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• FFMpeg crashes on decoding MJpeg

  22 octobre 2012, par Lior Ohana

  I'm working with FFMpeg for decoding Mjpeg streams.
  Recently I've bumped into access violation exceptions from FFMpeg, after investigating, I found that due to network packet drops, I'm passing to the FFMpeg a frame that might have "gaps" in it.
  The FFMpeg probably crash since it jumps to a marker payload which doesn't exist in the frame's memory.

  Any idea where I can find a mjpeg structure validator ?
  Is there any way to configure FFMpeg to perform such validations by itself ?

  Thanks.

• Can MPMoviePlayerController play m3u8 file

  26 novembre 2013, par Nitesh

  I am trying to play a m3u8 file using MPMovieplayercontroller
  i pass the url to the MPMovieplayercontroller
  But it will not play. Is it possible ?

  I am converting flv,avi video file formats into m3u8 files using ffmpeg for live http streaming on my server.

  The m3u8 url works when i pass it to VLC as a network stream on my mac.
  I know this has been asked a number of times but i have not got any satisfactory answers.

  Regards
  Nitesh

• Optimizing FFmpeg/x264 Configuration for Ultra-Low Latency UDP Streaming [closed]

  17 décembre 2024, par pourjour

  I'm implementing a real-time screen streaming application using FFmpeg's libraries (libavcodec, libavformat) with H.264 encoding and UDP transport. While I have basic low-latency settings in place, I'm looking to minimize latency as much as possible while maintaining reasonable quality.
Here's my current encoder configuration :

  


  // Configure codec for low latency
codecContext->width = WIDTH;
codecContext->height = HEIGHT;
codecContext->time_base = AVRational{1, FPS};
codecContext->framerate = AVRational{FPS, 1};
codecContext->pix_fmt = AV_PIX_FMT_YUV420P;
codecContext->gop_size = 10;
codecContext->max_b_frames = 0;
codecContext->refs = 1;
codecContext->flags |= AV_CODEC_FLAG_LOW_DELAY;
codecContext->bit_rate = 3000000;

// x264 specific settings
av_opt_set(codecContext->priv_data, "preset", "ultrafast", 0);
av_opt_set(codecContext->priv_data, "tune", "zerolatency", 0);
av_opt_set(codecContext->priv_data, "delay", "0", 0);
av_opt_set(codecContext->priv_data, "profile", "baseline", 0);
av_opt_set(codecContext->priv_data, "x264opts",
           "no-mbtree:sliced-threads:sync-lookahead=0:rc-lookahead=0:"
           "no-scenecut:no-cabac:force-cfr", 0);


  


  For network transport, I'm using MPEGTS over UDP :

  


  QString url = QString("udp://%1:%2?pkt_size=1316").arg(targetAddress).arg(targetPort);


  


  Current issues :

  


  

  • Still experiencing 200-300ms latency Some quality degradation with
fast motion Occasional frame drops

  


  


  Questions :

  


  

  • Are there additional x264 options or FFmpeg settings I should
consider for reducing latency ?

  


  • What are the optimal GOP and bitrate
settings for balancing latency vs quality ?

  


  • Are there better muxer settings or alternative container formats I should consider ?

  


  • How can I optimize the network transport settings (packet size, buffering,
etc.) ?

  


  • Are there any tradeoffs I should be aware of with my current
configuration ?