytes	Specifies the number of bytes needed to code each tile size.
__u8	reserved[3]	Applications and drivers must set this to zero.

AV1 Tile Info Flags

V4L2_AV1_TILE_INFO_FLAG_UNIFORM_TILE_SPACING

0x00000001

If set, means that the tiles are uniformly spaced across the frame. (In other words, all tiles are the same size except for the ones at the right and bottom edge which can be smaller). If not set means that the tile sizes are coded.

type v4l2_av1_frame_type

AV1 Frame Type

V4L2_AV1_KEY_FRAME	0	Key frame.
V4L2_AV1_INTER_FRAME	1	Inter frame.
V4L2_AV1_INTRA_ONLY_FRAME	2	Intra-only frame.
V4L2_AV1_SWITCH_FRAME	3	Switch frame.

type v4l2_av1_interpolation_filter

AV1 Interpolation Filter

V4L2_AV1_INTERPOLATION_FILTER_EIGHTTAP	0	Eight tap filter.
V4L2_AV1_INTERPOLATION_FILTER_EIGHTTAP_SMOOTH	1	Eight tap smooth filter.
V4L2_AV1_INTERPOLATION_FILTER_EIGHTTAP_SHARP	2	Eight tap sharp filter.
V4L2_AV1_INTERPOLATION_FILTER_BILINEAR	3	Bilinear filter.
V4L2_AV1_INTERPOLATION_FILTER_SWITCHABLE	4	Filter selection is signaled at the block level.

type v4l2_av1_tx_mode

AV1 Tx mode as described in section 6.8.21 “TX mode semantics” of AV1.

V4L2_AV1_TX_MODE_ONLY_4X4	0	The inverse transform will use only 4x4 transforms.
V4L2_AV1_TX_MODE_LARGEST	1	The inverse transform will use the largest transform size that fits inside the block.
V4L2_AV1_TX_MODE_SELECT	2	The choice of transform size is specified explicitly for each block.

V4L2_CID_STATELESS_AV1_FRAME (struct)

Represents a Frame Header OBU. See 6.8 “Frame Header OBU semantics” of AV1 for more details.

type v4l2_ctrl_av1_frame

struct v4l2_ctrl_av1_frame

struct v4l2_av1_tile_info	tile_info	Tile info
struct v4l2_av1_quantization	quantization	Quantization parameters.
__u8	superres_denom	The denominator for the upscaling ratio.
struct v4l2_av1_segmentation	segmentation	Segmentation parameters.
struct v4l2_av1_loop_filter	loop_filter	Loop filter params
struct v4l2_av1_cdef	cdef	CDEF params
__u8	skip_mode_frame[2]	Specifies the frames to use for compound prediction when skip_mode is equal to 1.
__u8	primary_ref_frame	Specifies which reference frame contains the CDF values and other state that should be loaded at the start of the frame.
struct v4l2_av1_loop_restoration	loop_restoration	Loop restoration parameters.
struct v4l2_av1_global_motion	global_motion	Global motion parameters.
__u32	flags	See AV1 Frame flags for more details.
enum v4l2_av1_frame_type	frame_type	Specifies the AV1 frame type
__u32	order_hint	Specifies OrderHintBits least significant bits of the expected output order for this frame.
__u32	upscaled_width	The upscaled width.
enum v4l2_av1_interpolation_filter	interpolation_filter	Specifies the filter selection used for performing inter prediction.
enum v4l2_av1_tx_mode	tx_mode	Specifies how the transform size is determined.
__u32	frame_width_minus_1	Add 1 to get the frame’s width.
__u32	frame_height_minus_1	Add 1 to get the frame’s height.
__u16	render_width_minus_1	Add 1 to get the render width of the frame in luma samples.
__u16	render_height_minus_1	Add 1 to get the render height of the frame in luma samples.
__u32	current_frame_id	Specifies the frame id number for the current frame. Frame id numbers are additional information that do not affect the decoding process, but provide decoders with a way of detecting missing reference frames so that appropriate action can be taken.
__u8	buffer_removal_time[V4L2_AV1_MAX_OPERATING_POINTS]	Specifies the frame removal time in units of DecCT clock ticks counted from the removal time of the last random access point for operating point opNum.
__u8	reserved[4]	Applications and drivers must set this to zero.
__u32	order_hints[V4L2_AV1_TOTAL_REFS_PER_FRAME]	Specifies the expected output order hint for each reference frame. This field corresponds to the OrderHints variable from the specification (section 5.9.2 “Uncompressed header syntax”). As such, this is only used for non-intra frames and ignored otherwise. order_hints[0] is always ignored.
__u64	reference_frame_ts[V4L2_AV1_TOTAL_REFS_PER_FRAME]	The V4L2 timestamp for each of the reference frames enumerated in enum v4l2_av1_reference_frame starting at V4L2_AV1_REF_LAST_FRAME. This represents the state of reference slot as described in the spec and updated by userland through the “Reference frame update process” in section 7.20 The timestamp refers to the timestamp field in struct v4l2_buffer. Use the v4l2_timeval_to_ns() function to convert the struct timeval in struct v4l2_buffer to a __u64.
__s8	ref_frame_idx[V4L2_AV1_REFS_PER_FRAME]	An index into reference_frame_ts representing the ordered list of references used by inter-frame. Matches the bitstream syntax element of the same name.
__u8	refresh_frame_flags	Contains a bitmask that specifies which reference frame slots will be updated with the current frame after it is decoded.

