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• How to Generate accurate thumbnails with FFMPEG

  5 juillet 2023, par Caloux Fld

  I am using FFmpeg for generating thumbnails map.

  


  I need to generate a thumbnail for every second. Here is code i use on Windows :

  


  ffmpeg -i "C:\temp\MyVideo.mp4" -vf "drawtext=fontfile=../Fonts/calibri.ttf: text=%%`
`{n}: r=25: x=(w-tw)/2: y=h-lh-122: fontsize=295: fontcolor=Red:   box=0:` `boxcolor=Black,fps=1/1" -s 400x300 -vcodec ppm -f image2pipe - | montage -  -`
    `tile 10x -geometry 200x+0+0 C:\temp\Thumbnailer.jpg`


  


  Code Work's Fine , generate a thumbnails map with piping FFMPEG+Imagemagick (montage).
In ffmpeg i burn the frame number to check accuracy.

  


  Only problem is FFMPEG start generating at frames 12, 37, 62, 87...(video is 25 fps).

  


  How to start generating thumbnails at first frame #1 accurate ?

  


  In FFMPEG i try options like -ss 00:00:00.0 but FFMPEG start always at frame 12.
Only solution i found is to generate all frames (25fps) and post process to keep frames number 1,25,50... but very slow post process...

  


  My FFMPEG version : ffmpeg version N-88153-ga4743d2574-Reino

  


• Heroku ffmpeg buildpack

  20 octobre 2015, par Manuel Quintanilla

  Putting together the video upload section in my rails app and am having some issues with video play on mobile phones. Im using

  paperclip-av-transcoder, s3 and  Heroku

  On my laptop I can visit the page and see the video thumbnails and play the videos only because I have previously installed ffmpeg to my machine.

  Remotely on Heroku I’ve set the appropriate buildpacks for ffmpeg and have run push heroku master to install the buildpacks - Now when I visit the page on my mobile iPhone I don’t get a thumbnail but when I play the video it plays - on the other hand when I visit the page on my Android phone I don’t get a thumbnail and the video dose not play but I can upload mp4s on Android.

  Check out my set up here : Heroku ffmpeg buildpacks for video uploads

  It seems I don’t have the proper buildpack setup or some other heroku setting with ffmpeg.

  Any suggestions ? Thanks in advance !

• fluent-ffmpeg module : "end" event does not fire

  6 décembre 2015, par ndugger

  I’m using the fluent-ffmpeg npm module

  I’ve POSTed a video from my client, and am using new stream.Readable to "read" the video Buffer.

  ffmpeg is converting and saving the file, and everything seems beautiful, but the "end" event never fires.

  My code is as follows :

  const videoStream = new stream.Readable({
  
      read: function (n) {
  
          this.push(myVideoBuffer);
  
      }
  
  });
  
  
  
  ffmpeg(videoStream)
  
  .on('progress', e => console.log(e))
  
  .on('end', () => {
  
      console.log('ended')
  
      videoStream.destroy();
  
  })
  
  .on('error', e => console.error(e))
  
  .save(`${process.cwd()}/media/videos/${Date.now()}.mp4`);

  I get a log on every progress event, and it does save the video, but the "end" event’s callback never gets called.

  I assume this is a bug, since everything else works just fine.