Recherche avancée

Sur d’autres sites (7286)

• python opencv + ffmpeg makes cpu more busy

  15 juillet 2022, par shao wenzhi

  I use cv2 to read frames of local video, then use ffmpeg to push the stream to remote rtmp server.

  


  The command is :

  


  command = ['ffmpeg',
           '-y', '-an',
           '-f', 'rawvideo',
           # '-vcodec', 'rawvideo',
           '-pix_fmt', 'bgr24',
           '-s', sizeStr,
           '-r', '25',
           '-i', '-',
           # '-c:v', 'libx264',
           # '-pix_fmt', 'yuv420p',
           '-preset', 'ultrafast',
           '-f', 'flv',
           rtmp]


  


  I found that compared with pushing the video directly through ffmpeg, the CPU occupation of "cv2 + ffmpeg" is much more higher. which is : ffmpeg : 5% CPU, cv2 + ffmpeg : 18% CPU

  


  One possible cause is that cv2 turns the frame into BGR, and the ffmpeg turns it into RBG back again, because I found when I removed the option '-pix_fmt', 'bgr24', the CPU occupation drops into 5%, but the video pulled from server turns out to be strange, like this :

  


  

  


  Is there any method to reduce the cost of converting BGR into RGB ??

  


• avcodec : Suppress deprecation warnings from avcodec_alloc_frame()

  4 février 2014, par Diego Biurrun

  avcodec : Suppress deprecation warnings from avcodec_alloc_frame()
  The function is itself obsolete and slated for removal.
  

  • [DBH] libavcodec/utils.c

• How to render animation using Javascript ?

  30 novembre 2018, par user9964622

  I have created animation using tweenjs and createjs libraries createjs and tweenjs, createjs now, I’d like to convert these animations to video files (MPEG4, or other, doesn’t matter) or how can I render it in the backend using nodejs ?

  Here is the solution I have tried so far using ffmpeg server

  test4.js

  (function () {
  
      "use strict";
  
  
  
      var framesPerSecond = 60;
  
      var numFrames = 20; //framesPerSecond * 60 * 2;
  
      var thickness = 100;
  
      var speed = 4;
  
      var frameNum = 0;
  
  
  
      var canvas = document.getElementById("c");
  
      var ctx = canvas.getContext("2d");
  
      canvas.width = 500;
  
      canvas.height = 500;
  
  
  
      var progressElem = document.getElementById("progress");
  
      var progressNode = document.createTextNode("");
  
      progressElem.appendChild(progressNode);
  
  
  
      function onProgress(progress) {
  
        progressNode.nodeValue = (progress * 100).toFixed(1) + "%";
  
      }
  
  
  
      function showVideoLink(url, size) {
  
        size = size ? (" [size: " + (size / 1024 / 1024).toFixed(1) + "meg]") : " [unknown size]";
  
        var a = document.createElement("a");
  
        a.href = url;
  
        var filename = url;
  
        var slashNdx = filename.lastIndexOf("/");
  
        if (slashNdx >= 0) {
  
          filename = filename.substr(slashNdx + 1);
  
        }
  
        a.download = filename;
  
        a.appendChild(document.createTextNode(url + size));
  
        document.body.appendChild(a);
  
      }
  
  
  
      var capturer = new CCapture( {
  
        format: 'ffmpegserver',
  
        //workersPath: "3rdparty/",
  
        //format: 'gif',
  
        verbose: false,
  
        framerate: framesPerSecond,
  
        onProgress: onProgress,
  
        //extension: ".mp4",
  
        //codec: "libx264",
  
      } );
  
      capturer.start();
  
  
  
      function render() {
  
  
  
        var stage = new createjs.Stage("c");
  
        var circle = new createjs.Shape();
  
        circle.graphics.beginFill("Crimson").drawCircle(0, 0, 50);
  
        circle.x = 100;
  
        circle.y = 100;
  
        stage.addChild(circle);
  
        createjs.Tween.get(circle, {loop: true})
  
          .to({x: 400}, 1000, createjs.Ease.getPowInOut(4))
  
          .to({alpha: 0, y: 75}, 500, createjs.Ease.getPowInOut(2))
  
          .to({alpha: 0, y: 125}, 100)
  
          .to({alpha: 1, y: 100}, 500, createjs.Ease.getPowInOut(2))
  
          .to({x: 100}, 800, createjs.Ease.getPowInOut(2));
  
        createjs.Ticker.setFPS(60);
  
        createjs.Ticker.addEventListener("tick", stage);
  
        capturer.capture(canvas);
  
  
  
        ++frameNum;
  
        if (frameNum === numFrames) {
  
          capturer.stop();
  
          capturer.save(showVideoLink);
  
        } else {
  
          requestAnimationFrame(render);
  
        }
  
      }
  
      requestAnimationFrame(render);
  
    }());

  here is html test4.html

    
  
      
  
    
  
    
  
      <canvas></canvas>
  
      <div>-</div>
  
    
  
    <code class="echappe-js">&lt;script src=&quot;http://localhost:8081/ffmpegserver/CCapture.js&quot;&gt;&lt;/script&gt;
    
  &lt;script src=&quot;http://localhost:8081/ffmpegserver/ffmpegserver.js&quot;&gt;&lt;/script&gt;
  
    &lt;script src=&quot;https://code.createjs.com/1.0.0/createjs.min.js&quot;&gt;&lt;/script&gt;
  
    &lt;script src='http://stackoverflow.com/feeds/tag/test4.js'&gt;&lt;/script&gt;
  
  

  when I run my app, it renders very quickly and when I download the converted mp4 file it contains zero MB.

  for reference, u can test by just cloning this repo ffmpeg server repository and add the above files to the public folder

  What am I doing wrong in my code ???