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• avcodec/mpeg4videodec : Check available data before reading custom matrix

  29 novembre 2015, par Michael Niedermayer

  avcodec/mpeg4videodec : Check available data before reading custom matrix
  Fixes : out of array read
  
  Fixes : 76c515fc3779d1b838667c61ea13ce92/asan_heap-oob_1fc0d07_8913_794a4629a264ebdb25b58d3a94ed1785.bit
  Found-by : Mateusz "j00ru" Jurczyk and Gynvael Coldwind
  
  Signed-off-by : Michael Niedermayer <michael@niedermayer.cc>
  

  • [DH] libavcodec/mpeg4videodec.c

• FFmpeg recording h264 to a circular buffer "Packet header not contained in global..."

  25 novembre 2015, par user15941

  I’ve made a class which captures a RTSP h264 stream and stores its Packets in a circular buffer. On demand the content of the buffer is dumped to a file with header and trailer. I based the code mainly on : this question example, but by trial and error I came up with three modifications :

  1. I use wrapping object for AVPacket not to bother with memory deallocation.
  2. I convert the data with a filter : "h264_mp4toannexb", so the result file is in .ts format.
  3. I wait in a loop to get a key-frame before any push_back() to circular buffer.

  However something’s wrong with the framerate. The only player, that opens my videos correctly is mplayer. VLC and other players I tested show all the frames in one second.

  ffmpeg lib also reports a lot of error messages : "Packet header is not contained in global metadata", but I don’t know whether the information is held in that header or in some other place ?

  With this code I assign consecutive pts and dts. Then every packet is stored in the circular buffer.

  packet.pts = idx++;
  
  packet.dts = packet.pts;
  
  if (cbuf_mutex.try_lock()) {
  
      cbuf.push_back(PACKET(&packet));
  
      captured_frames++;
  
      if (captured_frames > CBUF_SIZE)
  
          captured_frames = CBUF_SIZE;
  
      cbuf_mutex.unlock();
  
  }
  
  else {
  
      syslog(LOG_ERR, "Buffer mutex was locked - packet skipped");
  
  }

  PACKET class implements copying of the data.
  Is there something missing, which may cause the errors ?

  PACKET::PACKET(const PACKET& rhs)
  
  {
  
      av_new_packet(&packet, rhs.packet.size);
  
      av_copy_packet(&packet, &rhs.packet);
  
  }
  
  
  
  PACKET& PACKET::operator=(const PACKET& rhs)
  
  {
  
      if (&rhs == this)
  
          return *this;
  
      av_free_packet(&packet);
  
      av_new_packet(&packet, rhs.packet.size);
  
      av_copy_packet(&packet, &rhs.packet);
  
      return *this;
  
  }

• movenc-test : Pad the packet data start with 0s

  17 novembre 2015, par Derek Buitenhuis

  movenc-test : Pad the packet data start with 0s
  This way, it never starts with 0xFFF0, and never trips the
  
  ADTS "Detection" code in movenc.c.
  Signed-off-by : Derek Buitenhuis <derek.buitenhuis@gmail.com>
  

  • [DH] libavformat/movenc-test.c
  • [DH] tests/ref/fate/movenc