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• 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()

• c# what is the best way to record live frames as Video

  13 février 2015, par Balu

  I have been checking around to convert live frames into video. And I found (NReco.VideoConverter) ffmpeg lib to convert live frames to Video, but the problem is it is taking time to write each frame to ConvertLiveMediaTask (async live media task conversion).

  I have an event that provides (raw) frames (1920x1080) (25fps) from IpCamera. Whenever I get frame I am doing the following

  //Image availbale event fired
  
  //...
  
  
  
  //...
  
  // Record video is true
  
  if(record)
  
  {
  
  //////////////############# Time taking part ##############//////////////////////
  
  var bd = frameBmp.LockBits(new Rectangle(0, 0, frameBmp.Width, frameBmp.Height), ImageLockMode.ReadOnly, PixelFormat.Format24bppRgb);                        
  
    var buf = new byte[bd.Stride * frameBmp.Height];                       
  
    Marshal.Copy(bd.Scan0, buf, 0, buf.Length);
  
    // write to ConvertLiveMediaTask
  
    convertLiveMediaTask.Write(buf, 0, buf.Length); // ffMpegTask
  
    frameBmp.UnlockBits(bd);
  
  //////////////////////////////////////////////////////////////////////////////////
  
  }

  As the above part is taking much time, I am loosing the frames.

  //Stop recording
  
  convertLiveMediaTask.Stop(); //ffMpegTask

  Stop recording, for this part I have used BackgroundWorker, because this takes too smuch time to save the media to file.
  My question is how can I write the frame to ConvertLiveMediaTask in faster way ? are there any possibilites to write it in background ?
  Please give me suggestions.

• vsrc_movie : do not free avoption variables in uninit()

  20 juin 2013, par Anton Khirnov

  vsrc_movie : do not free avoption variables in uninit()
  The generic code frees them as well. Since av_free was used to free them
  
  instead of av_freep, this would result in a double free.
  

  • [DH] libavfilter/vsrc_movie.c