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• Timing breaks concatenating two identical videos after one has ATEMP/SETPTS altered

  25 mai 2019, par user3144514

  Video (B)
  Copy pasted and then doubled speed with Setpts and Atempo as Video (A)

  Concatenating them results in a video with the (A) portion playing at the expected 2x speed, but the (B) portion playing back at 1/2 speed.

  I am simply trying to speed up sections of video that are repetative and merge them back in.

  I have tried doing another round of SETPTS/ATEMPO with 1.0 values, but it doesn’t alter the outcome.

  I have also tried forcibly re-encoding A and B to ensure they match in formats, still no change.

  Speed Change

  ffmpeg -i source.mp4 -filter_complex "[0:v]setpts=0.5*PTS[v];[0:a]atempo=2.0[a]" -map "[v]" -map "[a]" A.mp4

  Concatenation

  ffmpeg -i A.mp4 -c copy -bsf:v h264_mp4toannexb -f mpegts x1.ts
  
  ffmpeg -i B.mp4 -c copy -bsf:v h264_mp4toannexb -f mpegts x2.ts
  
  ffmpeg -i "concat:x1.ts|x2.ts" -c copy -bsf:a aac_adtstoasc C.mp4

  Do I need to use some other method to alter the playback rate without changing some internal timing value ?

  Or is there some way to fix the rates after adjusting SETPTS and ATEMPO so that the timing is restored ?

• FFMPEG av_read_frame() return an I/O error (-5) ?

  7 mars 2019, par vominhtien961476

  I’m using ffmpeg library to capture screen (desktop). Everything works fine when I run my app in debug/release mode. The I/O error comes when this app run in c# window service mode (win 10 OS). I googled but still don’t know why the error come. In the service mode there is no problem when connecting to some rtsp link (Camera) except desktop capture.

  AVInputFormat * pAVInputFormat = av_find_input_format("gdigrab"); 
  
  if (pAVInputFormat != NULL) 
  
  { 
  
     int err = avformat_open_input(&pFormatCtx, "desktop", pAVInputFormat, NULL); 
  
     if(err== 0) 
  
     { 
  
        err = av_read_frame(&pFormatCtx, &packet); 
  
        if (err < 0) 
  
        { 
  
            char errs[AV_ERROR_MAX_STRING_SIZE]; 
  
            av_make_error_string(errs, AV_ERROR_MAX_STRING_SIZE, err ); 
  
            String^ errStr = gcnew String(errs); 
  
            WriteLog("Error in function av_read_frame() return = " + errStr); 
  
            return -1; 
  
       } 
  
     } 
  
  }

  ---

• libavformat/mpegtsenc : allow to set service_type in sdt

  2 février 2015, par dhead666

  libavformat/mpegtsenc : allow to set service_type in sdt
  This adds an option to set the service type in mpegts as defined in ETSI 300 468.
  I added what I believe are the most useful service types as pre defined values,
  
  the others can be sent by using their hexdecimal form directly (e.g. -mpegts_service_type digital_radio, -mpegts_service_type 0x07).
  I’ve been using this patch in order to pipe internet radio stream (originally as HLS/m3u8) from ffmpeg to tvheadend,
  
  when the service type set right tvheadend recognize the mpegts stream as a radio channel.
  The patch in its original form was written by linuxstb from freenode’s hts channel which allowed me pushing it upstream.
  This close issue 4118.
  Signed-off-by : Michael Niedermayer <michaelni@gmx.at>
  

  • [DH] doc/muxers.texi
  • [DH] libavformat/mpegtsenc.c