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• swscale : make handle_formats() safe to be called multiple times

  14 juillet 2013, par Michael Niedermayer

  swscale : make handle_formats() safe to be called multiple times
  Signed-off-by : Michael Niedermayer <michaelni@gmx.at>
  

  • [DH] libswscale/utils.c

• Why my log printed many times using c api of ffmpeg decoder v2.8 which should be printed once when the callback return value is 1

  30 juillet 2019, par user10960024

  Documentation said when the callback functor interrupt_cb return 1, the blocking operation will be aborted. However, my program echo the log many times which should be printed only once log before it quit. How can I fix it ?

  AVFormatContext* formatContext = libffmpeg::avformat_alloc_context();
  
  formatContext->interrupt_callback.callback = interrupt_cb;
  
  formatContext->interrupt_callback.opaque = formatContext;
  
  
  
  int interrupt_cb(void *ctx)
  
  {
  
      if (...)
  
      {
  
          LOG(WARNING) << "decoder timeout!"; // it print many times
  
          return 1;
  
      }
  
      return 0;
  
  }

  I expect the output would be printed only once.

• combine video and audio .webm files based on wallclock times

  30 juillet 2021, par Zach

  I have a node server recording webrtc streams as separate video/audio files via ffmpeg.
I'm running ffmpeg via node's

  


  child_process.spawn('ffmpeg', commandArgs);


  


  Unfortunately, when I try to combine video and audio files later on, I don't know when ffmpeg created the first frame of each file, resulting in out of sync faces and voices :(

  


  Here's my command line args for piping the stream into ffmpeg

  


   '-loglevel',
  'debug',
  '-reorder_queue_size',
  '0',
  '-protocol_whitelist',
  'pipe,udp,rtp',
  '-fflags',
  '+genpts',
  '-f',
  'sdp',
  '-i',
  'pipe:0',
  '-map',
  '0:v:0',
  '-c:v',
  'copy',
  '-use_wallclock_as_timestamps',
  '1',
  '-timestamps',
  'mono2abs',
  '-flags',
  '+global_header',
  './recordings/video_1627600996166.webm'


  


  I was thinking that it might be possible to set the timestamps of packets to the linux's clock times, and tried a bunch of flags (-timestamps abs, -timestamps mono2abs, -use_wallclock_as_timestamps 1) but nothing seemed to change the result in the file. (I also have tried moving the time commands all around).

  


  packet|codec_type=video|stream_index=0|pts=0|pts_time=0.000000|dts=0|dts_time=0.000000|duration=N/A|duration_time=N/A|convergence_duration=N/A|convergence_duration_time=N/A|size=14568|pos=552|flags=K_


  


  Time always starts at 0.

  


  Any help figuring out how to get accurate times from my recorded audio/video .webm files so I can accurately combine them would be amazing.

  


  Thanks so much :)