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• C# capture specific frame from video file using ffmpeg takes too long

  6 septembre 2018, par Ditza

  I am trying to take specific frame from full HD video file. I am using Accord.Video.FFMPEG.
  The read ReadVideoFrame takes something like 200ms. I need It to be much faster.
  Am I doing something wrong or this is the time it should takes ? What should I use to get the frame in few milliseconds ?

  VideoFileReader reader = new VideoFileReader();
  
  reader.Open(source);
  
  int frameN = (int)Math.Floor(((reader.FrameRate).ToDouble() * pos.Milliseconds) / 1000);
  
  Bitmap bkg = reader.ReadVideoFrame(frameN);

  Thanks,
  Ditza

• FFMpeg generated m3u8 segmented videos long delay before playback starts [migrated]

  21 novembre 2014, par Michael Gaylord

  I am using ffmpeg to generate a segmented list of files in order to stream them to an iOS app. The list of files is generated fine but when it comes time to play them, the video needs to be downloaded in its entirety before playback starts. This behaviour seems to be the case on iOS, Safari and VLC.

  Does anybody know why this is happening and how I can improve the performance of playback ? I have complete control over how the files are recorded in iOS, as well as how they are processed. Here is a sample stream :

  http://www.bytesizecreations.com/storie-test/hls.m3u8

  Here are my ffmpeg commands to generate the segments from the file :

  ffmpeg -i joined.ts -flags -global_header -vcodec copy -acodec copy -map 0 -f segment -segment_time 2 -segment_list hls.m3u8 -segment_list_size 999999 -segment_format mpegts out%03d.ts

  Here is the output of ffprobe on the file :

    libavutil      54.  7.100 / 54.  7.100
  
    libavcodec     56.  1.100 / 56.  1.100
  
    libavformat    56.  4.101 / 56.  4.101
  
    libavdevice    56.  0.100 / 56.  0.100
  
    libavfilter     5.  1.100 /  5.  1.100
  
    libavresample   2.  1.  0 /  2.  1.  0
  
    libswscale      3.  0.100 /  3.  0.100
  
    libswresample   1.  1.100 /  1.  1.100
  
    libpostproc    53.  0.100 / 53.  0.100
  
  Input #0, mpegts, from 'joined.ts':
  
    Duration: 00:00:07.96, start: 1.441667, bitrate: 3899 kb/s
  
    Program 1 
  
      Metadata:
  
        service_name    : Service01
  
        service_provider: FFmpeg
  
      Stream #0:0[0x100]: Video: h264 (High) ([27][0][0][0] / 0x001B), yuv420p, 1280x720, 24 fps, 24 tbr, 90k tbn, 180k tbc
  
      Stream #0:1[0x101](und): Audio: aac ([15][0][0][0] / 0x000F), 44100 Hz, stereo, fltp, 222 kb/s

• Why android ffmpeg takes so long time to resize mp4 video from high resolution ?

  1er septembre 2018, par Kasim Rangwala

  I’m resizing  30 sec long ( 59.98 MB) mp4 video with resolution of 1920 X 1080 to 1280 X 720 using following ffmpeg command in android.

  ["-i", inputVideo!!.path, "-vf", "scale=720:1280", outputVideo.path, "-hide_banner"]

  converted video output is very good ( 6.6MB). but, ffmpeg conversion take so much time. Is there any options available that I can reduce the conversion time ?

  update

  If output format is other than mp4. it is fine but, conversion time must be reduce.

  Thanks.