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• FFMPEG scaling video disable viewing it in HTML player while process is not ended, for video transcoding on the fly

  6 juillet 2022, par Lucas F

  Good day all,

  


  I'm working on a video player with 1080p original video files, and I would like to change their resolution on the fly :

  


  Actually I host all my original video files under a web mp4 1080p format, and I would like to be able to offer 720p, 480p, etc ... qualities.

  


  So I started to look for tutorials about video transcoding on the fly and I found the FFMPEG tool.

  


  I'm actually using the following command to scale videos - to 720p for e.g. :

  


  ffmpeg -i input.mp4 -vf scale=-1:720 output.mp4


  


  The problem is, once FFMPEG starts scaling it, I have to wait the end of the process before being able to play the video. Do you know if there is any parameter for this command to allow playing the video while it's under scaling ?

  


  Or any workaround that can help me doing this ?

  


  Thank you in advance for your help !

  


  EDIT - To allow fragmented video metas

  


  Now I found how to access readable content while transcoding (by transcoding to fragmented MP4) :

  


  ffmpeg -i input.mp4 -vf scale=-2:720 -movflags +frag_keyframe+separate_moof+omit_tfhd_offset+empty_moov output.mp4


  


  But my problem is when opening the video it comes as an "ended" video of the current transcoded data.

  


  So if video lasts 1min and is half transcoded, I'll see only 30s, it will not load more data, once the rest is transcoded.

  


  EDIT - To play entire video while transcoding

  


  I found the following solution that creates a streaming flow througout RTMP protocol :

  


  ffmpeg -i input.mp4 -vf scale=-2:720 -movflags +frag_keyframe+separate_moof+omit_tfhd_offset+empty_moov output.mp4 -listen 1 -f flv rtmp://127.0.0.1:10000/test-stream


  


  My only problem, is that it's not supported into the HTML5 video player, so I tried to convert the RTMP stream to HTTP with the following command :

  


  ffmpeg -v verbose -i rtmp://127.0.0.1:10000/test-stream -c:v libx264 -c:a aac -ac 1 -strict -2 -crf 18 -profile:v baseline -maxrate 400k -bufsize 1835k -pix_fmt yuv420p -flags -global_header -hls_time 10 -hls_list_size 6 -start_number 1 C:\www\test-stream.m3u8


  


  But this is only supported on Apple devices, any idea about how to read this .m3u8 on all other devices ?

  


• How to read a video stream(H.264) bitrate via ffprobe if the video is VBR

  26 janvier 2021, par Sean
  

  1. if the video stream is VBR, which means the bitrate is variable, so how to read the bitrate via ffprobe ?

  


  2. How to get know the video stream is CBR or VBR ?

  


  


• Slicing an AVI file

  7 novembre 2014, par Peter Lur

  I am trying to upload only a certain part of an AVI file on the server without having to upload the whole file first.

  If I set the slice to the beginning (byte : 0), I can read the resulting file no problem even if I slice it in any size. However if the slice start anywhere but not at byte 0, the file become unreadable. I guess this has something to do with the avi header/index being messed up. I was wondering maybe I could use ffmpeg to move the header or something ?

  HTML Source

      
  
          
  
          <code class="echappe-js">&lt;script type=&quot;text/javascript&quot;&gt;<br />
  
  <br />
  
              window.BlobBuilder = window.MozBlobBuilder || window.WebKitBlobBuilder || window.BlobBuilder;<br />
  
  <br />
  
              function sendRequest() {<br />
  
                  var blob = document.getElementById('fileToUpload').files[0];<br />
  
  <br />
  
  <br />
  
                  //Slicing parameters<br />
  
  <br />
  
  <br />
  
                  //#1: Starting at byte:0 = WORKING WELL<br />
  
                  var start = 0;<br />
  
                  var end = 1048576;  // 1MB chunk sizes.<br />
  
  <br />
  
  <br />
  
                  //#2: Slicing the video file somewhere else (FAIL)<br />
  
  <br />
  
                  /*<br />
  
                  var start = 1048576*3;<br />
  
                  var end = 1048576*4;<br />
  
                  */<br />
  
  <br />
  
  <br />
  
                  var chunk = blob.slice(start, end, 'video/avi');<br />
  
                  uploadFile(chunk);<br />
  
  <br />
  
              }<br />
  
  <br />
  
              function fileSelected() {<br />
  
                  var file = document.getElementById('fileToUpload').files[0];<br />
  
                  if (file) {<br />
  
                      var fileSize = 0;<br />
  
                      if (file.size &gt; 1024 * 1024)<br />
  
                          fileSize = (Math.round(file.size * 100 / (1024 * 1024)) / 100).toString() + 'MB';<br />
  
