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• avcodec/rkmppdec : Fix double-free on error

  24 septembre 2023, par Andreas Rheinhardt

  avcodec/rkmppdec : Fix double-free on error
  After having created the AVBuffer that is put into frame->buf[0],
  
  ownership of several objects (namely an AVDRMFrameDescriptor,
  
  an MppFrame and some AVBufferRefs framecontextref and decoder_ref)
  
  has passed to the AVBuffer and therefore to the frame.
  
  Yet it has nevertheless been freed manually on error
  
  afterwards, which would lead to a double-free as soon
  
  as the AVFrame is unreferenced.
  Signed-off-by : Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
  

  • [DH] libavcodec/rkmppdec.c

• avcodec/mips/aaccoder_mips : Remove MIPS-specific aaccoder

  15 mars 2024, par Andreas Rheinhardt

  avcodec/mips/aaccoder_mips : Remove MIPS-specific aaccoder
  ff_aac_coder_init_mips() modifies a static const structure of
  
  function pointers. This will crash if the binary uses relro
  
  and is a data race in any case.
  Furthermore it points to a maintainability issue : The
  
  AACCoefficientsEncoder structures have been constified
  
  in commit fd9212f2edfe9b107c3c08ba2df5fd2cba5ab9e3,
  
  a Libav commit merged in 318778de9ebec276cb9dfc65509231ca56590d13.
  
  Libav did not have the MIPS-specific AAC code and so this was
  
  fine for them ; yet FFmpeg had them, but this was not recognized.
  Commit 75a099fc734a4ee2b1347d0a3d8c53d883b95174 points to another
  
  maintainability issue : Contrary to ordinary DSP code, this code
  
  here is way more complex and needs to be constantly kept in sync
  
  with the ordinary code which it mimicks and replaces. Said commit
  
  is the only commit actually changing aaccoder.c in the last few
  
  years and the same change has not been performed for the MIPS
  
  clone ; before that, it even happened several times that the mips
  
  code was broken due to changes of the generic code (see commits
  
  97437bd17a8c5d4135b2f3b1b299bd7bb72ce02c and
  
  de262d018d7d7d9c967af1dfd1b861c4b9eb2a60 or
  
  860dbe0275e57cbf4228f3f653f872ff66ca596b or
  
  933309a6ca0f18bf1d40e917fff455221f57fb4b or
  
  b65ffa316e377213c29736929beba584d0d80d7c). This might even lead
  
  to scenarios where someone changing non-dsp aacenc code would
  
  have to modify mips inline asm in order to keep them in sync.
  
  This is obviously a significant burden (if the AAC encoder were
  
  actively developed).
  Finally, the code does not even compile here due to errors like
  
  "Error : float register should be even, was 1".
  Reviewed-by : Lynne <dev@lynne.ee>
  
  Reviewed-by : Jean-Baptiste Kempf <jb@videolan.org>
  
  Signed-off-by : Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
  

  • [DH] libavcodec/aacenc.c
  • [DH] libavcodec/aacenc.h
  • [DH] libavcodec/mips/Makefile
  • [DH] libavcodec/mips/aaccoder_mips.c

• ffmpeg : set extra_hw_frames to account for frames held in queues

  25 février 2024, par Mark Thompson

  ffmpeg : set extra_hw_frames to account for frames held in queues
  Since e0da916b8f5b079a4865eef7f64863f50785463d the ffmpeg utility has
  
  held multiple frames output by the decoder in internal queues without
  
  telling the decoder that it is going to do so.  When the decoder has a
  
  fixed-size pool of frames (common in some hardware APIs where the output
  
  frames must be stored as an array texture) this could lead to the pool
  
  being exhausted and the decoder getting stuck.  Fix this by telling the
  
  decoder to allocate additional frames according to the queue size.
  

  • [DH] fftools/ffmpeg_dec.c
  • [DH] fftools/ffmpeg_sched.c
  • [DH] fftools/ffmpeg_sched.h