[FFmpeg-devel] [RFC PATCH 0/3] Propagate PRFT side data

[Clément Péron]

Dear FFMpeg contributors,

I'm new to the FFMpeg code base and audio/video sync world, so forgive me in
advance If my questions are a bit dumb.

I have a project where I need to synchronize multiple RTSP cameras with other
network sensors (sync with NTP or PTP).
In my case, I used Ffmpeg to decode the RTSP stream and then output the rawvideo
to the stdout pipe.

After looking in the RTPdec, I found multiple timestamps PST, DTS and also the
PRFT (Producer Reference Timestamp). In my case the PRFT seems the correct one.

After several tests and diggs, I found that the AV_PKT_DATA_PRFT produce by the
RTSP Demux doesn't seems to be forwarded to the encoder/decoder, nor to the
final Muxer.

So I have multiple question:

Is the forward of the AV_PKT_DATA_PRFT the correct solution?

I saw also that Dashenc and Movenc use this Side data but how do they get it?

Actually I have a dirty hack to output PRFT on the stdout, is there something
"more standard" to communicate between Ffmpeg and a python script?

Thanks for your help,
Clément

Clément Péron (3):
  frame: decode: propagate PRFT side data packet to frame
  avcodec: rawenc: Forward PRFT frame data to packet
  HACK: avformat: rawenc: allow to output a raw PRFT

 libavcodec/decode.c      |   1 +
 libavcodec/rawenc.c      |  12 ++++
 libavfilter/f_sidedata.c |   1 +
 libavformat/rawenc.c     | 122 +++++++++++++++++++++++++++++++++++++++
 libavutil/frame.c        |   1 +
 libavutil/frame.h        |   4 ++
 6 files changed, 141 insertions(+)

-- 
2.42.0