[FFmpeg-devel] [PATCH] libavformat/mxfenc: Allow more bitrates for NTSC IMX50

[Tomas Härdin]

tis 2019-08-13 klockan 22:03 +0200 skrev Thomas Mundt:
> Hi,
> 
> attached patch fixes ticket #8077.
> Please comment.

Probably OK, bitrates lower than 50000000 are fine in D-10 according to
S356m.

> } else if ((sc->video_bit_rate >= 49999840) && (sc->video_bit_rate <=
> 50000000) && (mxf->time_base.den != 25)) {

You could drop the extra parentheses, else it should be fine.

The real fix is of course to add an explicit CBR mode to lavc, but
that's a bit more involved than this fix. Removing the padding from the
old code was probably a mistake, we should come up with a better
solution. Baptiste?

It bears repeating that S356m explicitly allows VBR (still intra-only)
so long as the frames are no larger than 250000 and 208541 for PAL and
NTSC respectively. I don't recall whether the MXF file itself needs to
be CBR (via KLV fill).

/Tomas