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• How well does FFmpeg scale ? Any examples ?

  17 juin 2020, par Pepper

  I'm currently working on the server side of an augmented reality project. It's a lot like http://www.livingsasquatch.com/. I'm using PHP/MySQL and FFmpeg to capture the webcam video and encoding it to .flv.

  



  Basically Flash uploads the video as a long series of .jpg images. PHP then takes those images, generates a few thumbnails and passes them through FFmpeg which converts them to a single .flv file.

  



  Here is the FFmpeg code :

  



  $ffmpeg_images = $image_directory.'/image%d.jpg';

@unlink($video_directory."/$video_id.flv"); 
$ffmpeg_video = $video_directory."/$video_id.flv";
$ffmpeg_string = FFMPEG_PATH." -f image2 -i $ffmpeg_images -f flv $ffmpeg_video";

@exec($ffmpeg_string);


  



  This seems to be working nicely in my tests, but I don't know how we'll it will scale. Since this is my first time using FFmpeg, I don't know if video encoding this way will bring the server to its knees.

  



  Does anyone have experience with FFmpeg on a high traffic site ?

  



  Is there a better way of handling this type of Webcam to .flv conversion ?

  



  Are there any examples of FFmpeg being used on a high traffic site ?

  


• Replace frames in an AVI with Java

  12 juillet 2018, par webuster

  I’m recording some screencasts and my crap recorder (Camtasia) recorded 2000 videos with a brief black flash (2-3 frames) at, or near the beginning of each.

  I’m looking for a way to automate the replacement of the black frames inside each video with FFmpeg, and I can currently detect which frames are black.

  The problem I have is now : How can I replace frame number X with the content of frame number X-1 in an AVI video ? Not looking to shorten the video, but just to replace a frame in-place.

  Here’s what I have so far :

  FFmpegFrameGrabber g = new FFmpegFrameGrabber("res/video.avi");
  
  g.start();
  
  
  
  FFmpegFrameRecorder recorder = new FFmpegFrameRecorder(new FileOutputStream(new File("res/video_out.avi")), g.getImageWidth(), g.getImageHeight(), 2);
  
  
  
  recorder.setFormat("avi");
  
  recorder.setPixelFormat(AV_PIX_FMT_YUV420P);
  
  recorder.setFrameRate(30);
  
  recorder.setVideoCodec(AV_CODEC_ID_H264);
  
  recorder.setVideoQuality(10);
  
  recorder.setSampleFormat(AV_SAMPLE_FMT_FLTP);
  
  recorder.setSampleRate(48000);
  
  recorder.setAudioCodec(AV_CODEC_ID_AAC);
  
  recorder.setAudioQuality(10);
  
  
  
  g.setFrameNumber(1);
  
  recorder.setFrameNumber(2);
  
  recorder.record(g.grab());
  
  
  
  g.close();
  
  recorder.close();
  
  recorder.release();

  And I’m getting a video back with empty frames (not even black), so I might be messing something here.

  Anyone with experience with FFmpeg ?

• hls.js - how to increase the preloaded buffer size

  4 novembre 2020, par mmm

  I am generating hls content using ffmpeg from a remote src and I keep experience lagging that I do not understand in the browser.

  



  For instance, even though there are say out8.ts, out9.ts ... hls.js player will be on say out7.ts and not load out8.ts or out9.ts.

  



  It waits until out7.ts has almost finished playing and then it tries to load the out.m3u8 which will contain out8.ts and possibly out9.ts. But it does this so late, it eventually leads to lagging. I am doing this on localhost and in an efficient manner.

  



  This seems to repeat itself once it starts to occur.

  



  How can I make hls.js ask for the m3u8 more often and buffer what ever is present ? Or as much as possible ?

  



  Also if there is already say 1-10.ts files, how can I make hls.js start on not the last one ( although closer to live ) but maybe on 5.ts so it won't run into this tight deadline issues concerning the next updated m3u8 and possibly lenghty 11.ts preventing it from buffering it ?

  



  My options :

  



      new Hls({
            autoStartLoad: true,
            debug: App.isDevelopment(),
            manifestLoadingTimeOut : 60000,
            /*manifestLoadingMaxRetry : 9,*/
            manifestLoadingRetryDelay : 500,
            levelLoadingTimeOut : 60000,
            /*levelLoadingMaxRetry : 9,*/
            levelLoadingRetryDelay : 500,

            fragLoadingTimeOut : 60000,
            /*fragLoadingMaxRetry : 6,*/
            fragLoadingRetryDelay : 250,
            startFragPrefetch : true
    });


  



  Is there any difference in using clapper instead of hls.js regarding controlling such things ?