Add gray16 as a supported v4l2 input format.
Add yvu410 as a supported v4l2 input format.
Revert "swfenc: use av_get_audio_frame_duration() instead of AVCodecContext.frame_size"

This reverts commit 620b88a302d522f71a6a95aff500cf7bd8520043.

Fixes ticket #2272.

Conflicts:
	libavformat/swfenc.c
h264: avoid calling get_format() multiple times

Some applications do not like that.
Fixes VDA
Reduces noise for VDPAU

Tested-by: Guillaume POIRIER <poirierg@gmail.com>
Tested-by: Carl Eugen Hoyos <cehoyos@ag.or.at>
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>