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• avcodec/tiff : Restrict tag order based on specification

  20 août 2020, par Michael Niedermayer

  avcodec/tiff : Restrict tag order based on specification
  "The entries in an IFD must be sorted in ascending order by Tag. Note that this is
  
   not the order in which the fields are described in this document."
  This way various dimensions, sample and bit sizes cannot be changed at
  
  arbitrary times which reduces the potential for bugs.
  
  The tag reading code also on various places assumes that numerically previous
  
  tags have already been parsed, so this needs to be enforced one way or another.
  If this commit causes problems with real world files which are not easy to fix
  
  then some other form of checks are needed to ensure the various dependencies
  
  in the tag reading are not violated.
  Fixes : out of array access
  
  Fixes : 24825/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_TIFF_fuzzer-6326925027704832
  Found-by : continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
  
  Signed-off-by : Michael Niedermayer <michael@niedermayer.cc>
  

  • [DH] libavcodec/tiff.c

• avcodec/celp_math : avoid overflow in shift

  7 septembre 2023, par Michael Niedermayer

  avcodec/celp_math : avoid overflow in shift
  by making gain unsigned we have 1 bit more available
  
  alternatively we can clip twice as in the g729 reference
  Fixes : left shift of 23404 by 17 places cannot be represented in type 'int'
  
  Fixes : 61728/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_ACELP_KELVIN_fuzzer-6280412547383296
  Found-by : continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
  
  Signed-off-by : Michael Niedermayer <michael@niedermayer.cc>
  

  • [DH] libavcodec/celp_math.h
  • [DH] libavcodec/g729postfilter.c

• ffmpeg : How to get list of available codecs with PHP ?

  9 août 2013, par IIIOXIII

  Problem is, I am trying to convert (through php), a .3gp (or any video format) file to ogg.

  When I do not specify -vcodec and -acodec, the video is converted, but does not have any audio.

  I had read here and other places that I need to specify -acodec libvorbis, however, when I specify the codec as libvorbis, the conversion fails : video converts to 0byte file.

  Basically, I am trying to determine if the codec specified is actually part of the ffmpeg build I am using as a process of narrowing down my issue.

  Code that produces full length video without sound :

  $srcFile = 'anyvideo.3gp';
  
  $destFile = 'anyvideo.ogg';
  
  $ffmpegPath = 'path/to/ffmpeg.exe';
  
  $ffmpegObj = new ffmpeg_movie($srcFile);
  
  $srcWidth = makeMultipleTwo($ffmpegObj->getFrameWidth()); 
  
  $srcHeight = makeMultipleTwo($ffmpegObj->getFrameHeight());
  
  $srcFPS = $ffmpegObj->getFrameRate(); 
  
  $srcAB = intval($ffmpegObj->getAudioBitRate()/1000);
  
  $srcAR = $ffmpegObj->getAudioSampleRate();
  
  $srcLen = $ffmpegObj->getDuration();
  
  
  
  exec($ffmpegPath." -i ".$srcFile." -ar ".$srcAR." -s ".$srcWidth."x".$srcHeight." ". $destFile);

  And the code that produces 0byte file :

  exec($ffmpegPath." -i ".$srcFile." -acodec libvorbis -ar ".$srcAR." -s ".$srcWidth."x".$srcHeight." ".$destFile);

  So, my question is, how do I determine the codec's available to ffmpeg using PHP ? Can it even be done ?

  UPDATED - ANSWER BELOW