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• FFMpeg Out of sync audio/video in iOS application

  28 juillet 2016, par yogbd

  The app saves the camera output into a mov. file, then turn it to flv format that sent by AVPacket to rtmp server.
  It switch every time between two files, one is written by the camera output and the other one is sent.
  My problem is that the audio/video is getting out of sync after a while.

  The first buffer sent is allways 100% sync but after awhile it get messed.
  I belive its a DTS-PTS problem..

   if(isVideo)
  
  {
  
      packet->stream_index = VIDEO_STREAM;
  
     packet->dts = packet->pts = videoPosition;
  
      videoPosition += packet->duration = FLV_TIMEBASE * packet->duration * videoCodec->ticks_per_frame * videoCodec->time_base.num / videoCodec->time_base.den;
  
  
  
  }
  
  else
  
  {
  
      packet->stream_index = AUDIO_STREAM;
  
      packet->dts = packet->pts = audioPosition;
  
      audioPosition += packet->duration = FLV_TIMEBASE * packet->duration / audioRate;
  
  
  
     //NSLog(@"audio position = %lld", audioPosition);
  
  }
  
  
  
  packet->pos = -1;
  
  packet->convergence_duration = AV_NOPTS_VALUE;
  
  
  
  // This sometimes fails without being a critical error, so no exception is raised
  
  if((code = av_interleaved_write_frame(file, packet)))
  
  {
  
      NSLog(@"Streamer::Couldn't write frame");
  
  }
  
  av_free_packet(packet);

• FFMpeg php thumbnail generation fails with no error

  18 janvier 2017, par Carles Estevadeordal

  I have a thumbnail generation script that does not generate thumbnails, yet no error is reported, everything seems to be in order and it has even generated some thumbnails. Logging reveals that the objects are created correctly, the only part that seems to fail is the $frame->save part. If someone an give me any clue...

                  $frame_tmp_path='/tmp/app/frames/';
  
                  $frame_filename=$frame_tmp_path.$uuid.'_'.$offset.'_'.$type;
  
                  if(!file_exists ( $frame_filename )){
  
                      require_once $_SERVER['DOCUMENT_ROOT'] .'vendor/autoload.php';
  
  
  
                      $video_filename='http://website.com/memes/media/'.$uuid.'_'.$offset.'_normal';
  
                      //try {
  
                          $ffprobe = FFMpeg\FFProbe::create();
  
                          $video_duration=$ffprobe->format($video_filename) // extracts file informations
  
                                  ->get('duration');
  
                          $ffmpeg = FFMpeg\FFMpeg::create();
  
                          $video = $ffmpeg->open($video_filename);
  
                          error_log("File video duration: ".$video_duration);
  
                          if(!file_exists($frame_tmp_path)){
  
                              mkdir($frame_tmp_path, 0666, true);
  
                          }
  
                          $frame=$video->frame(FFMpeg\Coordinate\TimeCode::fromSeconds($video_duration*0.5),true);
  
                          error_log("frame timecode: ".$frame->getTimeCode().", filename: ".$frame_filename);
  
                          $frame->save($frame_filename);
  
                      //} catch (Exception $e) {
  
                      //    echo 'Excepción capturada: ',  $e->getMessage(), "\n";
  
                      //}
  
                  }
  
                  $meme_data=file_get_contents($frame_filename);

• FFMPEG Screen Flashing Green

  18 novembre 2022, par Devin Dixon

  I have this problem where my ffmpeg videos are flicking green. Example of the video is here :
https://www.glitch.fun/streams/31fea7e0-7523-4365-9780-31deee9e472c/watchrecording/efb841c0-4b87-4482-b165-990880a66f63

  


  My ffmpeg command is this :

  


  /usr/bin/ffmpeg -vaapi_device /dev/dri/renderD128 -y -v info -f x11grab -draw_mouse 0 -r 60 -s 1920x1080 -thread_queue_size 14000 -i :0.0+0,0 -f alsa -thread_queue_size 14000 -i plug:bsnoop -acodec aac -strict -2 -ar 44100 -b:a 128k -af aresample=async=1 -c:v h264_vaapi -vf format=nv12|vaapi,hwupload -preset medium -maxrate 14000k -bufsize 14000k -pix_fmt yuv420p -r 60 -crf 25 -g 120 -tune zerolatency -f flv rtmp://ingest.bingewave.com/live/[output_to_livestream] -pix_fmt yuv420p -r 60 -b:v 15000k -maxrate 15000k -bufsize 15000k -c:v h264_vaapi -vf format=nv12|vaapi,hwupload -preset medium -keyint_min 24 -level 3.0 -g 120 -tune zerolatency -f flv rtmp://127.0.0.1:1935/live/[output_to_recording]


  


  The reason why my fps and bitrate is so high and preset is so medium is because Glitch is an open source esports platform, and those kinds of settings are required for streaming of game graphics
The command has two outputs :

  


  

  • rtmp ://[output_to_livestream] goes to a livestream where users watch live

  


  • rtmp ://127.0.0.1:1935/live/[output to recording] goes a goes to a file

  


  


  And the output to the recording is captured by nginx and saved to a file as such :

  


  rtmp {
    server {
        listen 1935;
        chunk_size 4096;

        application live {
            live on;
            #Set this to "record off" if you don't want to save a copy of your broadcasts
            record all;
            # The directory in which the recordings will be stored.
            record_path /var/www/html/recordings;
            record_unique on;
            record_suffix -%d-%b-%y-%T.flv;
            on_record_done http://127.0.0.1:3000/recorded;
            # Turn on HLS
            exec /usr/bin/ffmpeg -vaapi_device /dev/dri/renderD128 -i rtmp://127.0.0.1:1935/live/$name -c:v copy -c:a copy -f flv rtmp://127.0.0.1/show/$name;
        }

        application show {
            live on;
            # Turn on HLS
            hls on;
            hls_path /mnt/hls/;
            hls_fragment 3;
            hls_playlist_length 60;
            # disable consuming the stream from nginx as rtmp
            deny play all;
        }
    }
}


  


  So the part that goes to the live is fine, no green flickering at all. But the part that goes to the recording is one that goes the above issue :

  


  -pix_fmt yuv420p -r 60 -b:v 15000k -maxrate 15000k -bufsize 15000k -c:v h264_vaapi -vf format=nv12|vaapi,hwupload -preset medium -keyint_min 24 -level 3.0 -g 120 -tune zerolatency -f flv rtmp://127.0.0.1:1935/live/[output_to_recording]


  


  I
s there something I need to be changing here ?