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.
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.
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.
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.
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”.
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.
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

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.
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_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  
__u16 frame_num  
__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.
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.
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.
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.
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_scaling factor Vertical scale.
__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.
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.
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.
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.
v4l2_vp8_quantization
struct v4l2_vp8_quantization
__u8 y_ac_qi Luma AC coefficient table index.
__s8 y_dc_delta Luma DC delta vaue.
__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.
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.
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.
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.
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.