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• ffmpeg split avi into frames with known frame rate

  31 mai 2016, par Myx

  I posted this as comments under this related thread. However, they seem to have gone unnoticed =(

  I’ve used

  ffmpeg -i myfile.avi -f image2 image-%05d.bmp

  to split myfile.avi into frames stored as .bmp files. It seemed to work except not quite. When recording my video, I recorded at a rate of 1000fps and the video turned out to be 2min29sec long. If my math is correct, that should amount to a total of 149,000 frames for the entire video. However, when I ran

  ffmpeg -i myfile.avi -f image2 image-%05d.bmp

  I only obtained 4472 files. How can I get the original 149k frames ?

  I also tried to convert the frame rate of my original AVI to 1000fps by doing

  ffmpeg -i myfile.avi -r 1000 otherfile.avi

  but this didn’t seem to fix my concern.

• How to detect Audio or Video or Both exist in converted file

  28 juillet 2016, par Khaja Hussain

  I am trying to convert mp4 or 3gp video files into Flash (flv) format (using Perl script), using following (mencoder) command :

  mencoder test.mp4 -of lavf -ovc lavc -lavcopts vcodec=flv:vbitrate=1000:mbd=2 -fps 20.80 -ofps 20.80 -oac mp3lame -lameopts abr:br=32 -srate 22050 -o test.flv

  It works fine, but some files which comes as attachments from mobile phone has problem, the converted FLV file has only audio.

  I also used ffmpeg command as follows :

  ffmpeg -i test.mp4 -ar 22050 -acodec libmp3lame -ab 32K -r 25 -vcodec flv test.flv

  This ffmpeg command helps to convert to flv, which is failed by mencoder.

  I am thinking some solution like, need to check whether converted flv has audio and video then will take action depends on it. Could you help me to solve this issue ?

  Here is some more info (log) :

  [mov,mp4,m4a,3gp,3g2,mj2 @ 0xb6b9a3a0]multiple edit list entries, a/v desync might occur, patch welcome
  ** MUXER_LAVF *************************************
  REMEMBER : MEncoder’s libavformat muxing is presently broken and can generate
  INCORRECT files in the presence of B-frames. Moreover, due to bugs MPlayer
  will play these INCORRECT files as if nothing were wrong !

  ---

  Unsupported PixelFormat 61
  Unsupported PixelFormat 53
  Unsupported PixelFormat 81
  [flv @ 0xb6b9a3a0]Codec for stream 0 does not use global headers but container format requires global headers
  [flv @ 0xb6b9a3a0]Codec for stream 1 does not use global headers but container format requires global headers
  [flv @ 0xb6b9a3a0]pts < dts in stream 0
  Error while writing frame.

  [flv @ 0xb6b9a3a0]pts < dts in stream 0
  Error while writing frame.

  [flv @ 0xb6b9a3a0]pts < dts in stream 0
  Error while writing frame.

  [flv @ 0xb6b9a3a0]pts < dts in stream 0
  Error while writing frame.

  [flv @ 0xb6b9a3a0]pts < dts in stream 0
  Error while writing frame.

  Skipping frame !

  .........................

• FFMpeg extremely slow - when called from asp.net

  9 juillet 2013, par Daveo

  I have a C# .NET website hosted on WIN2003 IIS6. This calls a .exe I have made (also in .net) using System.Diagnostics.Process which in turn calls a .bat script to convert a video into web formats (h264/MP4 and WEBM)

  ::Make MP4 ffmpeg.exe -i "%1" -y -vcodec libx264 -pix_fmt yuv420p
  -vprofile high -b:v 600k -maxrate 600k -bufsize 1200k -s 480x320 -threads 0 -acodec libvo_aacenc -b:a 128k "%2\video.mp4"

  ::Make WemM (VP8 / Vorbis) ffmpeg.exe -i "%1" -y -vcodec libvpx -b:v
  600k -maxrate 600k -bufsize 1200k -s 480x320 -threads 3 -acodec
  libvorbis -f webm "%2\video.webm"

  When I test it it seems to work fine a 70Mb input file will take about 4 minute to convert to mp4 then 6 minutes to convert to webm. Which is fine ! However whenever the customer test it the ffmpeg encoding taking HOURS (5 - 10 hours for one video) .

  When I look at windows task manager it shows a 2-3 instances of ffmpeg using cpu. When I refresh the output folder I can see the file increasing at 1Kb / second very slow. Why could this be happening ?

  my .net code

  private  bool Convert(string inputFile, string outputFolder)
  
          {
  
              string exePath = ConfigurationManager.AppSettings["BatchFile"];
  
              ProcessStartInfo startInfo = new ProcessStartInfo(exePath);
  
  
  
              startInfo.Arguments = string.Format("{0} {1}", inputFile, outputFolder);
  
              startInfo.FileName = exePath;
  
              startInfo.UseShellExecute = true;
  
              startInfo.CreateNoWindow = true;
  
  
  
  
  
              using (Process process = new Process())
  
              {
  
                  process.StartInfo = startInfo;
  
  
  
                  try
  
                  {
  
                      bool success;
  
                      int waitTimeInMinutes = int.Parse(ConfigurationManager.AppSettings["VideoConversionTimeout"]);
  
                      process.Start();
  
                      process.WaitForExit(1000 * 60 * waitTimeInMinutes); // Give up after Xmins 
  
  
  
                      success = (process.ExitCode == 0);
  
  
  
                      return success;
  
  
  
                  }
  
                  catch (Exception e)
  
                  {
  
                      log.ErrorException("Main exception", e);
  
                      return false;
  
                  }
  
              }
  
          }