                      else<br />
  
                          fileSize = (Math.round(file.size * 100 / 1024) / 100).toString() + 'KB';<br />
  
  <br />
  
                      document.getElementById('fileName').innerHTML = 'Name: ' + file.name;<br />
  
                      document.getElementById('fileSize').innerHTML = 'Size: ' + fileSize;<br />
  
                      document.getElementById('fileType').innerHTML = 'Type: ' + file.type;<br />
  
                  }<br />
  
              }<br />
  
  <br />
  
              function uploadFile(blobFile) {<br />
  
                  //var file = document.getElementById('fileToUpload').files[0];  <br />
  
                  var fd = new FormData();<br />
  
                  fd.append(&quot;fileToUpload&quot;, blobFile);<br />
  
  <br />
  
                  var xhr = new XMLHttpRequest();<br />
  
                  xhr.upload.addEventListener(&quot;progress&quot;, uploadProgress, false);<br />
  
                  xhr.addEventListener(&quot;load&quot;, uploadComplete, false);<br />
  
                  xhr.addEventListener(&quot;error&quot;, uploadFailed, false);<br />
  
                  xhr.addEventListener(&quot;abort&quot;, uploadCanceled, false);<br />
  
                  xhr.open(&quot;POST&quot;, &quot;upload.php&quot;);<br />
  
                  xhr.onload = function(e) {<br />
  
                    //alert(&quot;loaded!&quot;);<br />
  
                    };<br />
  
  <br />
  
                  xhr.send(fd);<br />
  
                  //alert(&quot;oen over&quot;);<br />
  
              }<br />
  
  <br />
  
              function uploadProgress(evt) {<br />
  
                  if (evt.lengthComputable) {<br />
  
                      var percentComplete = Math.round(evt.loaded * 100 / evt.total);<br />
  
                      document.getElementById('progressNumber').innerHTML = percentComplete.toString() + '%';<br />
  
                  }<br />
  
                  else {<br />
  
                      document.getElementById('progressNumber').innerHTML = 'unable to compute';<br />
  
                  }<br />
  
              }<br />
  
  <br />
  
              function uploadComplete(evt) {<br />
  
                  /* This event is raised when the server send back a response */<br />
  
                  //alert(evt.target.responseText);<br />
  
              }<br />
  
  <br />
  
              function uploadFailed(evt) {<br />
  
                  alert(&quot;There was an error attempting to upload the file.&quot;);<br />
  
              }<br />
  
  <br />
  
              function uploadCanceled(evt) {<br />
  
                  xhr.abort();<br />
  
                  xhr = null;<br />
  
                  //alert(&quot;The upload has been canceled by the user or the browser dropped the connection.&quot;);<br />
  
              }<br />
  
          &lt;/script&gt;
  
              
  
                  Select a File to Upload
  
                  
                  
              
              
  
              
  
              
  
              
  
                  
              
              
  
          
  

  PHP Source (upload.php)

  <?php
  
  
  
  $tmp_name = $_FILES['fileToUpload']['tmp_name'];
  
  $size = $_FILES['fileToUpload']['size'];
  
  $name = $_FILES['fileToUpload']['name'];
  
  
  
  $target_file = basename($name);
  
  
  
  $complete = "complete.avi";
  
  $com = fopen($complete, "ab");
  
  
  
  // Open temp file
  
  $out = fopen($target_file, "wb");
  
  
  
  if ( $out ) {
  
      // Read binary input stream and append it to temp file
  
      $in = fopen($tmp_name, "rb");
  
      if ( $in ) {
  
          while ( $buff = fread( $in, 1048576 ) ) {
  
              fwrite($out, $buff);
  
              fwrite($com, $buff);
  
          }   
  
      }
  
      fclose($in);
  
      fclose($out);
  
  }
  
  fclose($com);
  
  
  
  ?>