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• Cannot find installation of real FFmpeg (which comes with ffprobe)

  29 mars 2023, par Asm Goni

  I was trying to fit a generator into a model and I got this error : 
AssertionError: Cannot find installation of real FFmpeg (which comes with ffprobe).

  



  I have looked over many of the solutions on GitHub and other questions on Stack Overflow but none of them worked for me.

  



  Here is one of the commands I ran :

  



  sudo add-apt-repository ppa:mc3man/trusty-media  
sudo apt-get update  
sudo apt-get install ffmpeg  
sudo apt-get install frei0r-plugins  


  



  pip list also indicates the presence of ffmpeg-1.4

  



  In addition, I tried force reinstalling and updating ffmpeg just in case any dependencies were not installed properly.

  



  I also set the skvideo's path for ffmpeg manually :

  



  skvideo.setFFmpegPath('/usr/local/lib/python3.6/dist-packages/ffmpeg/')


  



  This returns : /usr/local/lib/python3.6/dist-packages/skvideo/__init__.py:306: UserWarning: ffmpeg/ffprobe not found in path: /usr/local/lib/python3.6/dist-packages/ffmpeg/
  warnings.warn("ffmpeg/ffprobe not found in path: " + str(path), UserWarning)

  



  By the way, when I try installing, it also returns this error, I don't know what to do about this :

  



  Get:127 http://archive.ubuntu.com/ubuntu bionic/main amd64 vdpau-driver-all amd64 1.1.1-3ubuntu1 [4,674 B]
Fetched 60.4 MB in 7s (8,769 kB/s)
E: Failed to fetch http://security.ubuntu.com/ubuntu/pool/main/w/wavpack/libwavpack1_5.1.0-2ubuntu1.1_amd64.deb  404  Not Found [IP: 91.189.88.149 80]
E: Unable to fetch some archives, maybe run apt-get update or try with --fix-missing?


  



  I ran apt-get update --fix-missing and that didn't make anything better.

  



  Is there a solution to this ?

  


• While transcoding to mpegts ffmpeg creates the first frame after 1.48 seconds delay

  15 mars 2018, par Biraj B Choudhury

  I have transcoded a file to mpegts using the following command

   ./ffmpeg -y -i big_buck_bunny_720p_5mb.mp4  -vcodec libx264  -x264opts "keyint=48:min-keyint=48:no_scenecut" -r 23.976 -c:a copy  -f mpegts test.mpegts

  When I run ffprobe on it -

  ./ffprobe  -i  test.mpegts  -select_streams v -show_frames -of csv

  I see that the first frame starts at 1.48 seconds why is this so ?

  Input #0, mpegts, from 'test.mpegts':
  
    Duration: 00:00:29.61, start: 1.483422, bitrate: 1964 kb/s
  
    Program 1 
  
      Metadata:
  
        service_name    : Service01
  
        service_provider: FFmpeg
  
      Stream #0:0[0x100]: Video: h264 (High) ([27][0][0][0] / 0x001B), yuv420p(progressive), 1280x720 [SAR 1:1 DAR 16:9], 23.98 fps, 23.98 tbr, 90k tbn, 47.95 tbc
  
      Stream #0:1[0x101](und): Audio: aac (LC) ([15][0][0][0] / 0x000F), 48000 Hz, 5.1, fltp, 406 kb/s
  
  frame,video,0,1,133508,1.483422,133508,1.483422,133508,1.483422,3753,0.041700,564,112008,1280,720,yuv420p,1:1,I,0,0,0,0,0
  
  frame,video,0,0,137262,1.525133,137262,1.525133,137262,1.525133,3753,0.041700,125584,1110,1280,720,yuv420p,1:1,B,2,0,0,0,0

  After some research I added "muxdelay 0" to my command

  ./ffmpeg -y -i big_buck_bunny_720p_5mb.mp4  -vcodec libx264  -x264opts "keyint=48:min-keyint=48:no_scenecut" -r 23.976 -c:a copy  -muxdelay 0 -f mpegts test.mpegts

  And now I get the following in ffprobe

  Input #0, mpegts, from 'test.mpegts':
  
    Duration: 00:00:29.61, start: 0.083422, bitrate: 1987 kb/s
  
    Program 1 
  
      Metadata:
  
        service_name    : Service01
  
        service_provider: FFmpeg
  
      Stream #0:0[0x100]: Video: h264 (High) ([27][0][0][0] / 0x001B), yuv420p(progressive), 1280x720 [SAR 1:1 DAR 16:9], 23.98 fps, 23.98 tbr, 90k tbn, 47.95 tbc
  
      Stream #0:1[0x101](und): Audio: aac (LC) ([15][0][0][0] / 0x000F), 48000 Hz, 5.1, fltp, 406 kb/s
  
  frame,video,0,1,7508,0.083422,7508,0.083422,7508,0.083422,3753,0.041700,564,112008,1280,720,yuv420p,1:1,I,0,0,0,0,0
  
  frame,video,0,0,11262,0.125133,11262,0.125133,11262,0.125133,3753,0.041700,125584,1110,1280,720,yuv420p,1:1,B,2,0,0,0,0

  Can anybody help me understand what is this muxdelay that is contributing to 1.4 seconds of delay and what is contributing to the remaining 0.08 seconds of delay.

  The first frame is at 0.000 when the output is mp4 so this is something particular to mpegts.

• rtpdec : fix issue with conversion from unsigned to signed

  20 février 2015, par Gilles Chanteperdrix

  rtpdec : fix issue with conversion from unsigned to signed
  When receiving an RTCP packet, the difference between the last RTCP
  
  timestamp and the base timestamp may be negative. As these timestamps
  
  are of the uint32_t type, the result becomes a large integer. Cast
  
  the difference to int32_t to avoid this issue.
  The result of this issue is very large start times for RTSP
  
  streams, and difficulty to restart correctly after a pause.
  Signed-off-by : Gilles Chanteperdrix <gilles.chanteperdrix@xenomai.org>
  
  Signed-off-by : Martin Storsjö <martin@martin.st>
  

  • [DBH] libavformat/rtpdec.c