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• Convert MPEG4/H264 I-Frame (IDR) from RTP stream to JPG ? [on hold]

  10 mars 2017, par ioan ghip

  I’m playing around with MPEG4/H264 received over RTP and I can successfully detect and receive I-Frames. My plan is to convert the I-Frames to JPG and show them on the screen (ultimately I want to implement basic rtp support for Roku player).
  Where do I start ? Any code examples or algorithm description on how to convert the the video frames to an image ?

• avcodec/ffv1dec : fix some unsupported pix_fmt

  13 juin 2016, par Jérôme Martinez

  avcodec/ffv1dec : fix some unsupported pix_fmt
  When checking pix_fmt mapping, some bitstreams are mapped to an
  
  incorrect pix_fmt instead of being rejected (ENOSYS).
  
  Actually, such bitstreams are not supported (FFmpeg encoder does not
  
  produce such bitstream, such bitstream may come only from another
  
  encoder for the moment).
   JPEG 2000 RCT 11/13/15/16 bit depths are mapped to a 8-bit FFmpeg
  
  pix_fmt (e.g. bgr0), which is not expected.
  
   JPEG 2000 RCT 9/10/12/14 bit depths with alpha are mapped to a
  
  FFmpeg pix_fmt without alpha (e.g. AV_PIX_FMT_GBRP9 for 9-bit with
  
  alpha), which is not expected.
  The order for choosing the pix_fmt is changed to the one used by YCbCr
  
  selection (<=8 bit first).
  
  " && !f->transparency" is added to the other lines.
  Signed-off-by : Michael Niedermayer <michael@niedermayer.cc>
  

  • [DH] libavcodec/ffv1dec.c

• -use_wallclock_as_timestamps adds delay in live stream

  2 novembre 2020, par Arikael

  We have a livestream (MPEG-TS with RTP), which we currently, for testing purposes, replay with tcpreplay.

  


  Our mpeg-ts stream consists of 4 streams (codec details omitted for brevity).

  


  Stream #0:2: Video: h264
Stream #0:1: Audio: mp2
Stream #0:4: Data: bin_data ([6][0][0][0] / 0x0006)
Strean #0:3: Data: bin_data (FBID / 0x4494246)
Stream #0:0: Data: klv (KLVA / 0x41564C4B)


  


  Sometimes the stream indexes are different (like audio stream being stream 0 and so on, I don't know if thats normal behavior)

  


  What we currently try is just to get the stream and copy it with ffmpeg, like

  


  ffmpeg -nostdin -hide_banner -i rtp://239.0.0.2:3000 -map 0 -codec copy -f rtp_mpegts rtp://239.0.0.1:2000`


  


  This leads to the error Application provided invalid, non monotonically incereasing dts to muxer in stream 0: [NUMBER] >= 0

  


  It always says stream 0 no matter what stream 0 contains.

  


  if I add use_wallclock_as_timestamps it works but adds a delay (compared to a video directly streamed from 239.0.0.2:3000 of 10seconds which are never caught up.

  


  If I set the output format to mpegts instead of rpt_mpegts it works as expected, the same I if don't map the KLVA and FBID stream.

  


  Is this behavior expected (because of wallclock) or what can I do to either use_wallclock_as_timestamps without delay or get rid of the error above ?