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• How to process video stream ?

  27 avril 2016, par sharpener

  I would like to ask some experienced multimedia professional how to proceed with following task :

  Given URL provides video stream and we would like to get access to decoded frames (byte stream in memory) in managed Win7+ application (C#). We don’t want to render/present the frames the standard way. The video format is known but not fixed (might get changed between two successive sessions, but we will know the parameters).

  So far, I have found there are several methods and I have build following picture in my mind :

  1. ffmpeg wrapper
     • Pros
       1. Self contained (no dependency to windows technologies)
       2. Powerful
     • Cons
       1. Little more complex to understand
       2. Lot of different wrapping variants (FFmpeg.NET, ffmpeg-sharp, ffmpeg-shard, FFmpeg.AutoGen, ...)
  2. DirectShow wrapper
     • Pros
       1. Widely used/supported technology (variaous filters freely available)
       2. Nice/detailed documentation on MSDN
     • Cons
       1. Quite old
       2. Considered obsolete from the point of author’s view (available only for desktop model on runtime >= Win8)
  3. MediaFoundation wrapper
     • Pros
       1. Theoretical successor of DirectShow, so should be available in the future
     • Cons
       1. Seems to be not as good as DirectShow
       2. Not very popular, limited "community" support
  4. FFmpegInterop wrapper
     • Pros
       1. Microsoft’s open source wrapper alternative
     • Cons
       1. Not available for runtime < Win8

• lavf/async : Fix ring_write return value

  29 septembre 2022, par Guangyu Sun

  lavf/async : Fix ring_write return value
  This fixes a regression from commit 36117968ad.
  wrapped_url_read() used to be able to return positive number from
  
  ffurl_read(). It relies on the result to check if EOF is reached in
  
  async_buffer_task().
  But FIFO callbacks must return 0 on success. This should be handled
  
  in ring_write() instead.
  Test case :
  
    ffmpeg -f lavfi -i testsrc -t 1 test.mp4
  
    ffmpeg -i async:test.mp4
  Signed-off-by : Guangyu Sun <gsun@roblox.com>
  
  Signed-off-by : Anton Khirnov <anton@khirnov.net>
  

  • [DH] libavformat/async.c

• ffmpeg to encode MKV or MP4 with segmented Parts in one file

  28 juillet 2014, par Phil

  Is it Possible to create an MP4 or MKV file where the Video, Meta and Audio Data is segmented and placed alternated in a single File ? (By segmented I don’t mean different Video or Audio Tracks.)

  So that it looks like something like this :
  [meta][video][audio][meta][video][audio]…

  I searched for "segmenting", "clustering", and other buzz words. But the most searches ended up in an HTTP-Livestreaming where One File is segmented in single files.
  That Segmenting Technology is okay (so you can stream it). But I don’t want these segments in single Files, i want them to be in one single MKV or MP4 File.

  Maybe someone has any clue.