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• FFmpeg av_read_frame not reading frames properly ?

  16 juin 2019, par Sir DrinksCoffeeALot

  Alright, so I’ve downloaded some raw UHD sequences in .yuv format and encoded them with ffmpeg in .mp4 container (h264 4:4:4, 100% quality, 25fps). When i use ffprobe to find out how many frames are encoded i get 600, so that’s 24 secs of video.

  BUT, when i run those encoded video sequences through av_read_frame i only get like 40-50% of frames processed before av_read_frame returns error code -12. So I’m wild guessing that there are some data packages in middle of the streams which get read by av_read_frame and forces a function to return -12.

  What my questions are, how should i deal with this problem so i can encode full number of frames (600) ? When av_read_frame returns value different from 0 should i av_free_packet and proceed to read next frame ? Since av_read_frame returns values < 0 for error codes, which error code is used for EOF so i can insulate end of file code ?

• FFmpeg av_read_frame not reading frames properly ?

  2 août 2016, par Sir DrinksCoffeeALot

  Alright, so I’ve downloaded some raw UHD sequences in .yuv format and encoded them with ffmpeg in .mp4 container (h264 4:4:4, 100% quality, 25fps). When i use ffprobe to find out how many frames are encoded i get 600, so that’s 24 secs of video.

  BUT, when i run those encoded video sequences through av_read_frame i only get like 40-50% of frames processed before av_read_frame returns error code -12. So I’m wild guessing that there are some data packages in middle of the streams which get read by av_read_frame and forces a function to return -12.

  What my questions are, how should i deal with this problem so i can encode full number of frames (600) ? When av_read_frame returns value different from 0 should i av_free_packet and proceed to read next frame ? Since av_read_frame returns values < 0 for error codes, which error code is used for EOF so i can insulate end of file code ?

• 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