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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.

• avformat/oggenc : Avoid allocating and copying when writing page data

  3 mai 2020, par Andreas Rheinhardt

  avformat/oggenc : Avoid allocating and copying when writing page data
  When the Ogg muxer writes a page, it has to do three things : It needs to
  
  write a page header, then it has to actually copy the page data and then
  
  it has to calculate and write a CRC checksum of both header as well as
  
  data at a certain position in the page header.
  To do this, the muxer used a dynamic buffer for both writing as well as
  
  calculating the checksum via an AVIOContext's feature to automatically
  
  calculate checksums on the data it writes. This entails an allocation of
  
  an AVIOContext, of the opaque specific to dynamic buffers and of the
  
  buffer itself (which may be reallocated multiple times) as well as
  
  memcopying the data (first into the AVIOContext's small write buffer,
  
  then into the dynamic buffer's big buffer).
  This commit changes this : The page header is no longer written into a
  
  dynamic buffer any more ; instead the (small) page header is written into
  
  a small buffer on the stack. The CRC is then calculated directly via
  
  av_crc() on both the page header as well as the page data. Then both the
  
  page header and the page data are written.
  Finally, ogg_write_page() can now no longer fail, so it has been
  
  modified to return nothing ; this also fixed a bug in the only caller of
  
  this function : It didn't check the return value.
  Signed-off-by : Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
  

  • [DH] libavformat/oggenc.c