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• WebM file not seekable in Chrome, when generated with ffmpeg

  11 avril 2014, par Zoon

  I am having a mind-boggling problem, I just can't seem to resolve.

  Providing a WebM file through PHP is nothing new in my world, and I even know how to work with HTTP 206 Partial Content. But for some reason Chrome does not like it.

  A simple HTML5 video playback

  <video width="640" height="360" poster="picture/preview/V00000006.jpg" controls="controls" preload="preload">
  
      <source type="video/webm" src="/video/V00000006.webm">
  
  </source></video>

  where /video/V00000006.webm is rewritten to a PHP-file in Apache, will playback just fine.
  But in Chrome the seekbar is not effective. When clicking on the seekbar the player will freeze and no longer playback until page is refreshed. Firefox handles it just fine !

  If I change /video/V00000006.webm to be a direct link to the same video it works just fine. I even compared the network requests between the two versions (with and without PHP) and there is barely any difference in the first request, but the second is failing in the PHP-delivered video.

  Initial request and seek request for Apache-delivered video file :

      Request URL :http://mytestserver.net/movie1152x720.webm
      Request Method:GET
      Status Code:206 Partial Content
      Request Headers
      Accept :*/*
      Accept-Encoding:identity ;q=1, * ;q=0
      Accept-Language:da-DK,da ;q=0.8,en-US ;q=0.6,en ;q=0.4
      Cache-Control:no-cache
      Connection:keep-alive
      Cookie:PHPSESSID=i562540rek172mnv3nk528acj0 ; userPassword= ; userEmail=
      Host:mytestserver.net
      Pragma:no-cache
      Range:bytes=0-
      Referer :http://mytestserver.net/video.html
      User-Agent:Mozilla/5.0 (X11 ; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/33.0.1750.146 Safari/537.36
      Response Headers
      Accept-Ranges:bytes
      Connection:close
      Content-Length:4446451
      Content-Range:bytes 0-4446450/4446451
      Content-Type:video/webm
      Date:Fri, 11 Apr 2014 13:07:30 GMT
      ETag :"d2d0027-43d8f3-b91417c0"
      Last-Modified:Fri, 11 Apr 2014 12:46:31 GMT
      Server:Apache/2.2.3 (CentOS)
      —
      Request URL :http://mytestserver.net/movie1152x720.webm
  
      Request Method:GET
  
      Status Code:206 Partial Content
  
      Request Headers
  
      Accept :*/*
  
      Accept-Encoding:identity ;q=1, * ;q=0
  
      Accept-Language:da-DK,da ;q=0.8,en-US ;q=0.6,en ;q=0.4
  
      Cache-Control:no-cache
  
      Connection:keep-alive
  
      Cookie:PHPSESSID=i562540rek172mnv3nk528acj0 ; userPassword= ; userEmail=
  
      Host:mytestserver.net
  
      Pragma:no-cache
  
      Range:bytes=4445881-
  
      Referer :http://mytestserver.net/video.html
  
      User-Agent:Mozilla/5.0 (X11 ; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/33.0.1750.146 Safari/537.36
  
      Response Headers
  
      Accept-Ranges:bytes
  
      Connection:close
  
      Content-Length:570
  
      Content-Range:bytes 4445881-4446450/4446451
  
      Content-Type:video/webm
  
      Date:Fri, 11 Apr 2014 13:09:02 GMT
  
      ETag :"d2d0027-43d8f3-b91417c0"
  
      Last-Modified:Fri, 11 Apr 2014 12:46:31 GMT
  
      Server:Apache/2.2.3 (CentOS)
  

  Initial request and seek request for PHP-streamed video :

