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• Low performance when extracting frames from video

  25 février 2016, par Rakatan

  I am writing a video processing application and have hit a bit of a snag.

  The idea is to extract frames (images) from a video file, process them on the GPU and then write them back to a new video file.

  So far i have been successful in doing this using JavaCV.

  The only problem is that extracting the frames takes a very long time (in the 200ms region). This is way to much, as added to the GPU processing time and the time it takes to write to a new file, it results in a total process duration of about 700ms per frame.

  This is how i grab the frames :

   FFmpegFrameGrabber frameGrabber = new FFmpegFrameGrabber(videoLocation);
  
   frameGrabber.start();
  
  
  
   frameGrabber.setFrameNumber(frameNumber);
  
   frame = frameGrabber.grabImage();

  Pretty standard, nothing special, and it works. I am able to process the frame, convert it to a bitmap, etc...

  As i have said before, the bottom two instructions (setting the frame number and grabbing the image) take a very very long time. Writing the frames also takes a fair bit.

  I would greatly appreciate if anyone has any input regarding this issue. Maybe i’m not setting up something correctly, maybe there is another solution that is faster.

• ffmpeg hardcode subtitles, no subtitles but no output error

  8 février 2024, par Rafael Castelo

  I'm trying to hardcode subtitles for a project I'm working on : https://scriptme.io an mp4 files using an external SRT subtitles file.
Despite getting a succesful result as output :

  


  video:3923kB audio:975kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 1.344595%
[libx264 @ 0x63b08c0] frame I:9     Avg QP:15.65  size: 31298
[libx264 @ 0x63b08c0] frame P:609   Avg QP:20.37  size:  4283
[libx264 @ 0x63b08c0] frame B:1242  Avg QP:23.74  size:   907
[libx264 @ 0x63b08c0] consecutive B-frames:  3.3% 15.4% 23.1% 58.3%
[libx264 @ 0x63b08c0] mb I  I16..4: 21.5% 54.0% 24.5%
[libx264 @ 0x63b08c0] mb P  I16..4:  1.2%  2.7%  0.3%  P16..4: 18.7%  4.2%  1.6%  0.0%  0.0%    skip:71.4%
[libx264 @ 0x63b08c0] mb B  I16..4:  0.1%  0.1%  0.0%  B16..8: 13.9%  0.6%  0.0%  direct: 0.1%  skip:85.2%  L0:41.5% L1:56.8% BI: 1.7%
[libx264 @ 0x63b08c0] 8x8 transform intra:62.4% inter:86.2%
[libx264 @ 0x63b08c0] coded y,uvDC,uvAC intra: 36.7% 53.0% 15.0% inter: 2.2% 3.1% 0.1%
[libx264 @ 0x63b08c0] i16 v,h,dc,p: 42% 20% 13% 25%
[libx264 @ 0x63b08c0] i8 v,h,dc,ddl,ddr,vr,hd,vl,hu: 33% 15% 28%  3%  4%  6%  4%  5%  3%
[libx264 @ 0x63b08c0] i4 v,h,dc,ddl,ddr,vr,hd,vl,hu: 35% 23% 14%  4%  6%  7%  5%  4%  2%
[libx264 @ 0x63b08c0] i8c dc,h,v,p: 51% 17% 26%  6%
[libx264 @ 0x63b08c0] Weighted P-Frames: Y:0.2% UV:0.2%
[libx264 @ 0x63b08c0] ref P L0: 69.1%  9.6% 15.1%  6.1%
[libx264 @ 0x63b08c0] ref B L0: 87.2% 10.7%  2.1%
[libx264 @ 0x63b08c0] ref B L1: 97.9%  2.1%
[libx264 @ 0x63b08c0] kb/s:517.69
[aac @ 0x63b3600] Qavg: 257.742


  


  However once I play the video with any player, the subtitles aren't there.

  


  This is the command I'm using for the task

  


  ffmpeg -i https://some-bucket.s3.region.amazonaws.com/my-video.mp4 -f mp4 -vf subtitles=sub.srt subtitled-video.mp4


  


• Upload ffmpeg file output to AWS s3 using NodeJS

  29 janvier 2020, par Durrani

  The ffmpeg.output("path/file.mp4") need a string path as an argument to write the output file to it. But s3 bucket.upload(parms, ...) need a Binary File as a value to the Body: in parms JSON

  Problem : Unable to provide file data using the file path to s3 bucket in NodeJS Environment

  FFmpeg()
  
    .input("source.mp4") //video
  
    .setStartTime(startTime)
  
    .setDuration(duration)
  
    .output(output)    //output file path: string
  
    .on("end", function() {
  
      console.log("Processing finished successfully");
  
      var params = {
  
        Bucket: process.env.S3_BUCKET,
  
        Key: "videos/filename.mp4",
  
        Body: output    //binary file data to be provided not file path
  
      };
  
      const bucket = new S3({
  
        accessKeyId: process.env.S3_ACCESS_KEY_ID,
  
        secretAccessKey: process.env.S3_SECRET_ACCESS_KEY,
  
        region: process.env.S3_REGION
  
      });
  
      bucket.upload(params, function(err, data) {
  
        console.log(err, data);
  
      });
  
    })
  
    .run();