On Thu, Feb 20, 2020 at 11:22:33AM +0000, Gaullier Nicolas wrote:
> > De : ffmpeg-devel <ffmpeg-devel-boun...@ffmpeg.org> De la part de Michael
> > Niedermayer
> > Envoyé : vendredi 7 février 2020 23:39
> > À : FFmpeg development discussions and patches <ffmpeg-devel@ffmpeg.org>
> > Objet : Re: [FFmpeg-devel] [PATCH v7 3/3] avcodec/mpeg12dec: Add CPB coded
> > side data
> >
> > On Wed, Jan 15, 2020 at 12:42:13AM +0100, Nicolas Gaullier wrote:
> > > This fixes mpeg2video stream copies to mpeg muxer like this:
> > > ffmpeg -i xdcamhd.mxf -c:v copy output.mpg
> > > ---
> > > libavcodec/mpeg12dec.c | 7 +++++++
> > > tests/ref/fate/mxf-probe-d10 | 3 +++
> > > tests/ref/fate/ts-demux | 2 +-
> > > 3 files changed, 11 insertions(+), 1 deletion(-)
> > >
> > > diff --git a/libavcodec/mpeg12dec.c b/libavcodec/mpeg12dec.c index
> > > 17f9495a1d..48ac14fafa 100644
> > > --- a/libavcodec/mpeg12dec.c
> > > +++ b/libavcodec/mpeg12dec.c
> > > @@ -1398,6 +1398,7 @@ static void
> > > mpeg_decode_sequence_extension(Mpeg1Context *s1)
> > > MpegEncContext *s = &s1->mpeg_enc_ctx;
> > > int horiz_size_ext, vert_size_ext;
> > > int bit_rate_ext;
> > > + AVCPBProperties *cpb_props;
> > >
> > > skip_bits(&s->gb, 1); /* profile and level esc*/
> > > s->avctx->profile = get_bits(&s->gb, 3);
> > > @@ -1429,6 +1430,12 @@ static void
> > > mpeg_decode_sequence_extension(Mpeg1Context *s1)
> > > ff_dlog(s->avctx, "sequence extension\n");
> > > s->codec_id = s->avctx->codec_id = AV_CODEC_ID_MPEG2VIDEO;
> > >
> > > + if (cpb_props = ff_add_cpb_side_data(s->avctx)) {
> > > + cpb_props->buffer_size = FFMAX(cpb_props->buffer_size,
> > > s->avctx->rc_buffer_size);
> > > + if (s->bit_rate != 0x3FFFF*400)
> > > + cpb_props->max_bitrate = FFMAX(cpb_props->max_bitrate,
> > > s->bit_rate);
> > > + }
> >
> > why does this not export exactly the numbers as read from the header?
> >
> > thx
> The header values are expressed in units of 400bit/s, and the native value
> 0x3FFFF is reserved, in case of MPEG-1 (but the code is shared), for vbr
> signalling.
> This is not very nice to read, but this is how it is implemented in current
> code.you misunderstand, why do you take the maximum of several things instead of exporting the value from the header ? Thanks [...] -- Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB "I am not trying to be anyone's saviour, I'm trying to think about the future and not be sad" - Elon Musk
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