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• Using ffprobe to get number of keyframes in raw AVI file *without* processing entire file ?

  26 juillet 2018, par aggieNick02

  This question and answer cover how to get the framecount and keyframe count from an AVI file, which is very useful. I’ve got a raw AVI file and want to count the number of keyframes (equivalent to non-dropped frames for raw AVI), but it takes a long time to process through a raw AVI file.

  There is some way to get this information without fully processing the file, as VirtualDub provides both framecount and key framecount in the file information, as well as total keyframe size, almost instantly for a 25-second raw 1920x1080 AVI. But ffprobe requires count_frames to populate nb_read_frames, which takes some good processing time.

  I can do some math with the file’s size and the frame’s width/height/format to get a fairly good estimate of the number of frames, but I’m worried the overhead of the container could be enough to throw the math off for very short clips. (For my 25 second clip, I get 1286.12 frames, when there are really 1286.)

  Any thoughts on if there is a way to get this information programatically with ffprobe or ffmpeg without processing the whole file ? Or with another API on windows ?

• From URL of Video GetThumbnail Using Nreco

  8 février 2016, par Muhammad Abid Fahad

  I working on a sharepoint project in which i have to upload the videos in the document library as videoset. after creating a video set i have have to upload the video and fetch the thumbnail from the video and upload it. video is uploaded succesfully using

  spfile = item.Folder.Files.Add(fuUpload.FileName, fuUpload.PostedFile.InputStream, true);

  I am using using Nreco to get thumbnail from the video. However my code works fine on local machine but its giving error "http://mysite/Download/abc/abc.mp4 : Server returned 401 Unauthorized (authorization failed) (exit code : 1)" when i am using my application from other pc browsers.

  ffMpeg.GetVideoThumbnail(videoPath, ms, 10) ; the error line.

  here is the code i am using

  private MemoryStream SaveThumbnail(string videoPath) 
  
      {
  
          MemoryStream ms; 
  
          try 
  
          {
  
              videoPath = "http://mysitehttp/Download/abc/abc.mp4"
  
              ms = new MemoryStream();
  
              SPSecurity.RunWithElevatedPrivileges(delegate() {
  
  
  
                  var ffMpeg = new NReco.VideoConverter.FFMpegConverter();
  
                  ffMpeg.GetVideoThumbnail(videoPath, ms, 10); 
  
              });
  
  
  
  
  
          }
  
          catch(Exception ex)
  
          {
  
              throw ex;
  
          }
  
  
  
          return ms;
  
      }

• How to use ffmpeg in nodejs to merge .m4a and .m4v in .mkv

  30 juin 2019, par Rodrigo

  I’m using the script below to download vimeo’s streaming.

  • https://gist.github.com/mistic100/895f6d17b1e193334882a4c37d0d7748 *

  The problem is that the script downloads the various .m4s fragments and creates an .m4a file for audio and .m4v for video. So I have to use the ffmpeg command manually through cmd to merge them into a single .mkv file

  I would like to add a command line in the script so that it would be done automatically. I’ve tried several different commands and combinations between them like .exec, .execFile, .spawn, all unsuccessful

  Same examples :

  1)using execFile

  const child = execFile('ffmpeg', ['-i', 'input.m4v' , '-i' , 'input.m4a' , '-c' , 'copy' , 'output.mkv' ], (error, stdout, stderr) => {
  
      if (error) {
  
          console.error('stderr: =============================', stderr);
  
          throw error;
  
      }
  
      console.log('stdout: ==========================', stdout);
  
  });
  
  
  
  console.log('here');

  2)using exec

  const child = exec('ffmpeg', ['-i', 'input.m4v' , '-i' , 'input.m4a' , '-c' , 'copy' , 'output.mkv', (error, stdout, stderr) => {
  
      if (error) {
  
          console.error('stderr: =============================', stderr);
  
          throw error;
  
      }
  
      console.log('stdout: ==========================', stdout);
  
  });
  
  
  
  console.log('here');

  3)using spawn

  var cmd = 'D:\vimeo\ffmpeg';
  
  
  
  var args = [
  
      '-i', 'D:\vimeo\input.m4a',
  
      '-i', 'D:\vimeo\input.m4v', 
  
      '-c', 'copy', 'D:\vimeo\output.mkv'
  
  ];
  
  
  
  var proc = spawn(cmd, args);
  
  
  
  proc.stdout.on('data', function(data) {
  
      console.log(data);
  
  });
  
  
  
  proc.stderr.on('data', function(data) {
  
      console.log(data);
  
  });
  
  
  
  proc.on('close', function() {
  
      console.log('finished');
  
  });

  What am I doing wrong ?

  ---

  The error mesangens are

  1)

  D:\vimeo\vimeo-downloader.js:94
  
  const child = execFile('ffmpeg', ['-i', 'input.m4v' , '-i' , 'input.m4a' , '-c' , 'copy' , 'output.mkv' ], (error, stdout, stderr) => {
  
                ^
  
  
  
  ReferenceError: execFile is not defined
  
      at Object.<anonymous> (D:\vimeo\vimeo-downloader.js:94:15)
  
      at Module._compile (internal/modules/cjs/loader.js:776:30)
  
      at Object.Module._extensions..js (internal/modules/cjs/loader.js:787:10)
  
      at Module.load (internal/modules/cjs/loader.js:653:32)
  
      at tryModuleLoad (internal/modules/cjs/loader.js:593:12)
  
      at Function.Module._load (internal/modules/cjs/loader.js:585:3)
  
      at Function.Module.runMain (internal/modules/cjs/loader.js:829:12)
  
      at startup (internal/bootstrap/node.js:283:19)
  
      at bootstrapNodeJSCore (internal/bootstrap/node.js:622:3)
  
  </anonymous>

  2)

  D:\vimeo\vimeo-downloader.js:100
  
  });
  
   ^
  
  
  
  SyntaxError: Unexpected token )
  
      at Module._compile (internal/modules/cjs/loader.js:721:23)
  
      at Object.Module._extensions..js (internal/modules/cjs/loader.js:787:10)
  
      at Module.load (internal/modules/cjs/loader.js:653:32)
  
      at tryModuleLoad (internal/modules/cjs/loader.js:593:12)
  
      at Function.Module._load (internal/modules/cjs/loader.js:585:3)
  
      at Function.Module.runMain (internal/modules/cjs/loader.js:829:12)
  
      at startup (internal/bootstrap/node.js:283:19)
  
      at bootstrapNodeJSCore (internal/bootstrap/node.js:622:3)

  3)

  D:\vimeo\vimeo-downloader.js:102
  
  var proc = spawn(cmd, args);
  
             ^
  
  
  
  ReferenceError: spawn is not defined
  
      at Object.<anonymous> (D:\vimeo\vimeo-downloader.js:102:12)
  
      at Module._compile (internal/modules/cjs/loader.js:776:30)
  
      at Object.Module._extensions..js (internal/modules/cjs/loader.js:787:10)
  
      at Module.load (internal/modules/cjs/loader.js:653:32)
  
      at tryModuleLoad (internal/modules/cjs/loader.js:593:12)
  
      at Function.Module._load (internal/modules/cjs/loader.js:585:3)
  
      at Function.Module.runMain (internal/modules/cjs/loader.js:829:12)
  
      at startup (internal/bootstrap/node.js:283:19)
  
      at bootstrapNodeJSCore (internal/bootstrap/node.js:622:3)   
  
  </anonymous>