6. Vaio Picturebook Motion Eye Camera Driver

Copyright © 2001-2004 Stelian Pop <stelian@popies.net>

Copyright © 2001-2002 Alcôve <www.alcove.com>

Copyright © 2000 Andrew Tridgell <tridge@samba.org>

6.1. Private API

The driver supports frame grabbing with the video4linux API, so all video4linux tools (like xawtv) should work with this driver.

Besides the video4linux interface, the driver has a private interface for accessing the Motion Eye extended parameters (camera sharpness, agc, video framerate), the snapshot and the MJPEG capture facilities.

This interface consists of several ioctls (prototypes and structures can be found in include/linux/meye.h):

MEYEIOC_G_PARAMS and MEYEIOC_S_PARAMS
Get and set the extended parameters of the motion eye camera. The user should always query the current parameters with MEYEIOC_G_PARAMS, change what he likes and then issue the MEYEIOC_S_PARAMS call (checking for -EINVAL). The extended parameters are described by the meye_params structure.
MEYEIOC_QBUF_CAPT
Queue a buffer for capture (the buffers must have been obtained with a VIDIOCGMBUF call and mmap’ed by the application). The argument to MEYEIOC_QBUF_CAPT is the buffer number to queue (or -1 to end capture). The first call to MEYEIOC_QBUF_CAPT starts the streaming capture.
MEYEIOC_SYNC
Takes as an argument the buffer number you want to sync. This ioctl blocks until the buffer is filled and ready for the application to use. It returns the buffer size.
MEYEIOC_STILLCAPT and MEYEIOC_STILLJCAPT
Takes a snapshot in an uncompressed or compressed jpeg format. This ioctl blocks until the snapshot is done and returns (for jpeg snapshot) the size of the image. The image data is available from the first mmap’ed buffer.

Look at the ‘motioneye’ application code for an actual example.