avfilter/vf_separatefields: do not reset pts to 0

Signed-off-by: Paul B Mahol <onemda@gmail.com>
avfilter/vsrc_testsrc: smpte(hd)bars: use yuv directly

Also set color space.

Signed-off-by: Paul B Mahol <onemda@gmail.com>
avformat/avr: use ff_get_pcm_codec_id()

Signed-off-by: Paul B Mahol <onemda@gmail.com>