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• mencoder generate mp4 h.264 from jpg playback stops in html videotag chrome

  10 septembre 2013, par jedimorten

  So I have some images from which I create a video with mencoder.

  mencoder -idx -nosound -noskip -of lavf -lavfopts format=mp4 -ovc x264 -x264encopts pass=1:bitrate=2000:crf=24 -o output.mp4 -mf fps=15 'mf://@files.txt'

  (where files.txt is a list of all the files sorted in the right order)

  The videos is created without problems, it plays fine in desktop-player like vlc, but in chrome (on mac) and chromium (ubuntu) some of the videoes has "breakpoints" in which the video just stops.

  Take a look at this fiddle.

  I made an ugly hack (see fiddle) to force a continued play even if the video is damaged, but this does not look very nice when the video has a lot of them "breakpoints".

  For several reasons I need to be using html, so flash would only be a last last resort.
  Any views on what may be causing these breakpoints ? Or a nicer ugly hack to force contiuned playback ?

• 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 ?

• Resize jwplayer according to ffmpeg video dynamically

  15 janvier 2014, par pkumar

  I'm using jwplayer, ffmpeg and crtmpserver to do live streaming. I was wondering if it is possible to dynamically resize the jwplayer according to the video being streamed by ffmpeg. For example let's say following ffmpeg command is being used to stream video :

  ffmpeg -re -i 'myVideo.mp4' -vf scale=30:30 -vcodec flv -acodec copy -s 30x30 -f flv rtmp://localhost/flvplayback/livestream

  Jwplayer side of code :

  <code class="echappe-js">&lt;script type=&quot;text/javascript&quot;&gt;<br />
  
      jwplayer(&quot;myElement&quot;).setup({<br />
  
        playlist: [{<br />
  
          image: &quot;/uploads/myPoster.jpg&quot;,<br />
  
          sources: [{<br />
  
              file: &quot;/uploads/myManifest.smil&quot;,<br />
  
              type: &quot;rtmp&quot;<br />
  
            },{<br />
  
            file: &quot;/uploads/myVideo.mp4&quot;<br />
  
             }]<br />
  
        }],<br />
  
        primary: &quot;flash&quot;,<br />
  
        listbar: {<br />
  
            position: &amp;#39;right&amp;#39;,<br />
  
            size: 100<br />
  
        },<br />
  
        stretching: &quot;exactfit&quot;<br />
  
  });<br />
  
  &lt;/code&gt;&lt;/pre&gt;<br />
  
  <br />
  
  &lt;p&gt;Now, since ffmpeg is streaming video with -s as 30x30, video is too blur. So, is it possible to resize the jwplayer to fit the video; jwplayer size should be reduced in this case.<br />
  
  I tried using &lt;code&gt;jwplayer.resize()&lt;/code&gt; based on &lt;code&gt;jwplayer().getCurrentQuality()&lt;/code&gt; but not sure how to use it in this case.&lt;/p&gt;