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• latency when streaming x264

  18 novembre 2013, par tobsen

  I would like to produce a zerolatency live video stream and play it in VLC player with as little latency as possible.

  This are the settings I currently use :

  x264_param_default_preset( &m_Params, "veryfast", "zerolatency" );
  
  
  
  m_Params.i_threads              =   2;
  
  m_Params.b_sliced_threads       =   true;
  
  m_Params.i_width                =   m_SourceWidth;
  
  m_Params.i_height               =   m_SourceHeight;
  
  
  
  m_Params.b_intra_refresh        =   1;
  
  
  
  m_Params.b_vfr_input            =   true;
  
  m_Params.i_timebase_num         =   1;
  
  m_Params.i_timebase_den         =   1000;
  
  
  
  m_Params.i_fps_num              =   1;
  
  m_Params.i_fps_den              =   60;
  
  
  
  m_Params.rc.i_vbv_max_bitrate   =   512;
  
  m_Params.rc.i_vbv_buffer_size   =   256;
  
  m_Params.rc.f_vbv_buffer_init   =   1.1f;
  
  
  
  m_Params.rc.i_rc_method         =   X264_RC_CRF;
  
  m_Params.rc.f_rf_constant       =   24;
  
  m_Params.rc.f_rf_constant_max   =   35;
  
  
  
  m_Params.b_annexb               =   0;
  
  m_Params.b_repeat_headers       =   0;
  
  m_Params.b_aud                  =   0;
  
  
  
  x264_param_apply_profile( &m_Params, "high" );

  Using those settings, I have the following issues :

  • VLC shows lots of missing frames (see screenshot, "verloren"). I am not sure if this is an issue.
  • If I set a value <200ms for the network stream delay in VLC, VLC renders a few frames and than stops to decode/render frames.
  • If I set a value >= 200ms for the network stream delay in VLC, everything looks good so far but the latency is, obviously, 200ms, which is too high.

  Question :
  Which settings (x264lib and VLC) should I use in order to encode and stream with as little latency as possible ?

  

• ffmpeg : create a video from images and sounds

  27 septembre 2018, par Yuri Gusak

  You need to create a video from a set of pictures and sounds using ffmpeg.
  Set of pictures : frame_% d.jpg
  Sounds :
  sound1.mp3 (from 0 ms)
  sound2.mp3 (from 1000 ms)
  sound3.mp3 (from 2000 ms)
  

  I can create a video with one sound :

  -i frame_% d.jpg -i sound1.mp3 -r 30 -s 1280x720 -preset ultrafast -crf 25 -shortest movie.mp4

  and it works.

  But I need to add some sounds at different times. How can I do that ? May be -filter_complex will help ?

• C# capture specific frame from video file using ffmpeg takes too long

  6 septembre 2018, par Ditza

  I am trying to take specific frame from full HD video file. I am using Accord.Video.FFMPEG.
  The read ReadVideoFrame takes something like 200ms. I need It to be much faster.
  Am I doing something wrong or this is the time it should takes ? What should I use to get the frame in few milliseconds ?

  VideoFileReader reader = new VideoFileReader();
  
  reader.Open(source);
  
  int frameN = (int)Math.Floor(((reader.FrameRate).ToDouble() * pos.Milliseconds) / 1000);
  
  Bitmap bkg = reader.ReadVideoFrame(frameN);

  Thanks,
  Ditza