pcm-dvd: remove redundant log message

Signed-off-by: Paul B Mahol <onemda@gmail.com>
pcm-dvd: use av_freep()

Signed-off-by: Paul B Mahol <onemda@gmail.com>
Read h264 headers from v4l2 to allow stream-copying.

Fixes ticket #2882.
Analyzed and tested by William C Bonner.