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• Python Lambda function and ffmpeg command with stdout from jpg to ts file

  28 juillet 2021, par Sflagg

  I have a AWS Lambda Python function setup to process jpg and convert it to a ts file.

  


  I followed these instructions https://aws.amazon.com/blogs/media/processing-user-generated-content-using-aws-lambda-and-ffmpeg/ but changed the command from vfr to cfr conversion to a jpg to ts conversion.

  


  This is the command I am using

  


  ffmpeg_cmd = "/opt/bin/ffmpeg -r 30000/1001 -loop 1 -i \"" + s3_source_signed_url + "\" -f lavfi -i anullsrc=channel_layout=stereo:sample_rate=48000 -t 30 -vcodec libx264 -crf 23 -s 1920x1080 -r 30000/1001 -g 150 -pix_fmt yuv420p -acodec aac -b:a 96k -ar 48000 -"

  


  Everything else is basically the same from the AWS article besides having s3 triggers in my Lambda look for jpeg and jpg suffixes.

  


  But this results in 0 byte ts file.

  


  I have a hunch that I need to modify the command that has a seekable output format (e.g. mpegts) when writing to stdout ; currently my command is likely not working for stdout and that is why I get an empty ts file. But I am having trouble formatting the command correctly. Any help with this would be greatly appreciated !

  


• Creating Thumbnails From Ffmpeg Hangs Php

  30 octobre 2012, par Piyush Arora

  I have been working on a php webservice, which receives videos(uploaded) from iphone and upload them to Amazon cloudFront. After uploading videos, I need to generate thumbnails for video from the Amazon link generated. I am using ffmpeg with shell_exec command for it. Here is the code for the same :

  public function createThumbnail($userId,$fileUrl,$imageName){
  
      //$imageUrl = 'http://184.168.116.177:81/json_api/json/bin/';
  
      if(!is_dir("images/".$userId)){
  
          mkdir("images/".$userId);
  
      }
  
      // path of installed ffmpeg
  
      $ffmpeg = $_SERVER['DOCUMENT_ROOT'] .'bin/ffmpeg';
  
      $cmd = "$ffmpeg  -itsoffset -1 -i $fileUrl -vcodec mjpeg -vframes 1 -an -f rawvideo -s 320x240 images/".$userId."/".$imageName;
  
  
  
      shell_exec($cmd);
  
  
  
      return "images/".$userId."/".$imageName;
  
  }

  The above code generates the thumbnail, but script does not execute after shell_exec command. So, there is no response sent to iphone end about the thumbnail link. This function works well video is uploaded from web browser of pc. If I comment, shell_exec command, then response is sent to iphone end, but obviousely image is not created.

  Thanks in advance.

• ffmpeg screencasting with webcam

  6 septembre 2017, par curiouser

  I want to use the screen view of the computer in real-time for a fake webcam. I did the video action on the bottom. But the frames like the video (2.34) are forming on top of each other. How can I solve this problem.

  https://www.youtube.com/watch?v=6AZRiW3hHrw

  Load the module
  
  sudo modprobe v4l2loopback exclusive_caps=1
  
  
  
  Find the dummy device
  
  v4l2-ctl --list-devices
  
  
  
  Start the virtual-webcam (change "/dev/video1" to reflect your system)
  
  ffmpeg -f x11grab -r 15 -s 1920x1080 -i :0.0+0,0 -vcodec rawvideo -pix_fmt yuv420p -threads 0 -f v4l2 /dev/video1