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• Streaming webm with ffmpeg/ffserver

  20 octobre 2014, par Mediocre Gopher

  I’m attempting to cast my desktop screen to an ffserver and stream it as a webm. I’m using the following ffserver configuration :

  <feed>               # This is the input feed where FFmpeg will send
  
     File ./feed1.ffm            # video stream.
  
     FileMaxSize 1G              # Maximum file size for buffering video
  
     ACL allow 127.0.0.1
  
     ACL allow localhost
  
  </feed>
  
  
  
  <stream>              # Output stream URL definition
  
     Feed feed1.ffm              # Feed from which to receive video
  
     Format webm
  
  
  
     # Audio settings
  
     AudioCodec vorbis
  
     AudioBitRate 64             # Audio bitrate
  
  
  
     # Video settings
  
     VideoCodec libvpx
  
     VideoSize 720x576           # Video resolution
  
     VideoFrameRate 25           # Video FPS
  
  
  
     AVOptionVideo cpu-used 10
  
     AVOptionVideo qmin 10
  
     AVOptionVideo qmax 42
  
     AVOptionVideo quality good
  
     AVOptionAudio flags +global_header
  
     PreRoll 15
  
     StartSendOnKey
  
     VideoBitRate 400            # Video bitrate
  
  </stream>

  And the following command on my desktop :

  ffmpeg -f x11grab -r 25 -s 1280x800 -i :0.0 -f alsa -i pulse http://127.0.0.1:8090/feed1.ffm

  With ffmpeg being version 2.4.2 and with libvpx enabled (latest on Arch). I get the error :

  [libvpx @ 0x20a21a0] CQ level 0 must be between minimum and maximum quantizer value (10-42)

  On the client side. As far as I can tell from calling ffmpeg -h full there’s no way of setting the cq-level, and setting qmin to 0 doesn’t work (it ends up as 3 for some reason, I guess ffmpeg enforces a minimum).

  This configuration seems to have worked for others on the internet, but I can’t see how if cq-level defaults 0. If anyone has any ideas I’d really appreciate it.

• avfilter/blend_modes : Always preserve constness

  7 septembre 2023, par Andreas Rheinhardt

  avfilter/blend_modes : Always preserve constness
  These casts cast const away temporarily ; they are safe, because
  
  the pointers that are initialized point to const data. But this
  
  is nevertheless not nice and leads to warnings when using
  
   Wcast-qual. blend_modes.c generates 546 (2*39*7) such warnings
  
  which is the majority of such warnings for FFmpeg as a whole.
  
  vf_blend.c and vf_blend_init.h also use this pattern ;
  
  they have also been changed.
  Reviewed-by : Paul B Mahol <onemda@gmail.com>
  
  Signed-off-by : Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
  

  • [DH] libavfilter/blend_modes.c
  • [DH] libavfilter/vf_blend.c
  • [DH] libavfilter/vf_blend_init.h

• Create conversion queue using ffmpeg and C #

  22 octobre 2017, par Alexei Agüero Alba

  Ok, the idea is to create a file queue that can be modified and reorganized (this is done) and for each file execute a ffmpeg process to convert it to another format.

  For conversion use Xabe.FFmpeg and .Net 4.5 all using async and await.

  The question would be how to execute an x ​​number of processes in parallel (example 4) of that variable queue and when one of them finishes executing the next one, keeping in execution always the same amount in parallel. I can start from scratch but I need ideas on how to do this in the simplest way possible. The program itself is simple (with gui) takes a folder and its subfolders all the video files and queues them and starts the conversion, you can add other folders with more files, and independent files reorder them, to convert whichever is the greater.

  At one point I found a package I think nuget (or github) that did exactly what I needed but I have not been able to get back.

  Thanks for your help in advance.

  Excuse the English because I use the translator of Google for being faster because my domain of this is limited but sufficient to understand the answers.

  ---

  Ok, I found what I was looking for called ProcessManager is a nupkg package. It has 2 years of development but seems stable. The only drawback is that it does not allow me to organize the conversion queue once you have added the files, although I have to try some ideas that maybe functions.

  var manager = new Manager(4); // Max 4 processes will be started simultaneously
  
  manager.Start();
  
  
  
  manager.ProcessErrorDataReceived += (sender, e) => Console.WriteLine(e.Data);
  
  manager.ProcessOutputDataReceived += (sender, e) => Console.WriteLine(e.Data);
  
  
  
  foreach (var videoFileName in Directory.EnumerateFiles("videos"))
  
  {
  
      var info = new ProcessInfo(
  
          "ffprobe.exe",
  
          string.Format("-v quiet -print_format json -show_format -show_streams \"{0}\"", videoFileName));
  
  
  
      manager.Queue(info);
  
  }

  Process Manager