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• FATE : use a less ambiguous end time for filter-trim-time test

  5 mai 2013, par Anton Khirnov

  FATE : use a less ambiguous end time for filter-trim-time test
  0.1 seconds at 25 fps is exactly 2.5 frames, which may be rounded either
  
  to 2 or 3 on different platforms.
  

  • [DBH] tests/fate/filter-video.mak

• Youtube livestream stops receiving video from time to time (ffmpeg)

  15 décembre 2020, par wht_5005

  I have ip cam, raspberry pi (Ubuntu 18.04.4 LTS (GNU/Linux 5.3.0-1036-raspi2 armv7l)) with ffmpeg (3.4.8-0ubuntu0.2) on board and I am trying to do 24/7 youtube livestream.
I have set up a service that start ffmpeg on boot. It receives rtsp stream from camera and sends it to youtube. Here is the ffmpeg setup :

  


  ffmpeg -thread_queue_size 512 -rtsp_transport tcp -i rtsp://cam_address -c:v copy -af "aresample=async=1:first_pts=0" -c:a aac -ac 2 -ar 44100 -fflags +genpts -f flv rtmp://youtube_address -nostdin -nostats


  


  I have noticed that ffmpeg may accidentally stop working from time to time (rather rarely but still) so the service should restart if ffmpeg crashes. Additionally just in case I have set up a cron job that restarts the service every hour, so if it stops working for some reason and that magic that should bring it up fails it should still get up within an hour.

  


  What bothers me, sometimes it stops working but in an unusual way. The service on raspberry pi is running, ffmpeg is running as well, nethogs shows that ffmpeg is both receiving and sending proper amount of data. Stream status on youtube is all right as if everything was just fine but there is no video there (it looks as if it was still loading/buffering but it is not). Restarting the service does not make it work. However if I stop the service, wait a few seconds and start it again the youtube stream starts working as it is supposed to.

  


  Why such things happen and how can I fix it ?

  


• Clip a video segment based on start time and end time in PyAv

  4 décembre 2018, par StackOverflowVeryHelpful

  I am using this library ( PyAV ) to convert an m3u8 stream to mkv stream.

  Is there a way to clip a video segment using PyAv. Example if say the video is of length 120 seconds and i want to clip the video from 20 second to 60 second

  Sample FFMPEG command would look something like this

  FFMPEG Command to Clip Video

  Here is my code to do the conversion from m3u8 to mkv

  import av
  
  
  
  input_ = av.open('input.m3u8')
  
  output = av.open('output.mkv', 'w')
  
  
  
  # setup from one to the other.
  
  in_stream = input_.streams.video[0]
  
  out_stream = output.add_stream(template=in_stream)
  
  
  
  for packet in input_.demux(in_stream):
  
  
  
      print(packet)
  
  
  
      # We need to skip the "flushing" packets that `demux` generates.
  
      if packet.dts is None:
  
          continue
  
  
  
      # We need to assign the packet to the new stream.
  
      packet.stream = out_stream
  
  
  
      output.mux(packet)
  
  
  
  output.close()