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• avfilter/af_channelmap : Fix double-free of AVFilterChannelLayouts on error

  7 août 2020, par Andreas Rheinhardt

  avfilter/af_channelmap : Fix double-free of AVFilterChannelLayouts on error
  The query_formats function of the channelmap filter tries to allocate
  
  a list of channel layouts which on success are attached to more permanent
  
  objects (an AVFilterLink) for storage afterwards. If attaching succeeds,
  
  the link becomes one of the common owners (in this case, the only owner)
  
  of the list. Yet if the list has been successfully attached to the link
  
  and an error happens lateron, the list was manually freed, which is wrong,
  
  because it is owned by its link so that the link's pointer to the list will
  
  become dangling and there will be a double-free/use-after-free when the link
  
  is later cleaned up automatically.
  This commit fixes this by removing the custom freeing code ; this will
  
  temporarily add a leaking codepath (if attaching the list fails, the list
  
  will leak), but this will be fixed soon by making sure that an
  
  AVFilterChannelLayouts without owner will be automatically freed when
  
  attaching it to an AVFilterLink fails.
  Reviewed-by : Nicolas George <george@nsup.org>
  
  Signed-off-by : Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
  

  • [DH] libavfilter/af_channelmap.c

• How to build ffmpeg with hardware decoding support for raspberry pi ? (cross compilation if possible)

  29 avril 2022, par PPP

  Is it possible to build ffmpeg with decoding support for Raspberry Pi ? I've read that mmal can do hardware accelerated decoding on the Raspberry Pi.

  


  I've tried on debian 10 x86_64 :

  


  ./configure \
    --prefix=${BUILD_DIR}/desktop/${FFMPEG_ARCH_FLAG} \
    --disable-doc \
    --enable-cross-compile \
    --cross-prefix=${CROSS_PREFIX} \
    --target-os=linux \
    --arch=${FFMPEG_ARCH_FLAG} \
    --extra-cflags="-O3 -fPIC $EXTRA_CFLAGS" \
    --enable-mmal \
    --enable-omx \
    --enable-omx-rpi \
    --enable-shared \
    --disable-debug \
    --disable-runtime-cpudetect \
    --disable-programs \
    --disable-muxers \
    --disable-encoders \
    --disable-bsfs \
    --disable-pthreads \
    --disable-avdevice \
    --disable-network \
    --disable-postproc 


  


  where CROSS_PREFIX=aarch64-linux-gnu- and FFMPEG_ARCH_FLAG=aarch64 but obviously I get ERROR: mmal not found. I couldn't find MMAL to compile and install.

  


• avcodec/v4l2_m2m_dec : remove redundant packet and fix double free

  16 juillet 2020, par Andriy Gelman

  avcodec/v4l2_m2m_dec : remove redundant packet and fix double free
  v4l2_receive_frame() uses two packets s->buf_pkt and avpkt. If avpkt
  
  cannot be enqueued, the packet is buffered in s->buf_pkt and enqueued in
  
  the next call. Currently the ownership transfer between the two packets
  
  is not properly handled. A double free occurs if
  
  ff_v4l2_context_enqueue_packet() returns EAGAIN and v4l2_try_start
  
  returns EINVAL.
  In fact, having two AVPackets is not needed and everything can be
  
  handled by s->buf_pkt.
  This commit removes the local avpkt from v4l2_receive_frame(), meaning
  
  that the ownership transfer doesn't need to be handled and the double
  
  free is fixed.
  Signed-off-by : Andriy Gelman <andriy.gelman@gmail.com>
  

  • [DH] libavcodec/v4l2_m2m_dec.c