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• Speeding Up H.264 Frame Loader

  9 avril 2021, par user14607943

  I have a set of videos, that are about 15 seconds each, in H.264 format. I'm currently using skvideo.io.vread to ingest and process these. Specifically, I'm looking to extract x frames per second, where for example x=1. Current, I have :

  


  import skvideo
gen = skvideo.io.vreader('video.mp4', outputdict={'-r':'1'})

for f in gen:
   "do stuff with frames"


  


  I'm running a Python Flask service with multiple workers, which accepts requests with video inputs. Unfortunately, due to high QPS, I'm having super high CPU usage, and I was hoping to find a faster way of ingesting the frames from these videos.

  


  


  1. Can the above code be optimized in any way to speed up the frame extraction. I think FFMPEG is already subsampling the frames upon loading, but I'm not entirely sure. I'm willing to compromise on the exact logic of how the frames are extracted, so long as I'm roughly getting 1-2 frames per second of video. I saw this question, and am actively exploring whether the CPU optimizations are enabled for FFMPEG.

     


  


  2. Is there an alternative to skvideo that can potentially be faster, and possibly work better in my service ?

     


  


  


• "Transcode" copying video/audio codec

  22 septembre 2012, par JunCTionS

  I took some very shaky video, and went online to try and find how to stabilize it. I came upon this nice blog that uses transcode for it.
  Following the blog instructions it worked very nice, but the end result had a lot of compression artifacts. This I imagine is mostly due to using xvid as a new codec.

  My intention is reuse the codec the camera originally used which is H.264/AVC but I haven't found a way of doing so (ran into various dead ends using either encoder -y mov... or -y ffpmeg.

  In particular when using -y ffmpeg -F "-vcodec copy -acodec copy" it prints out :

  [export_ffmpeg.so] warning: Video template standard must be one of pal/ntsc

  but running

  ffmpeg -i input.mov -vcodec copy -acodec copy output.mov

  Presents no problem.

  Any idea on how to do this ? or an alternative to stabilize video on linux ?.

• What are the different ways to generate thumbnail of video in PHP ? [on hold]

  10 février 2016, par Vaidehi

  Is there any alternative for FFMPEG to get Video thumbnails in PHP ?
  Client don’t want to use EXEC and other server commands due to security issues.
  FFMPEG library need EXEC() to be enabled. So I am looking for other alternatives.
  I am using below code to generate thumbnail of video using PHP. But on server exec() function is disabled due to security reasons. So, I can’t use FFMPEG to generate thumbnail.

  ----------------------------
  
  $thumbnail_path = "your_site_domain/media/images/thumbnail/"; 
  
  $second = 1;
  
  $thumbSize="150x150"; 
  
  $videoname="sample_video";
  
  
  
  $cmd="{$ffmpeg_installation_path} -i {$video_file_path} -deinterlace -an -ss {$second} -t 00:00:01  -s {$thumbSize} -r 1 -y -vcodec mjpeg -f mjpeg {$path_to_store_generated_thumbnail} 2>&1";
  
  exec($cmd, $output, $retval);
  
  if ($retval)
  
  {
  
      echo "error in generating video thumbnail";
  
  }
  
  else
  
  {
  
      echo "Thumbnail generated successfully";
  
      echo $thumb_path=$thumbnail_path.$videoname.".jpg";
  
  }
  
  -------------------------------

  In my case, video can be of any format like .mp4, .avi, youtube link or any possible video which I am going to upload using php and while uploading I want to generate thumbnail of same. If any solution then please reply me back.