AV1 Frame Flags

V4L2_AV1_FRAME_FLAG_SHOW_FRAME	0x00000001	If set, specifies that this frame should be immediately output once decoded. If not set, specifies that this frame should not be immediately output; it may be output later if a later uncompressed header uses show_existing_frame equal to 1.
V4L2_AV1_FRAME_FLAG_SHOWABLE_FRAME	0x00000002	If set, specifies that the frame may be output using the show_existing_frame mechanism. If not set, specifies that this frame will not be output using the show_existing_frame mechanism.
V4L2_AV1_FRAME_FLAG_ERROR_RESILIENT_MODE	0x00000004	Specifies whether error resilient mode is enabled.
V4L2_AV1_FRAME_FLAG_DISABLE_CDF_UPDATE	0x00000008	Specifies whether the CDF update in the symbol decoding process should be disabled.
V4L2_AV1_FRAME_FLAG_ALLOW_SCREEN_CONTENT_TOOLS	0x00000010	If set, indicates that intra blocks may use palette encoding. If not set, indicates that palette encoding is never used.
V4L2_AV1_FRAME_FLAG_FORCE_INTEGER_MV	0x00000020	If set, specifies that motion vectors will always be integers. If not set, specifies that motion vectors can contain fractional bits.
V4L2_AV1_FRAME_FLAG_ALLOW_INTRABC	0x00000040	If set, indicates that intra block copy may be used in this frame. If not set, indicates that intra block copy is not allowed in this frame.
V4L2_AV1_FRAME_FLAG_USE_SUPERRES	0x00000080	If set, indicates that upscaling is needed.
V4L2_AV1_FRAME_FLAG_ALLOW_HIGH_PRECISION_MV	0x00000100	If set, specifies that motion vectors are specified to eighth pel precision. If not set, specifies that motion vectors are specified to quarter pel precision;
V4L2_AV1_FRAME_FLAG_IS_MOTION_MODE_SWITCHABLE	0x00000200	If not set, specifies that only the SIMPLE motion mode will be used.
V4L2_AV1_FRAME_FLAG_USE_REF_FRAME_MVS	0x00000400	If set specifies that motion vector information from a previous frame can be used when decoding the current frame. If not set, specifies that this information will not be used.
V4L2_AV1_FRAME_FLAG_DISABLE_FRAME_END_UPDATE_CDF	0x00000800	If set indicates that the end of frame CDF update is disabled. If not set, indicates that the end of frame CDF update is enabled
V4L2_AV1_FRAME_FLAG_ALLOW_WARPED_MOTION	0x00001000	If set, indicates that the syntax element motion_mode may be present, if not set, indicates that the syntax element motion_mode will not be present.
V4L2_AV1_FRAME_FLAG_REFERENCE_SELECT	0x00002000	If set, specifies that the mode info for inter blocks contains the syntax element comp_mode that indicates whether to use single or compound reference prediction. If not set, specifies that all inter blocks will use single prediction.
V4L2_AV1_FRAME_FLAG_REDUCED_TX_SET	0x00004000	If set, specifies that the frame is restricted to a reduced subset of the full set of transform types.
V4L2_AV1_FRAME_FLAG_SKIP_MODE_ALLOWED	0x00008000	This flag retains the same meaning as SkipModeAllowed in AV1.
V4L2_AV1_FRAME_FLAG_SKIP_MODE_PRESENT	0x00010000	If set, specifies that the syntax element skip_mode will be present, if not set, specifies that skip_mode will not be used for this frame.
V4L2_AV1_FRAME_FLAG_FRAME_SIZE_OVERRIDE	0x00020000	If set, specifies that the frame size will either be specified as the size of one of the reference frames, or computed from the frame_width_minus_1 and frame_height_minus_1 syntax elements. If not set, specifies that the frame size is equal to the size in the sequence header.
V4L2_AV1_FRAME_FLAG_BUFFER_REMOVAL_TIME_PRESENT	0x00040000	If set, specifies that buffer_removal_time is present. If not set, specifies that buffer_removal_time is not present.
V4L2_AV1_FRAME_FLAG_FRAME_REFS_SHORT_SIGNALING	0x00080000	If set, indicates that only two reference frames are explicitly signaled. If not set, indicates that all reference frames are explicitly signaled.

