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• lavfi : add a libplacebo filter

  26 juillet 2021, par Niklas Haas

  lavfi : add a libplacebo filter
  This filter conceptually maps the libplacebo `pl_renderer` API into
  
  libavfilter, which is a high-level image rendering API designed to work
  
  with an RGB pipeline internally. As such, there's no way to avoid e.g.
  
  chroma interpolation with this filter, although new versions of
  
  libplacebo support outputting back to subsampled YCbCr after processing
  
  is done.
  That being said, `pl_renderer` supports automatic integration of the
  
  majority of libplacebo's shaders, ranging from debanding to tone
  
  mapping, and also supports loading custom mpv-style user shaders, making
  
  this API a natural candidate for getting a lot of functionality out of
  
  relatively little code.
  In the future, I may approach this problem either by rewriting this
  
  filter to also support a non-renderer codepath, or by upgrading
  
  libplacebo's renderer to support a full YCbCr pipeline.
  This unfortunately requires a very new version of libplacebo (unreleased
  
  at time of writing) for timeline semaphore support. But the amount of
  
  boilerplate needed to hack in backwards compatibility would have been
  
  very unreasonable.
  

  • [DH] configure
  • [DH] libavfilter/Makefile
  • [DH] libavfilter/allfilters.c
  • [DH] libavfilter/vf_libplacebo.c

• FFMPEG Process not ending when encoding libx264

  17 janvier 2015, par Jamie Hartnoll

  Well, I’m very new and inexperienced with using Process and using FFMPEG, and command line processes in ASP.NET in general... but, have something working, nearly !

  I’m trying to convert AVI files to MP4 files which can be streamed to an HTML5 player.

  After a lot of messing around, I have found that for this to work it has to be encoded with X264, but, for some reason, when I do this the FFMPEG process does not close/end.

  The code I am using is below and works perfectly if I use -vcodec mpeg4, but when I use -vcodec libx264, whilst it works and produces the file I need to Process never ends.

  To get round this, I am temporarily adding 5 second time out to WaitForExit in the Process, but this is definitely a hack and whilst is OK with what I am doing at the moment is not a robust solution.

  Can anyone point me in the direction of why this is happening ?!

  Public Shared Sub AviToMP4(VideoFileName As String, Optional DeleteSource As Boolean = True)
  
  
  
      Dim SourceFile As String = VideoFileName.Replace(".avi", "")
  
      Dim DestinationFile As String = SourceFile
  
  
  
      Dim FFMPEG_EXE_PATH As String = """" & System.AppDomain.CurrentDomain.BaseDirectory() & "ffMPEG.exe"""
  
      Dim Codec = "libx264" ' libx264 || mpeg4
  
      Dim cdml = " -i """ & SourceFile & ".avi"" -acodec aac -strict -2 -b:a 128k -vcodec " & Codec & " -b:v 1200k -flags +aic+mv4 """ & DestinationFile & ".mp4"""
  
  
  
      Dim ProcessorLocation As String = FFMPEG_EXE_PATH
  
      Dim CommandLines As String = cdml
  
  
  
      Try
  
          Dim ProcessingResponse As String = ""
  
          Using myProcess As New Process()
  
              myProcess.StartInfo.UseShellExecute = False
  
              myProcess.StartInfo.RedirectStandardInput = True
  
              myProcess.StartInfo.RedirectStandardOutput = True
  
              myProcess.StartInfo.RedirectStandardError = True
  
              myProcess.StartInfo.CreateNoWindow = True
  
              myProcess.StartInfo.WindowStyle = ProcessWindowStyle.Hidden
  
              myProcess.StartInfo.FileName = ProcessorLocation
  
              myProcess.StartInfo.Arguments = CommandLines
  
              myProcess.Start()
  
              ProcessingResponse = myProcess.StandardError.ReadToEnd()
  
              myProcess.WaitForExit(5000) ' <<< Have to put a timeout here for libx264 or it will never end!!
  
          End Using
  
          HttpContext.Current.Response.Write("<pre>" &amp; ProcessingResponse &amp; "</pre><hr />")
  
          If File.Exists(SourceFile) AndAlso DeleteSource Then
  
              File.Delete(SourceFile)
  
          End If
  
      Catch ex As Exception
  
          HttpContext.Current.Response.Write(ex.ToString &amp; "<p>")
  
      End Try
  
  
  
  End Sub
  
  </p>

• Use ffmpeg to segment streaming video

  4 décembre 2022, par Marc

  Suppose I have a streaming video URL rtsp ://whatever and I wish to store that video stream to my file system as a series of files off approximately the same size or duration. Ideally I would like to store the files with a start and stop timestamp as part of the filename, and each file should be such that it can stand on its own to be displayed as a video file if someone wants to view it. I understand that ffmpeg has a segment command option that allows me to segment by time and store in a series of files like outfile%3d.dat or whatever. But suppose I want to do this perpetually and cycle the files (age out old ones) when the total size of all the saved files exceeds a specific value. For example, suppose I want to save the most recent 500GB of video from this streaming URL and keep doing this day after day continuously into the distant future. What happens to the output filename after outfile999.dat is saved ? Does the count start over at 0 ? Or does ffmpeg just stop or crash ? Is there an ffmpeg command that can segment and age out old files, or is this something I would have to do running another program simultaneously or would I have to hack into ffmpeg itself to do this ? I'm pretty new to ffmpeg so any suggestions you ffmpeg experts might have on how to do this would be welcome. I also welcome suggestions for other command line Linux tools that might be better for this application.

  



  UPDATE : So it turns out that ffmpeg has a segmenter built in, and I can segment the files such that the filenames have the video start datetime as part of the filename. I used a command like this :

  



  ffmpeg -i rtsp://camera_feed_url_here -c copy -f segment -segment_list out.list -segment_time 900 \ -segment_atclocktime 1 -strftime 1 "%Y-%m-%d_%H-%M-%S.mkv"


  



  That's the good news. The bad news is that when I run this command, after about 1 minute it just throws this error and stops :

  



  rtsp ://camera_feed_url_here : Invalid data found when processing input

  



  No other error or diagnostic mesages are printed out. Even when I run with -loglevel debug, it just seems to die with this error message.

  



  When I built ffmpeg, used this :

  



  ./configure --enable-demux='rtsp,rtp,sdp,flac,gif,image2,image2pipe,matrosk' --enable-network --enable-protocols --enable-decoder=h264


  



  Any ideas what I'm doing wrong and how I can make this error go away ?