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• Lossless trim and crop of MJPEG video

  28 avril 2021, par prouast

  I am working on a project where I need to trim and crop MJPEG videos without any re-encoding. I have working code that accomplishes this by exporting the relevant frames as JPEGs, cropping them individually, and then joining them back together into an MJPEG.

  


  However, this seems quite inefficient and slow. I am looking for pointers how to improve this approach. For example, would it be possible to store the JPEGs in-memory ?

  


  import ffmpeg
import os
import shutil
import subprocess

def lossless_trim_and_crop(path, output_path, start, end, x, y, width, height, fps):
  # Trim the video in time and export all individual jpeg with ffmpeg + mjpeg2jpeg
  jpeg_folder = os.path.splitext(output_path)[0]
  jpeg_path = os.path.join(jpeg_folder, "frame_%03d.jpg")
  stream = ffmpeg.input(path, ss=start/fps, t=(end-start)/fps)
  stream = ffmpeg.output(stream, jpeg_path, vcodec='copy', **{'bsf:v': 'mjpeg2jpeg'})
  stream.run(quiet=True)
  # Crop all individual jpeg with jpegtran
  for filename in os.listdir(jpeg_folder):
    filepath = os.path.join(jpeg_folder, filename)
    out_filepath = os.path.splitext(filepath)[0] + "_c.jpg"
    subprocess.call(
      "jpegtran -perfect -crop {}x{}+{}+{} -outfile {} {}".format(
        width, height, x, y, out_filepath, filepath), shell=True)
    os.remove(filepath)
  # Join individual jpg back together
  cropped_jpeg_path = os.path.join(jpeg_folder, "frame_%03d_c.jpg")
  stream = ffmpeg.input(cropped_jpeg_path, framerate=fps)
  stream = ffmpeg.output(stream, output_path, vcodec='copy')
  stream.run(quiet=True)
  # Delete jpeg directory
  shutil.rmtree(jpeg_folder)


  


• AE per frame rendering FFMPEG forming to video

  9 février 2018, par Deckard Cain

  I’m trying to setup an automated per frame rendering system using After Effects and FFMPEG. The idea here is that my slave nodes (running AE), will generate the frames and save them immediately to a Samba share (this way I can team multiple slaves together to tackle the same project file and we aren’t writing an 8GB AVI file, then compressing and deleting it when we could just render 300MB of frames and form it).

  The database and Samba share are running on FreeBSD. This machine will then take those frames and use FFMPEG to combine them into an MP4 video.

  The issue that I’m running into, is that when I render out the After Effects project file directly to an AVI file (one slave, no individual frame rendering), the video length is 1:31. When I render out the exact same project file into individual frames, then run it through FFMPEG to combine and compress them, the output is 1:49.

  I have tried a billion different things to make the length of the video the same, but can’t seem to make it so :/

  aerender.exe -mp -project %PROJECTFILE% -comp %COMPOSITION% -output [########].jpg

  ^Keep in mind, there may be 99999999 frames, or as little as 1 that needs to be rendered (if we need to re-render a specific section because of an asset change)

  ffmpeg -nostdin -i %FRAMELOCATION% -c:v libx264 -preset veryfast -an -y outputVideo.mp4

• WebM file not seekable in Chrome when loaded through PHP (other browsers work)

  13 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 !