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• How do I queue file for ffmpeg on Node.js ?

  12 août 2022, par Hall45

  I need to encode/convert many videos on my (linux) server. And FFMPEG is resource intensive.
I am running Node.js and using fluent-ffmpeg

  


      const Ffmpeg = require("fluent-ffmpeg");
    videos.forEach(video=> {
        covertVideo(filename, (compressionResult)=>{
            //do something here
        });
    });
    function covertVideo(filename, callback){
        var ffmpeg = new FfmpegCommand(filename);
        ffmpeg.setFfmpegPath(pathToFfmpeg);
        ffmpeg.addOptions("-threads 1")
        .fps(23)
        .complexFilter([
            "scale=w='if(gt(a,0.75),240,trunc(320*a/2)*2)':h='if(lt(a,0.75),320,trunc(240/a/2)*2)',pad=w=240:h=320:x='if(gt(a,0.75),0,(240-iw)/2)':y='if(lt(a,0.75),0,(320-ih)/2)':color=black[scaled]"
        ])
        .on('error', function(err) {
            console.log('An error occurred: ' + err.message);
            return callback(false);
          })
        .on('end', function() {
            console.log('Compression finished !');
            return callback(true);
          })
        .save("./tmp/"+filename);
    }



  


  So, I am using foreach loop to iterate through the file to be encoded. At each loop this function above is called.

  


  The problem here is that the foreach enters the second loop and start encoding when the first is still being encoded by FFMPEG thereby showing "Resource temporarily unavailable error".

  


  Is there a way to queue files sent to FFMPEG so that next file is encoded when the previous is done and not concurrently.

  


  OR

  


  Is there a way for the Nodejs foreach to wait for ffmpeg to finish the first video before proceeding to the next loop.

  


• How to speed up black video creation with FFMPEG ?

  2 décembre 2017, par Rick Sullivan

  I have been generating static black videos as backgrounds using FFMPEG’s color source. This works fine for smaller and shorter videos, but I need to be able to generate long 1080p black videos quickly.

  For example, I can generate a two hour long 1080p@30fps video using :

  ffmpeg -f lavfi -i color=black:s=1920x1080:r=30 -t 7200 test.mp4

  But this will take over 45 minutes to run.

  There are options that speed up runtime, like using the ultrafast preset :

  ffmpeg -f lavfi -i color=black:s=1920x1080:r=30 -preset ultrafast -t 7200 test.mp4

  Which will take around 20 minutes to run. Better, but not good enough for doing this en masse.

  Are there any other options to drastically speed up runtime ?

  Intuitively, I am generating a static video where only video duration varies, so it seems like there should be an approach that is restricted only by disk write speed. All of these options are very CPU intensive and seem to be doing more processing than is necessary for my use case.

• avcodec/bmp : Fix runtime error : negation of -2147483648 cannot be represented in...

  21 février 2017, par Michael Niedermayer

  avcodec/bmp : Fix runtime error : negation of -2147483648 cannot be represented in type ’int’ ; cast to an unsigned type to negate this value to itself
  There is code checking height and width later, leaving an invalid value invalid
  
  is thus fine.
  Fixes : 635/clusterfuzz-testcase-6225161437052928
  
  Found-by : continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/targets/ffmpeg
  
  Signed-off-by : Michael Niedermayer <michael@niedermayer.cc>
  

  • [DH] libavcodec/bmp.c