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• pgssubdec : reset rle_data_len/rle_remaining_len on allocation error

  31 janvier 2017, par Andreas Cadhalpun

  pgssubdec : reset rle_data_len/rle_remaining_len on allocation error
  The code relies on their validity and otherwise can try to access a NULL
  
  object->rle pointer, causing segmentation faults.
  Signed-off-by : Andreas Cadhalpun <Andreas.Cadhalpun@googlemail.com>
  
  Signed-off-by : Diego Biurrun <diego@biurrun.de>
  

  • [DBH] libavcodec/pgssubdec.c

• avcodec/nvdec : reset bitstream_len/nb_slices when resetting bitstream pointer

  29 mars 2024, par Timo Rothenpieler

  avcodec/nvdec : reset bitstream_len/nb_slices when resetting bitstream pointer
  

  • [DH] libavcodec/nvdec.c

• FFmpeg massive data loss when writing large data and swapping segments

  25 avril 2023, par Bohdan Petrenko

  I have an ffmpeg process running which continiously writes audio data to two 30 seconds (for testing, I'm actually planning to use 5 minutes) segments. The problem is that when I write some audio data with length more than size of two segments (60 seconds), 8-17 seconds of audio is lost. Here is how I run FFmpeg and write data :

  


      _ffmpeg = Process.Start(new ProcessStartInfo
    {
        FileName = "ffmpeg",
        Arguments = 
            $"-y -f s16le -ar 48000 -ac {Channels} -i pipe:0 -c:a libmp3lame -f segment -segment_time {BufferDuration} -segment_format mp3 -segment_wrap 2 -reset_timestamps 1 -segment_list \"{_segmentListPath}\" \"{segmentName}\"",
        UseShellExecute = false,
        RedirectStandardInput = true
    })!;
    // Channels is usually 1, BufferDuration is 30


  


  And here is how I write data :

  


  public async Task WriteSilenceAsync(int amount)
{
    if (amount > _size) amount = _size; // _size is 48000 * 1 * 2 * 30 * 2 = 5760000 (size of 1 minute of audio)
    
    var silence = _silenceBuffer.AsMemory(0, amount);
    await _ffmpeg.StandardInput.BaseStream.WriteAsync(silence);
}


  


  I tried to change the ffmpeg parameters and ways I write data. But I haven't found the solution.

  


  I'm sure that the problem is caused by ffmpeg segments, because if I disable segmenting and write audio to a single file, there are no problems with data loss or audio missmatch. I also sure that amount of silence to add in WriteSilenceAsync() method is calculated right. I'm not sure if the problem appears with data length more than 30 seconds but less then 1 minute, but I think it doesn't.

  


  I don't know how to solve this problem and would be glad to see any suggestions or solutions.