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• FFMPEG : How are the parsers providing input bit stream to the decoder

  24 décembre 2013, par Zax

  I'm having a video decoder integrated into FFMPEG. For this decoder i have a parser that reads data from the input bit stream (Elementary stream) and provide the decoder with the data whenever needed. I'm using fread() function in my parser to read the input bit stream.

  However, when i see the parsers of other available decoder in the libavcodec/ directory, none of them seems to have a fread in them. Tried to figure out this mechanism by debugging the code, but didn't get even a clue regrading the same. So i request if anyone can please provide some explanation regarding how the decoder is getting the required data even though its parsers doesn't seem to have any fread ? I mean what is the mechanish being used here to read data from the input file.

  Any suggestions/answers regarding the same will be really helpful to me. Kindly do the needful as it can help many people reading this post. Thanks in advance.

  —Regards

• nutenc/write_index : warn if 2 consecutive keyframes have the same PTS and discard...

  22 décembre 2013, par Michael Niedermayer

  nutenc/write_index : warn if 2 consecutive keyframes have the same PTS and discard the 2nd
  This fixes an assertion failure and regression and restores previous behaviour
  
  Fixes Ticket3197
  An alternative would be to fail hard in this case and refuse to mux such data.
  Signed-off-by : Michael Niedermayer <michaelni@gmx.at>
  

  • [DH] libavformat/nutenc.c

• RTP Streaming with ffmpeg : server streaming, client failing

  27 novembre 2013, par Christoph Kuhr

  I compiled ffmpeg and x264 myself.

  x264 version :

   #define X264_REV 2377
  
   #define X264_REV_DIFF 0
  
   #define X264_VERSION " r2377 1ca7bb9"
  
   #define X264_POINTVER "0.140.2377 1ca7bb9"

  ffmpeg version : 0.11.4
  ffmpeg configuration :

   --enable-x11grab --enable-pthreads --enable-libfaac --enable-libxvid --enable-libx264 --enable-libv4l2 --enable-libmp3lame --enable-libpulse --enable-gpl --enable-nonfree --disable-yasm

  streaming server call :

  ffmpeg -f x11grab -s 1600x900 -framerate 50 -i :0.0 -vcodec libx264 -threads 4 -preset ultrafast -crf 0 -q:v 1 -b:v 8M -an -f rtp rtp://192.168.188.30:8710
  
  
  
  ...
  
  
  
   Output #0, rtp, to 'rtp://192.168.188.30:8710':
  
    Metadata:
  
      encoder         : Lavf54.6.100
  
      Stream #0:0: Video: h264, yuv420p, 1600x900, q=-1--1, 8000 kb/s, 90k tbn, 50 tbc
  
  Stream mapping:
  
    Stream #0:0 -> #0:0 (rawvideo -> libx264)
  
  SDP:
  
  v=0
  
  o=- 0 0 IN IP4 127.0.0.1
  
  s=No Name
  
  c=IN IP4 192.168.188.30
  
  t=0 0
  
  a=tool:libavformat 54.6.100
  
  m=video 8710 RTP/AVP 96
  
  b=AS:8000
  
  a=rtpmap:96 H264/90000
  
  a=fmtp:96 packetization-mode=1

  Everything looks good so far...

  Now the problem.
  I create foo.sdp from the SDP output of the server and try to playback the stream with ffmpeg ffplay foo.sdp. ffplay fails with the following error :

   [sdp @ 0x7f5e0c0008c0] decoding for stream 0 failed
  
   [sdp @ 0x7f5e0c0008c0] Could not find codec parameters (Video: h264)
  
   [sdp @ 0x7f5e0c0008c0] Estimating duration from bitrate, this may be inaccurate
  
   gameserver.sdp: could not find codec parameters

  If I try the same with VLC, it also fails, but with the different error :

    [0x7f3278c045b8] live555 demux error: no data received in 10s, aborting

  Look like different reasons. But I could not solve either. Does anyone have a clue ?