[FFmpeg-devel] [PATCH 3/6] avcodec/h264_slice: export S12M timecode side data

lance.lmwang at gmail.com lance.lmwang at gmail.com
Wed Jul 15 18:52:00 EEST 2020


On Wed, Jul 15, 2020 at 04:16:38PM +0100, Kieran Kunhya wrote:
> If you look a few lines above, we already set the timecode side data.
> 

are you saying av_frame_new_side_data() above?  that's total different, in fact,
I'm try to use the same way with ff_add_cpb_side_data(), it'll put TC in the codec
level: avctx->nb_coded_side_data instead of frame level. By this way, I can export
the correct TC in the following patch for movenc, dv file format. Please refer to:
libavformat/utils.c line 4154 add_coded_side_data() is used to copy all AVPacketSideData
side data to st level. If someone have better way to reuse the frame side
data, please give your advice.

> Sent from my mobile device
> 
> On Wed, 15 Jul 2020, 14:44 , <lance.lmwang at gmail.com> wrote:
> 
> > On Wed, Jul 15, 2020 at 09:16:16AM +0100, Kieran Kunhya wrote:
> > > On Wed, 15 Jul 2020 at 02:19, <lance.lmwang at gmail.com> wrote:
> > >
> > > > On Wed, Jul 15, 2020 at 12:54:35AM +0100, Kieran Kunhya wrote:
> > > > > On Wed, 15 Jul 2020 at 00:36, <lance.lmwang at gmail.com> wrote:
> > > > >
> > > > > > From: Limin Wang <lance.lmwang at gmail.com>
> > > > > >
> > > > > > Signed-off-by: Limin Wang <lance.lmwang at gmail.com>
> > > > > > ---
> > > > > >  libavcodec/h264_slice.c | 10 ++++++++++
> > > > > >  1 file changed, 10 insertions(+)
> > > > > >
> > > > > > diff --git a/libavcodec/h264_slice.c b/libavcodec/h264_slice.c
> > > > > > index c7b2764..db720de 100644
> > > > > > --- a/libavcodec/h264_slice.c
> > > > > > +++ b/libavcodec/h264_slice.c
> > > > > > @@ -1307,6 +1307,7 @@ static int
> > h264_export_frame_props(H264Context
> > > > *h)
> > > > > >      if (h->sei.picture_timing.timecode_cnt > 0) {
> > > > > >          uint32_t *tc_sd;
> > > > > >          char tcbuf[AV_TIMECODE_STR_SIZE];
> > > > > > +        uint32_t *s12m_sd;
> > > > > >
> > > > > >          AVFrameSideData *tcside = av_frame_new_side_data(out,
> > > > > >
> > > > > > AV_FRAME_DATA_S12M_TIMECODE,
> > > > > > @@ -1316,6 +1317,12 @@ static int
> > h264_export_frame_props(H264Context
> > > > *h)
> > > > > >
> > > > > >          tc_sd = (uint32_t*)tcside->data;
> > > > > >          tc_sd[0] = h->sei.picture_timing.timecode_cnt;
> > > > > > +        if (h->avctx->export_side_data &
> > > > AV_CODEC_EXPORT_DATA_S12M_TC) {
> > > > > > +            s12m_sd = ff_add_s12m_timecode_side_data(h->avctx);
> > > > > > +            if (!s12m_sd)
> > > > > > +                return AVERROR(ENOMEM);
> > > > > > +            s12m_sd[0] = tc_sd[0];
> > > > > > +        }
> > > > > >
> > > > > >          for (int i = 0; i < tc_sd[0]; i++) {
> > > > > >              int drop =
> > h->sei.picture_timing.timecode[i].dropframe;
> > > > > > @@ -1325,6 +1332,9 @@ static int
> > h264_export_frame_props(H264Context
> > > > *h)
> > > > > >              int   ff = h->sei.picture_timing.timecode[i].frame;
> > > > > >
> > > > > >              tc_sd[i + 1] =
> > av_timecode_get_smpte(h->avctx->framerate,
> > > > > > drop, hh, mm, ss, ff);
> > > > > > +            if (h->avctx->export_side_data &
> > > > > > AV_CODEC_EXPORT_DATA_S12M_TC) {
> > > > > > +                s12m_sd[i + 1] = tc_sd[i + 1];
> > > > > > +            }
> > > > > >              av_timecode_make_smpte_tc_string(tcbuf, tc_sd[i + 1],
> > 0);
> > > > > >              av_dict_set(&out->metadata, "timecode", tcbuf, 0);
> > > > > >          }
> > > > > > --
> > > > >
> > > > >
> > > > > Does this not duplicate the existing logic?
> > > >
> > > > It's export packet timecode sidedata, so that you can export the TC
> > side
> > > > data to stream
> > > > level. patch#5 show the command how to use it, before the patch, you
> > had
> > > > to input timecode
> > > > to export the TC to tmcd track for mp4. Please give advise if you have
> > > > better way to get it,
> > > > thanks.
> > > >
> > >
> > > I don't understand, timecode side data is already exported from H.264.
> > > Why do you need to create two side datas?
> >
> > yes, it's better to have a function to copy the side data from frame to
> > packet level, I'm not sure where is the proper place and how to make the
> > frame and packet is sync by the timecode. Maybe libavcodec/encode.c is a
> > good place, but it didn't make sense if the video is copy directly.
> >
> > >
> > > Kieran
> > > _______________________________________________
> > > ffmpeg-devel mailing list
> > > ffmpeg-devel at ffmpeg.org
> > > https://ffmpeg.org/mailman/listinfo/ffmpeg-devel
> > >
> > > To unsubscribe, visit link above, or email
> > > ffmpeg-devel-request at ffmpeg.org with subject "unsubscribe".
> >
> > --
> > Thanks,
> > Limin Wang
> > _______________________________________________
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> >
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-- 
Thanks,
Limin Wang


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