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• Convert AVFrame to CVPixelBufferRef to use in function CVOpenGLESTextureCacheCreateTextureFromImage

  7 juin 2013, par hard gamer

  I've a custom video player on iOS platform, I read many threads for performance tuning about using CVOpenGLESTextureCacheCreateTextureFromImage API. But, this API is always used with Apple decoders, so as Apple decoders provide CVPixelBufferRef, I can not find any way to convert ffmpeg's AVFrame to CVPixelBufferRef...

  Can anyone guide me for this topic ?

  Is it possible to use CVOpenGLESTextureCacheCreateTextureFromImage API for AVFrames of ffmpeg ? If yes, how ?

• FFMPEG “buffer queue overflow, dropping.” while filter_complex concating

  8 août 2019, par March3April4

  I’m using the below command to concat several videos to a single video.

  ffmpeg -i /storage/emulated/0/Cache/1565235095822.mp4
  
  -i /storage/emulated/0/Cache/1565235097989.mp4
  
  -i /storage/emulated/0/Cache/1565235099167.mp4 
  
  -i /storage/emulated/0/Cache/1565235100276.mp4
  
  -i /storage/emulated/0/Cache/1565235096982.mp4
  
  -filter_complex [0:v:0] [0:a:0] [1:v:0] [1:a:0] [2:v:0] [2:a:0] [3:v:0] [3:a:0] [4:v:0] [4:a:0] concat=n=5:v=1:a=1 [v] [a]
  
  -map [v]
  
  -map [a]
  
  -max_muxing_queue_size 9999
  
  -preset ultrafast
  
  /storage/emulated/0/Cache/1565235101418.mp4

  The input videos are also made by ffmpeg, and are about 1 megabyte big. (Each consists of a single picture and an audio)

  The above command line works well for mainstream devices such as galaxy s10 series, but for models like Lg K10, the below line appears.

  [Parsed_concat_0 @ 0xb9ab05a0] Buffer queue overflow, dropping.

  The encoding does not stop even though the above line shows up, but the result video contains some time skips and missing audio.

  I assumed that this has to do with performance of the device itself, so, I tried to do the job without encoding. I’ve tried the concat demuxer with no luck.

  What else can I try to make this to work ? Any help will be thankful.

  ------------------Edit-------------------------

  The ffmpeg videos are create by the following command.

          String[] array = {
  
                   "-framerate", "1",
  
                  "-i", "targetVideo.png",
  
                  "-i", "targetAudio.mp3",
  
                  "-r", "14",
  
                  "-c:v", "libx264",
  
                  "-c:a", "aac",
  
                  "-pix_fmt", "yuv420p",
  
                  "-video_track_timescale", "90000",
  
                  "-c:a", "copy",
  
                  outputPath.mp4};

• Show motion compensated images in ffmpeg

  29 novembre 2017, par igon

  This guide shows how to visualize with FFmpeg interesting features (quantization parameters, motion vectors, ...) of an encoded video. One things that I find missing is a way to show motion compensated frames and/or residual frames.

  Is this information exposed by encoders ? Is there a way to visualize it ?