      Request URL :http://mytestserver.net/video/V00000006.webm
      Request Method:GET
      Status Code:206 Partial Content
      Request Headers
      Accept :*/*
      Accept-Encoding:identity ;q=1, * ;q=0
      Accept-Language:da-DK,da ;q=0.8,en-US ;q=0.6,en ;q=0.4
      Cache-Control:no-cache
      Connection:keep-alive
      Cookie:PHPSESSID=i562540rek172mnv3nk528acj0 ; userPassword= ; userEmail=
      Host:mytestserver.net
      Pragma:no-cache
      Range:bytes=0-
      Referer :http://mytestserver.net/video.html
      User-Agent:Mozilla/5.0 (X11 ; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/33.0.1750.146 Safari/537.36
      Response Headers
      Accept-Ranges:bytes
      Cache-Control:no-store, no-cache, must-revalidate, post-check=0, pre-check=0
      Connection:close
      Content-Length:8566268
      Content-Range:bytes 0-8566267/8566268
      Content-Type:video/webm
      Date:Fri, 11 Apr 2014 13:31:27 GMT
      Expires:Thu, 19 Nov 1981 08:52:00 GMT
      Pragma:no-cache
      Server:Apache/2.2.3 (CentOS)
      X-Powered-By:PHP/5.3.27
      —
      Request URL :http://mytestserver.net/video/V00000006.webm
  
      Request Headers CAUTION : Provisional headers are shown.
  
      Accept-Encoding:identity ;q=1, * ;q=0
  
      Cache-Control:no-cache
  
      Pragma:no-cache
  
      Range:bytes=4338314-
  
      Referer :http://mytestserver.net/video.html
  
      User-Agent:Mozilla/5.0 (X11 ; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/33.0.1750.146 Safari/537.36
  

  Notice how the second request does not complete, Provisional headers are shown.

  I have tried altering the cache headers, setting it to the future, setting them blank and using file attachment headers.

  I tried fiddling around a lot with the serving code, but lately I have ended up with a simple example.

  <?php
  
  
  
  $path = 'test.webm';
  
  
  
  $size=filesize($path);
  
  
  
  $fm=@fopen($path,'rb');
  
  if(!$fm) {
  
    header ("HTTP/1.0 404 Not Found");
  
    die();
  
  }
  
  
  
  $begin=0;
  
  $end = $size-1;
  
  
  
  if(isset($_SERVER['HTTP_RANGE'])) {
  
    if(preg_match('/bytes=\h*(\d+)-(\d*)[\D.*]?/i', $_SERVER['HTTP_RANGE'], $matches)) {
  
      $begin=intval($matches[0]);
  
      if(!empty($matches[1])) {
  
        $end=intval($matches[1]);
  
      }
  
    }
  
  }
  
  
  
  if($begin>0||$end<$size)
  
    header('HTTP/1.0 206 Partial Content');
  
  else
  
    header('HTTP/1.0 200 OK');
  
  
  
  header("Content-Type: video/webm");
  
  header('Accept-Ranges: bytes');
  
  header('Content-Length:'.($end-$begin+1));
  
  header("Content-Disposition: inline;");
  
  header("Content-Range: bytes $begin-$end/$size");
  
  header("Content-Transfer-Encoding: binary\n");
  
  header('Connection: close');
  
  
  
  ob_get_clean();
  
  flush();
  
  
  
  $f = fopen($path, 'r');
  
  fseek($f, $offset);
  
  
  
  $pos = 0;
  
  $length = $end-$begin;
  
  
  
  while($pos < $length)
  
  {
  
      $chunk = min($length-$pos, 1024);
  
  
  
      echo fread($f, $chunk);
  
      flush();
  
  
  
      $pos += $chunk;
  
  }
  
  ?>

  Please note, entering the PHP-delivered video URL directly into the browser does not make a difference from showing it in a HTML page.

  I hope someone has an answer to why seeking might not work. Let me know if you have any suggestions.

  Thanks !

• How to pipe live video frames from ffmpeg to PIL ?

  30 janvier 2017, par Ryan Martin

  I need to use ffmpeg/avconv to pipe jpg frames to a python PIL (Pillow) Image object, using gst as an intermediary*. I’ve been searching everywhere for this answer without much luck. I think I’m close - but I’m stuck. Using Python 2.7

  My ideal pipeline, launched from python, looks like this :

  1. ffmpeg/avconv (as h264 video)
  2. Piped ->
  3. gst-streamer (frames split into jpg)
  4. Piped ->
  5. Pil Image Object

  I have the first few steps under control as a single command that writes .jpgs to disk as furiously fast as the hardware will allow.

