Because libavdevice/v4l2 is a demuxer, it makes sense to look for
decoders instead of encoders when listing the formats supported by the
device.
Signed-off-by: Stefano Sabatini <stefasab@gmail.com>
The cpia video decoder is intended to be used with the v4l2 demuxer.
There are some small changes to the v4l2 demuxer to support the
variable frame length of the format.
Fixes ticket #1537
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>