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• JavaCV FFmpegFrameGrabber preload audio

  1er juillet 2015, par James

  I have an application that streams video data to a RTMP server using javacv’s FFmpegFrameRecorder. I want to add some audio to this stream from a separate file - a short sound clip that I want to play on repeat.

  Given the sound clip is very short, I want to preload the audio data into memory and just loop over it - so I can avoid excessive IO etc.

  I’ve attempted to add audio to the stream using javacv’s FFmpegFrameGrabber, as prescribed on multiple tutorials.

  The addition of audio works perfectly if I don’t attempt to preload/cache any of the audio data, for example :

  private FFmpegFrameRecorder frameRecorder;
  
  private FFmpegFrameGrabber frameGrabber;
  
  
  
  ...
  
  //frameRecorder and frameGrabber setup during initialization
  
  ...
  
  
  
  public void record(IplImage image) {
  
          try {
  
              frameRecorder.record(image);
  
              Frame frame = frameGrabber.grabFrame();
  
              if(frame == null) {
  
                  frameGrabber = new FFmpegFrameGrabber("audioFileHere.wav");
  
                  frameGrabber.start();
  
                  frame = frameGrabber.grabFrame();
  
              }
  
              frameRecorder.record(frame);
  
          } catch (FrameRecorder.Exception e) {
  
              log.error(getMarker(FATAL), "Can't record frame!", e);
  
          } catch (FrameGrabber.Exception e) {
  
              log.error(getMarker(FATAL), "Can't record frame!", e);
  
          }
  
  }

  However, if I try to preload the audio data I get garbage sound being played :

  private FFmpegFrameRecorder frameRecorder;
  
  private List<framedata> audioData;
  
  
  
  private static final class FrameData {
  
      public final Buffer[] samples;
  
      public final Integer sampleRate;
  
      public final Integer audioChannels;
  
  
  
      //Constructors, getters and setters here
  
  }
  
  
  
  ...
  
      //frameRecorder setup during initialization
  
      audioData = new ArrayList&lt;>();
  
      FFmpegFrameGrabber audioGrabber = new FFmpegFrameGrabber("audioFileHere.wav");
  
      try {
  
          audioGrabber.start();
  
          Frame frame;
  
          while ((frame = audioGrabber.grabFrame()) != null) {
  
              Buffer[] buffers = frame.samples;
  
              Buffer[] copiedBuffers = new Buffer[buffers.length];
  
              for (int i = 0; i &lt; buffers.length; i++) {
  
                  copiedBuffers[i] = ((ShortBuffer) buffers[i]).duplicate();
  
              }
  
              FrameData frameData = new FrameData(copiedBuffers, frame.sampleRate, frame.audioChannels);
  
              audioData.add(frameData);
  
          }
  
      } catch (FrameGrabber.Exception e) {
  
          e.printStackTrace();
  
      }
  
  ...
  
  
  
  private int frameCount = 0;
  
  
  
  public void record(IplImage image) {
  
      frameCount++;
  
      try {
  
          FrameData frameData = audioData.get(frameCount % audioData.size());
  
          frameRecorder.record(image);
  
          frameRecorder.record(frameData.sampleRate, frameData.audioChannels, frameData.samples);
  
      } catch (FrameRecorder.Exception e) {
  
          log.error(getMarker(FATAL), "Can't record frame!", e);
  
      }
  
  }
  
  </framedata>

  NOTE : I have to deep copy the Frame object because FFmpegFrameGrabber.grabFrame() recycles a single Frame object

  Can someone explain why this doesn’t work and/or how I could achieve the desired result ?

• FFMPEG & ScrollMagic : Safari bug

  27 novembre 2020, par gusv7

  I got this site where video playback is linked to scroll position. I'm using a FFMPEG-encoded .mp4 file and ScrollMagic to handle the scroll event. It works perfectly on Chrome, Opera and FF, but crashes on Safari : the animation is delayed and the video disappears once it reaches the end of the playback on Safari OS. It also doesn't show on iOS, not in Safari or Chrome... :/

  


  Here's the markup :

  


  <section class="shaka-container padding-x-lg flex-end">&#xA;  <div class="shaka">&#xA;    <video src="/assets/maozinha.mp4" type="video/mp4" playsinline="true"></video>&#xA;  </div>&#xA;</section>&#xA;

  


  The JS :

  


  &#xA;<code class="echappe-js">&lt;script src=&quot;https://cdnjs.cloudflare.com/ajax/libs/gsap/3.5.1/gsap.min.js&quot;&gt;&lt;/script&gt;&#xA;&#xA;&lt;script src=&quot;https://cdnjs.cloudflare.com/ajax/libs/ScrollMagic/2.0.8/ScrollMagic.min.js&quot; integrity=&quot;sha512-8E3KZoPoZCD&amp;#x2B;1dgfqhPbejQBnQfBXe8FuwL4z/c8sTrgeDMFEnoyTlH3obB4/fV&amp;#x2B;6Sg0a0XF&amp;#x2B;L/6xS4Xx1fUEg==&quot; crossorigin=&quot;anonymous&quot;&gt;&lt;/script&gt;&#xA;&#xA;&lt;script&gt;&amp;#xA;  // Shaka Animation&amp;#xA;    const intro = document.querySelector(&amp;#x27;.shaka&amp;#x27;);&amp;#xA;    const video = intro.querySelector(&amp;#x27;video&amp;#x27;);&amp;#xA;&amp;#xA;    // SCROLL MAGIC&amp;#xA;&amp;#xA;    const controller = new ScrollMagic.Controller();&amp;#xA;&amp;#xA;    // Scenes&amp;#xA;    const scene = new ScrollMagic.Scene({&amp;#xA;      duration: 0,&amp;#xA;      triggerElement: intro,&amp;#xA;      triggerHook: 0,   &amp;#xA;    })&amp;#xA;    .addTo(controller);&amp;#xA;&amp;#xA;    // Video Animation&amp;#xA;&amp;#xA;    let accelamount = 0.5;&amp;#xA;    let scrollpos = 0;&amp;#xA;    let delay = 0;&amp;#xA;&amp;#xA;    scene.on(&amp;#x27;update&amp;#x27;, e =&gt; {&amp;#xA;      scrollpos = e.scrollPos / 1000;&amp;#xA;    });&amp;#xA;&amp;#xA;    setInterval(() =&gt; {&amp;#xA;      delay &amp;#x2B;= (scrollpos - delay) * accelamount;&amp;#xA;      video.currentTime = delay;&amp;#xA;    }, 24);&amp;#xA;&lt;/script&gt;&#xA;

  


  I wonder if the video encoding is the issue or how Safari processes the video playback ? I've used the following encoding for the video :

  


  First :
ffmpeg -i ~/assets/mao-final.mp4 -vf scale=960:-2 -movflags faststart -vcodec libx264 -crf 20 -g 1 -pix_fmt yuv420p mao-final-960.mp4

  


  Then,
ffmpeg -i ~/assets/mao-final.mp4 -vf scale=960:-2 -movflags faststart -vcodec libx264 -crf 20 -g 1 -pix_fmt yuv420p maozinha.mp4

  


  I'm considering changing it to a canvas animation if I can't get to a solution. Please help !

  


• Anomalie #4546 (Nouveau) : image_recadre perd l’EXIF de rotation

  4 septembre 2020, par jluc -

  Alors que image_reduire propage les données EXIF de rotation, image_recadre les perd. Cela nuit grandement au rendu final.