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• FFmpeg upmix command stereo > 5.1

  2 octobre 2018, par CupNoodleFanatic

  I need to upmix stereo mkv files with chapter, subtitle, audio and video streams to 5.1 flac with a silent center channel. The audio is a single stereo stream, not two mono streams. I need the resulting mkv to contain a single 6 channel flac stream.

  My desired channel layout is FR = FR, FR > SR, FL = FL, FL > SL, Center silent, LFE = FR+FL

  I followed the FFmpeg documentation and was unable to produce the desired mapping.

  The command so far (generated with help from Axiom GUI) :

  ./ffmpeg -i TestIN.mkv -c:v copy -map 0:v? -map_chapters 0 -c:s copy -map 0:s? -c:a flac -sample_fmt s16 -rematrix_maxval 1.0 -ac 6 -map 0:a:0? -map_metadata 0 -f matroska -threads 0 X:\TestOUT.mkv

  Any help would be greatly appreciated.

• avcodec/mpeg12dec : Don't adapt (last|next)_pic.linesize for field pics

  23 juin 2024, par Andreas Rheinhardt

  avcodec/mpeg12dec : Don't adapt (last|next)_pic.linesize for field pics
  These values are not read anywhere. Furthermore, since commit
  
  fe6037fd04db8837dcdb9013f9c4ad4e7eb0592e the linesize values
  
  of the MPVWorkPictures were wrong for subsequent fields
  
  in a chain of B-pictures (as they are always doubled and no longer
  
  based upon the frame-linesizes) which can eventually lead to overflow.
  Finally, it makes no real sense to ever double the linesize
  
  of the reference pictures at all : Even when the current picture
  
  is a field, it can still reference both fields of reference
  
  pictures and therefore the linesize should allow to address
  
  both fields (for the same reason, data is not offset for
  
  reference pictures).
  libavcodec/mpeg12dec.c:1304:41 : runtime error : signed integer overflow : 4611686018427387904 * 2 cannot be represented in type 'long'
  issue : 69732/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_MPEGVIDEO_fuzzer-5123551179374592
  Reviewed-by : Michael Niedermayer <michael@niedermayer.cc>
  
  Signed-off-by : Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
  

  • [DH] libavcodec/mpeg12dec.c

• Converting a video and capturing a thumbnail through ffmpeg-php

  14 mai 2014, par HackerManiac

  Can anyone give a code on how do i upload and covert a video using ffmpeg.

  As thought currently i have only uploading system.

  vu.php

  define('UPLOAD','../../videos/');
  
      $fileName = time().$file['name']; 
  
      $target = UPLOAD.$fileName;
  
  
  
    if(move_uploaded_file($file['tmp_name'],$target)){                
  
        exec("ffmpeg -i ".UPLOAD." ".UPLOAD.$filename.".flv"); 
  
    }

  This pice of code block just uploads the video on video folder but does not converts it to .flv.
  I am not sure how to use ffmpeg.

  My diretory looks like this

  www[localhost]->videos[videos folder]
  
  www[localhost]->pictures[pictures folder]
  
  www[localhost]->resources[folder]->php[folder]->vu.php

  I also want to return a .jpg image of any frame of video through json by converting via ffmpeg and uploading it to pictures folder.

  return json_encode(array("thumbnail"=>$image_src));