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• avformat_open_input fails intermittently with avfoundation due to "audio format is not supported"

  27 septembre 2019, par NaderNader

  My application uses the ffmpeg APIs (avformat, avdevice, etc) to open a selected audio input for encoding. For some inputs I can reliably open them the first time, but when I close and reopen that input later, the avformat_open_input() call fails due to "audio format is not supported". My testing shows that it never fails the first time after starting my, and has only about a 50% chance of success when reopening.

  The failure only occurs with my "Built-in Microphone" audio input. I have a USB audio card that reliably opens and closes repeatedly. I have read the documentation and see that the proper way to free the resources after opening is to call avformat_close_input. The only way I have found to guarantee success is to only open the input once.

  I have written a test program to recreate these failures.

  int main() {
  
  
  
      avdevice_register_all();
  
  
  
      cout << "Running open audio test" << endl;
  
  
  
  
  
      int i;
  
      for(i = 0; i< 10; i++) {
  
  
  
          AVDictionary* options = NULL;
  
          AVInputFormat* inputFormat = av_find_input_format("avfoundation");
  
          if (!inputFormat) {
  
              cout << "avfoundation inputFormat=null" << endl;
  
          }
  
  
  
          AVFormatContext* formatContext = avformat_alloc_context();
  
          int result = avformat_open_input(&formatContext, ":1", inputFormat, &options);
  
          if (result < 0) {
  
              char error[256];
  
              av_strerror(result, error, sizeof(error));
  
              cout << "result=" << result << " " << error << endl;
  
          } else {
  
              cout << "input opened successfully" << endl;
  
          }
  
  
  
          sleep(1);
  
  
  
          avformat_close_input(&formatContext);
  
  
  
          sleep(1);
  
  
  
      }
  
  
  
      return 0;
  
  }

  I would expect the main loop to succeed each time but a typical output shows a high failure rate :

  Running open audio test

  input opened successfully
  
  [avfoundation @ 0x7fdeb281de00] audio format is not supported
  
  result=-5 Input/output error
  
  [avfoundation @ 0x7fdeb2001400] audio format is not supported
  
  result=-5 Input/output error
  
  [avfoundation @ 0x7fdeb2001400] audio format is not supported
  
  result=-5 Input/output error
  
  input opened successfully
  
  input opened successfully
  
  input opened successfully
  
  [avfoundation @ 0x7fdeb2068800] audio format is not supported
  
  result=-5 Input/output error
  
  input opened successfully
  
  input opened successfully

  I have tried increasing the sleep time between close and open to 5 seconds, but saw no difference in behavior.

  The source of the failure is https://github.com/FFmpeg/FFmpeg/blob/master/libavdevice/avfoundation.m#L672

  It appears avfoundation.m internally is opening an input stream and grabbing an audio frame to determine the format, but the value returned is not valid sometimes, when the process has previously opened and closed that input.

  Am I not closing the resources properly ? Do I have a hardware issue specific to my macbook ?

  Additional Details :

  Tested MacBook Pro with MacOS Mojave 10.14.6
  Tested with Ffmpeg 3.4.1, 4.0, and 4.1

  list_devices :

  [AVFoundation input device @ 0x7f80fff066c0] AVFoundation video devices:
  
  [AVFoundation input device @ 0x7f80fff066c0] [0] FaceTime HD Camera
  
  [AVFoundation input device @ 0x7f80fff066c0] [1] Capture screen 0
  
  [AVFoundation input device @ 0x7f80fff066c0] AVFoundation audio devices:
  
  [AVFoundation input device @ 0x7f80fff066c0] [0] Behringer Duplex
  
  [AVFoundation input device @ 0x7f80fff066c0] [1] Built-in Microphone
  
  [AVFoundation input device @ 0x7f80fff066c0] [2] USB Audio CODEC

• avcodec/pnm_parser : Use memmove() to handle "overread"

  1er août 2019, par Michael Niedermayer

  avcodec/pnm_parser : Use memmove() to handle "overread"
  This is significantly faster
  Fixes : Timeout (1sec after this and the previous commit)
  
  Fixes : 15558/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_PPM_fuzzer-5705273643106304
  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/pnm_parser.c

• "C compiler not found" compiling NDK code Mac

  4 mai 2019, par Zia ur Rehman

  I am trying to compile ffmpeg wrapper GitHub link but getting issues in configuring it. In build_ffmpeg_for_android.sh file I have following lines at start and these are not working so far.

  PREFIX_DIR=$PWD/ffmpeg-android-sdk
  
  SYSROOT=$NDK_HOME/platforms/android-19/arch-arm/
  
  CROSS_COMPILE=$NDK_HOME/toolchains/arm-linux-androideabi- 
  
  4.9/prebuilt/windows/bin/arm-linux-androideabi-
  
  EXTRA_CFLAGS="-I$PREFIX_DIR/include -DANDROID -DNDEBUG -Os -ffast-math -mfpu=neon-vfpv4 -mfloat-abi=softfp"
  
  EXTRA_LDFLAGS="-L$PREFIX_DIR/lib"
  
  
  
  #++ build x264 ++#
  
  if true; then
  
  if [ ! -d x264 ]; then
  
     git clone -b stable git://git.videolan.org/x264.git
  
  fi
  
  cd x264
  
  ./configure --prefix=$PREFIX_DIR \
  
  --enable-strip \
  
  --enable-static \
  
  --enable-pic \
  
  --disable-cli \
  
  --disable-opencl \
  
  --disable-avs \
  
  --host=arm-linux-androideabi \
  
  --cross-prefix=$CROSS_COMPILE \
  
  --sysroot=$SYSROOT

  Error that I am unable to get rid of is "C compiler not found". I have verified all paths mentioned at top of file and added missing paths to env too but still same issue. I have tried it in ubuntu too and facing same issue there. Many users faced similar issues but those fixes are not seems to be working for me. Any pointers will be helpful.

  FYI : I have not worked on NDK much therefore there might be something silly that i have missed.