  That command looks something like this :

  command = [
  
          "ffmpeg",
  
          "-f video4linux2",
  
          "-r 30",
  
          "-video_size 1280x720",
  
          "-pixel_format 'uyvy422'",
  
          "-i /dev/video0",
  
          "-vf fps=30",
  
          "-f H264",
  
          "-vcodec libx264",
  
          "-preset ultrafast",
  
          "pipe:1 -",
  
          "|", # Pipe to GST
  
          "gst-launch-1.0 fdsrc !",
  
          "video/x-h264,framerate=30/1,stream-format=byte-stream !",
  
          "decodebin ! videorate ! video/x-raw,framerate=30/1 !",
  
          "videoconvert !",
  
          "jpegenc quality=55 !",
  
          "multifilesink location=" + Utils.live_sync_path + "live_%04d.jpg"
  
        ]

  This will successfully write frames to disk if ran with popen or os.system.

  But instead of writing frames to disk, I want to capture the output in my subprocess pipe and read the frames, as they are written, in a file-like buffer that can then be read by PIL.

  Something like this :

      import subprocess as sp
  
      import shlex
  
      import StringIO
  
  
  
      clean_cmd = shlex.split(" ".join(command))
  
      pipe = sp.Popen(clean_cmd, stdout = sp.PIPE, bufsize=10**8)
  
  
  
      while pipe:
  
  
  
          raw = pipe.stdout.read()
  
          buff = StringIO.StringIO()
  
          buff.write(raw)
  
          buff.seek(0)
  
  
  
          # Open or do something clever...
  
          im = Image.open(buff)
  
          im.show()
  
  
  
          pipe.flush()

  This code doesn’t work - I’m not even sure I can use "while pipe" in this way. I’m fairly new to using buffers and piping in this way.

  I’m not sure how I would know that an image has been written to the pipe or when to read the ’next’ image.

  Any help would be greatly appreciated in understanding how to read the images from a pipe rather than to disk.

  • This is ultimately a Raspberry Pi 3 pipeline and in order to increase my frame rates I can’t (A) read/write to/from disk or (B) use a frame by frame capture method - as opposed to running H246 video directly from the camera chip.

• using ffmpeg to capture the screen why it's not saving the output file to the folder and not saving the output file at all ?

  17 juillet 2023, par Shelly Ron

  at the top

  


  private bool recordFullScreen = true;
private Process ffmpegProcess;


  


  Load event

  


  private void Form1_Load(object sender, EventArgs e)
        {
            // Hide the FFmpeg console window
            var ffmpegStartInfo = new ProcessStartInfo
            {
                FileName = @"D:\Captured Videos\ffmpeg.exe",
                Arguments = "-hide_banner -loglevel panic",
                UseShellExecute = false,
                CreateNoWindow = true,
                RedirectStandardInput = true
            };

            ffmpegProcess = Process.Start(ffmpegStartInfo);
        }


  


  Closing event

  


  private void Form1_FormClosing(object sender, FormClosingEventArgs e)
        {
            // Terminate FFmpeg process before closing the application
            ffmpegProcess.StandardInput.WriteLine("q");
            ffmpegProcess.WaitForExit();
            ffmpegProcess.Close();
        }


  


  recording button click event

  


  private void btnRecord_Click(object sender, EventArgs e)
        {
            if (recordFullScreen)
            {
                // Record the whole screen
                RecordScreen();
            }
        }


  


  the method recordscreen

  


  private void RecordScreen()
        {
            // Set the output folder path
            string outputFolder = @"D:\Captured Videos\";

            // Generate a unique file name based on the current date and time
            string fileName = DateTime.Now.ToString("Screen_yyyyMMdd_HHmmss") + ".mp4";

            // Set the output file path
            string outputFile = Path.Combine(outputFolder, fileName);

            // FFmpeg command to record the whole screen
            string ffmpegCommand = $"-f gdigrab -framerate 24 -i desktop -preset ultrafast -pix_fmt yuv420p \"{outputFile}\"";

            StartFFmpeg(ffmpegCommand);
        }


  


  the method startffmpeg

  


  private void StartFFmpeg(string command)
        {
            // Send the FFmpeg command to the process for execution
            ffmpegProcess.StandardInput.WriteLine(command);
            ffmpegProcess.StandardInput.Flush();
        }


  


  but when running the application pressing the button to record after some seconds i click the form red X on the top right to close it but it's not saving the mp4 output file. not sure if it's even recording at all.