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• x264 encoding with libav

  25 mars 2014, par user3453729

  I try to encode raw image data to x264 with libav :

  AVPacket vpkt = { 0 };
  
  av_init_packet(&vpkt);
  
  
  
  int got;
  
  int ret = avcodec_encode_video2(vcodec, &vpkt, frameyuv.get(), &got);
  
  
  
  if (!ret && got && vpkt.size) {
  
      if (vpkt.pts != AV_NOPTS_VALUE) {
  
          vpkt.pts = av_rescale_q(vpkt.pts, vcodec->time_base, videost->time_base);
  
      }
  
      if (vpkt.dts != AV_NOPTS_VALUE) {
  
          vpkt.dts = av_rescale_q(vpkt.dts, vcodec->time_base, videost->time_base);
  
      }
  
  
  
      vpkt.stream_index = videost->index;
  
  
  
      if(vcodec->coded_frame->key_frame) {
  
          vpkt.flags |= AV_PKT_FLAG_KEY;
  
      }
  
      /* -> will return -22 if max_b_frames > 0 */
  
      ret = av_interleaved_write_frame(oc, &vpkt);
  
  }

  Runs fine when vcodec->max_b_frames is set to 0, but on any other value av_interleaved_write_frame returns -22 (invalid argument).

  /* will fail */
  
  c->max_b_frames = 3;
  
  /* -> ok*/
  
  c->max_b_frames = 0;

  Why ? Am i missing something ?

  Codec options are

  AVDictionary *opts = NULL;
  
  av_dict_set(&opts, "vprofile", "baseline", 0);
  
  
  
  /* ... */
  
  c->codec_type = AVMEDIA_TYPE_VIDEO;
  
  c->bit_rate = 500 * 1000;
  
  c->width = VideoWidth;
  
  c->height = VideoHeight;
  
  c->time_base.den = fps;
  
  c->time_base.num = 1;
  
  c->pix_fmt = AV_PIX_FMT_YUV420P;

  Container format is mp4.

• Using ffmpeg with Imagick

  19 mars 2014, par user3240613

  I am trying to generate thumbnails from videos in imagick, by extracting a single frame from them, using the ffmpeg application.

  I use this code currently :

  $image->newPseudoImage( null, null, 'ffmpeg:video.mp4[50]');

  It works. But it is not an ideal solution.
  I want to generate the thumbnail from a 50% position in the video, but i do not know how long the video is, so I can't do something like ffmpeg:video.mp4[500001]. And even if I knew the length, I still couldn't do it because running this ffmpeg:video.mp4[1000] takes almost 20 seconds to execute (ffmpeg:video.mp4[50] takes one or two seconds only).

  When i try to add some extra parameters like "ffmpeg:video.mp4[50] -ss 50" it returns error.

  The only other option I can think of, is using the exec to directly execute the ffmpeg command in the shell like "ffmpeg -i video.mp4 -vframes 1 -o screenshot.jpg" or something like that. Would that actually be more efficient solution than using the newpseudoimage method ?

• ffmpeg not returning duration, cant play video until complete. Stream images 2 video via PHP

  17 février 2014, par John J

  I am real struggling with ffmpeg. I am trying to convert images to video, I have an ip camera which I am recording from. The recordings are mjpegs 1 frame per image.

  I am trying to create a script in php so I can recreate a video from date to date, this requires inputting the images via image2pipe and then creating the video.

  The trouble is, ffmpeg does return the duration and start stats, so I have no way of working out when the video is done or what percentage is done. The video won't play until its finished, and its not a very good UE.

  Any ideas of how I can resolve this, the video format can be anything I am open to suggestions.

  PHP :

  //Shell command
  
  exec('cat /image/dir/*.jpg | ffmpeg -y -c:v mjpeg -f image2pipe -r 10 -i - -c:v libx264 -pix_fmt yuv420p -movflags +faststart myvids/vidname.mp4 1>vidname.txt 2>&1')
  
  
  
  //This is loaded via javascript when the video is loaded (which is failing due to stats being wrong
  
  $video_play = "<video width="\&quot;320\&quot;" height="\&quot;240\&quot;" src="\&quot;myvids/vidname.mp4\&quot;" type="\&quot;video/mp4\&quot;\" controls="\&quot;controls\&quot;" preload="\&quot;none\&quot;"></video>";

  Javascript :

  //Javascript to create the loop until video is loaded
  
  <code class="echappe-js">&lt;script&gt;<br />
  
             $(document).ready(function() {<br />
  
                  var loader = $(&quot;#clip_load&quot;).percentageLoader();<br />
  
                  $.ajaxSetup({ cache: false }); // This part addresses an IE bug. without it, IE will only load the first number and will never refresh<br />
  
                  var interval = setInterval(updateProgress,1000);<br />
  
                  function updateProgress(){ $.get( &quot;&amp;#39;.base_url().&amp;#39;video/getVideoCompile_Process?l=&amp;#39;.$vid_name.&amp;#39;-output.txt&amp;amp;t=per&quot;, function( data ) { if(data=&gt;\&amp;#39;100\&amp;#39;){ $(&quot;#clip_load&quot;).html(\&amp;#39;&amp;#39;.$video_play.&amp;#39;\&amp;#39;); clearInterval(interval); }else{loader.setProgress(data); } });                    }<br />
  
              });<br />
  
              &lt;/script&gt;
  
  

  PHP (page is called via javascript :

  //This is the script which returns the current percentage
  
  $logloc = $this->input->get('l');
  
  $content = @file_get_contents($logloc);
  
  
  
  if($content){
  
      //get duration of source
  
      preg_match("/Duration: (.*?), start:/", $content, $matches);
  
  
  
      $rawDuration = $matches[1];
  
  
  
      //rawDuration is in 00:00:00.00 format. This converts it to seconds.
  
      $ar = array_reverse(explode(":", $rawDuration));
  
      $duration = floatval($ar[0]);
  
      if (!empty($ar[1])) $duration += intval($ar[1]) * 60;
  
      if (!empty($ar[2])) $duration += intval($ar[2]) * 60 * 60;
  
  
  
      //get the time in the file that is already encoded
  
      preg_match_all("/time=(.*?) bitrate/", $content, $matches);
  
  
  
      $rawTime = array_pop($matches);
  
  
  
      //this is needed if there is more than one match
  
      if (is_array($rawTime)){$rawTime = array_pop($rawTime);}
  
  
  
      //rawTime is in 00:00:00.00 format. This converts it to seconds.
  
      $ar = array_reverse(explode(":", $rawTime));
  
      $time = floatval($ar[0]);
  
      if (!empty($ar[1])) $time += intval($ar[1]) * 60;
  
      if (!empty($ar[2])) $time += intval($ar[2]) * 60 * 60;
  
  
  
      //calculate the progress
  
      $progress = round(($time/$duration) * 100);
  
      if ($this->input->get('t')=='per'){
  
          echo $progress;
  
      }else{
  
              echo "Duration: " . $duration . "<br />";
  
              echo "Current Time: " . $time . "<br />";
  
      echo "Progress: " . $progress . "%";}
  
  }else{ echo "cannot locate";}

  Thanks