V4L2_CID_STATELESS_AV1_FILM_GRAIN (struct)

Represents the optional film grain parameters. See section 6.8.20 “Film grain params semantics” of AV1 for more details.

type v4l2_ctrl_av1_film_grain

struct v4l2_ctrl_av1_film_grain

__u8	flags	See AV1 Film Grain Flags.
__u8	cr_mult	Represents a multiplier for the cr component used in derivation of the input index to the cr component scaling function.
__u16	grain_seed	Specifies the starting value for the pseudo-random numbers used during film grain synthesis.
__u8	film_grain_params_ref_idx	Indicates which reference frame contains the film grain parameters to be used for this frame.
__u8	num_y_points	Specifies the number of points for the piece-wise linear scaling function of the luma component.
__u8	point_y_value[V4L2_AV1_MAX_NUM_Y_POINTS]	Represents the x (luma value) coordinate for the i-th point of the piecewise linear scaling function for luma component. The values are signaled on the scale of 0..255. In case of 10 bit video, these values correspond to luma values divided by 4. In case of 12 bit video, these values correspond to luma values divided by 16.
__u8	point_y_scaling[V4L2_AV1_MAX_NUM_Y_POINTS]	Represents the scaling (output) value for the i-th point of the piecewise linear scaling function for luma component.
__u8	num_cb_points	Specifies the number of points for the piece-wise linear scaling function of the cb component.
__u8	point_cb_value[V4L2_AV1_MAX_NUM_CB_POINTS]	Represents the x coordinate for the i-th point of the piece-wise linear scaling function for cb component. The values are signaled on the scale of 0..255.
__u8	point_cb_scaling[V4L2_AV1_MAX_NUM_CB_POINTS]	Represents the scaling (output) value for the i-th point of the piecewise linear scaling function for cb component.
__u8	num_cr_points	Represents the number of points for the piece-wise linear scaling function of the cr component.
__u8	point_cr_value[V4L2_AV1_MAX_NUM_CR_POINTS]	Represents the x coordinate for the i-th point of the piece-wise linear scaling function for cr component. The values are signaled on the scale of 0..255.
__u8	point_cr_scaling[V4L2_AV1_MAX_NUM_CR_POINTS]	Represents the scaling (output) value for the i-th point of the piecewise linear scaling function for cr component.
__u8	grain_scaling_minus_8	Represents the shift - 8 applied to the values of the chroma component. The grain_scaling_minus_8 can take values of 0..3 and determines the range and quantization step of the standard deviation of film grain.
__u8	ar_coeff_lag	Specifies the number of auto-regressive coefficients for luma and chroma.
__u8	ar_coeffs_y_plus_128[V4L2_AV1_AR_COEFFS_SIZE]	Specifies auto-regressive coefficients used for the Y plane.
__u8	ar_coeffs_cb_plus_128[V4L2_AV1_AR_COEFFS_SIZE]	Specifies auto-regressive coefficients used for the U plane.
__u8	ar_coeffs_cr_plus_128[V4L2_AV1_AR_COEFFS_SIZE]	Specifies auto-regressive coefficients used for the V plane.
__u8	ar_coeff_shift_minus_6	Specifies the range of the auto-regressive coefficients. Values of 0, 1, 2, and 3 correspond to the ranges for auto-regressive coefficients of [-2, 2), [-1, 1), [-0.5, 0.5) and [-0.25, 0.25) respectively.
__u8	grain_scale_shift	Specifies how much the Gaussian random numbers should be scaled down during the grain synthesis process.
__u8	cb_mult	Represents a multiplier for the cb component used in derivation of the input index to the cb component scaling function.
__u8	cb_luma_mult	Represents a multiplier for the average luma component used in derivation of the input index to the cb component scaling function..
__u8	cr_luma_mult	Represents a multiplier for the average luma component used in derivation of the input index to the cr component scaling function.
__u16	cb_offset	Represents an offset used in derivation of the input index to the cb component scaling function.
__u16	cr_offset	Represents an offset used in derivation of the input index to the cr component scaling function.
__u8	reserved[4]	Applications and drivers must set this to zero.

AV1 Film Grain Flags

V4L2_AV1_FILM_GRAIN_FLAG_APPLY_GRAIN	0x00000001	If set, specifies that film grain should be added to this frame. If not set, specifies that film grain should not be added.
V4L2_AV1_FILM_GRAIN_FLAG_UPDATE_GRAIN	0x00000002	If set, means that a new set of parameters should be sent. If not set, specifies that the previous set of parameters should be used.
V4L2_AV1_FILM_GRAIN_FLAG_CHROMA_SCALING_FROM_LUMA	0x00000004	If set, specifies that the chroma scaling is inferred from the luma scaling.
V4L2_AV1_FILM_GRAIN_FLAG_OVERLAP	0x00000008	If set, indicates that the overlap between film grain blocks shall be applied. If not set, indicates that the overlap between film grain blocks shall not be applied.
V4L2_AV1_FILM_GRAIN_FLAG_CLIP_TO_RESTRICTED_RANGE	0x00000010	If set, indicates that clipping to the restricted (studio, i.e. limited) range shall be applied to the sample values after adding the film grain (see the semantics for color_range for an explanation of studio swing). If not set, indicates that clipping to the full range shall be applied to the sample values after adding the film grain.