Recherche avancée

Sur d’autres sites (9699)

• ffmpeg framerate inconsistent

  16 septembre 2021, par user3190036

  ffmpeg is being run with the same arguments but different inputs in two separate places in my code. The framerate is set to 12fps with -framerate. In one case the output video matches the framerate pretty well every time. In the other case the video is coming back with 1 second of video for every 15 input frames, but again it is consistent. What could possibly be causing the discrepancy ?

  


  Arguments :
-y -framerate 12 -itsoffset -654ms -i "C :\path/%06d.JPG" -i "C :\path/audio.mp3" -map 0:v:0 -map 1:a:0 -vf scale=1280:720:force_original_aspect_ratio=decrease,pad=1280:720 :-1 :-1:color=black -acodec aac -vcodec libx264 -ar 48000 -pix_fmt yuv420p -movflags +faststart "C :\path\output.mp4"

  


  There are dozens of differences in the code that calls it but I can't understand how any of that would influence the framerate. I tried switching out the mp3 with one of an arbitrary different length to see if that had an effect but it did not. That leaves only the image inputs.

  


  edit : So it gets stranger. I reproduced both cases and modified the framerate value for each to check what happened. In almost every case I got more seconds of video than expected. I was doing these tests with 400 frames and 5 seconds of audio to ensure the lack of -shortest wasn't a factor. The only time I got a perfectly accurate framerate was when it was set to 1. In every other case (except the verbatim 12fps in the case that was always working) the video was too short by 5-15%. This makes it a bit of a mystery how either part of my code ever produced good results.

  


• How to obtain the stderr on node-fluent-ffmpeg

  14 mai 2014, par soycabanillas

  Now that the saveToFile callback param has been deprecated :

  FfmpegCommand.prototype.saveToFile = function(targetfile, callback) {
  
      if (callback) {
  
        this.options.logger.warn('saveToFile callback is deprecated, use \'end\' and \'error\' events instead');

  I’ve changed my code from this :

  new ffmpeg({ source: source })
  
              .toFormat('ogg')
  
              .saveToFile(path.normalize(targetFile), function(stdout, stderr) {
  
                  console.log('stdout', stdout);
  
                  console.log('stderr', stderr);
  
              });

  to this :

  new ffmpeg({ source: source })
  
      .toFormat('ogg')
  
      .on('end', function() {
  
          console.log('file has been converted succesfully');
  
      })
  
      .on('error', function(err) {
  
          console.log('an error happened: ' + err.message);
  
      })
  
      .saveToFile(path.normalize(targetFile));

  but I don’t know how to obtain the stderr that the old code give me as a param (stderr).
  I know that I can obtain the error message from the on ’error’ event, but I would like to get the stderr to get deeper information about what went wrong.

  Thanks in advance.

• How to use Intel QSV record screen based on ffmpeg

  18 octobre 2020, par zonda

  I want to record my screen with ffmpeg.
  
I succeeded in the normal way.
  
ffmpeg -f gdigrab -framerate 30 -draw_mouse 1 -i desktop -c:v h264 -r 30 -preset ultrafast -tune zerolatency -pix_fmt yuv420p "record.mp4"

  



  But I want use GPU record my screen now.
  
I'm trying to use Intel QSV on ffmpeg.
  
ffmpeg -f gdigrab -framerate 30 -draw_mouse 1 -i desktop -c:v h264_qsv -r 30 -tune zerolatency -pix_fmt yuv420p "record.mp4"

  



  It does not work and show :
  
[h264_qsv @ 0000000000479080] Error initializing the encoder: invalid video parameters (-15)
Error initializing output stream 0:0 -- Error while opening encoder for output stream #0:0 - maybe incorrect parameters such as bit_rate, rate, width or height

I don't know what happened.

  



  And I'm trying simple way.
  
ffmpeg -i test_input.mp4 -c:v h264_qsv -preset:v faster test_output.mp4
  
It does not work too.

  



  My computer information :
  
acer notebook : TravelMate P243-MG
  
OS : windows 7 64bits
  
CPU : Intel i5-3210M
  
Graphics card : Nvidia GT-630M

  



  Thanks in advance !