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• x86inc : Clear __SECT__

  26 mai 2015, par Timothy Gu

  x86inc : Clear __SECT__
  Silences warning(s) like :
      libavcodec/x86/fft.asm:93 : warning : section flags ignored on
  
      section redeclaration
  The cause of this warning is that because `struc` and `endstruc`
  
  attempts to revert to the previous section state [1].
  The section state is stored in the macro __SECT__, defined by
  
  x86inc.asm to be `.note.GNU-stack ...`, through the `SECTION`
  
  directive [2].
  Thus, the `.note.GNU-stack` section is defined twice
  
  (once in x86inc.asm, once during `endstruc`), causing the warning.
  That is the first part of the commit : using the primitive `[section]` format
  
  for .note.GNU-stack etc., which does not update `__SECT__` [2].
  That fixes only half of the problem. Even without any `SECTION` directives,
  
  `__SECT__` is predefined as `.text`, which conflicting with the later
  
  `SECTION_TEXT` (which expands to `.text align=16`).
  [1] : http://www.nasm.us/doc/nasmdoc6.html#section-6.4
  
  [2] : http://www.nasm.us/doc/nasmdoc6.html#section-6.3
  Signed-off-by : Luca Barbato <lu_zero@gentoo.org>
  

  • [DBH] libavutil/x86/x86inc.asm

• Audioqueue try to read ADPCM sound

  4 septembre 2013, par Kamax

  I try to read a .asf stream with FFMPEG and the audio part is ADPCM IMA WAV codec.

  The sound i hear when i hear something is only noise. I suppose my AudioStreamBasicDescription are wrong. How can i get the correct values ?

  From ffprobe i have this :

  [STREAM]
  
  index=1
  
  codec_name=adpcm_ima_wav
  
  codec_long_name=ADPCM IMA WAV
  
  codec_type=audio
  
  codec_time_base=1/8000
  
  codec_tag_string=[17][0][0][0]
  
  codec_tag=0x0011
  
  sample_rate=8000.000000 
  
  channels=1
  
  bits_per_sample=4
  
  r_frame_rate=0/0
  
  avg_frame_rate=250/41
  
  time_base=1/1000
  
  start_time=0.000000 
  
  duration=N/A
  
  [/STREAM]

  and

  Stream #0.1: Audio: adpcm_ima_wav, 8000 Hz, 1 channels, s16, 32 kb/s

  my code for the moment is :

  asbd.mSampleRate = 8000;
  
  asbd.mFormatID = kAudioFormatAppleIMA4;
  
  asbd.mBytesPerPacket = 34;
  
  asbd.mFramesPerPacket = 64;
  
  asdb.mbitsPerChannel = 1;

  All the rest is to 0 (flags, byte per frame, bits per channel, reserved).

  Edit :

  I just find that the codec code 17 is maybe for kAudioFormatDVIIntelIMA and not kAudioFormatAppleIMA4. Can someone confirm this ?

  This is from ffprobe :

  [PACKET]
  
  codec_type=audio
  
  stream_index=1
  
  pts=11200
  
  pts_time=11.200000 
  
  dts=11200
  
  dts_time=11.200000 
  
  duration=164
  
  duration_time=0.164000 
  
  size=656.000000 
  
  pos=1171105
  
  flags=K
  
  [/PACKET]

  Is the size 656 for mBytesperpacket ?

  With this value and the half 328 for mFramesPerPacket i can hear something but it's not continuous and has a lot of noise.

  Please help !

• Why does subprocess.run() have unexpected behavior in try else block ?

  27 novembre 2023, par Nikita Savenkov

  Trying to make a "to mp4" converter function using ffmpeg that is going to convert a file to mp4, delete the original file, and return True or False for specific conditions.
But I get some unexpected behavior of a subprocess.

  


  Initially I used this construction :

  


  def to_mp4_converter(file):

    input_file = file
    output_file = f"{re.sub(r'\..+$', "", file)}.mp4"

    try:
        subprocess.run(['ffmpeg', '-i', input_file, output_file])
    except subprocess.SubprocessError as e:
        print(f"Subprocess Error: {e}")
        return False
    else:
        try:
            os.remove(path=file)
        except OSError as e:
            print(f"Can't remove {file} file: {e}")
        finally:
            return True


  


  Original file is removed, but output file is half of the expected size and quality of video is low.

  


  But if I place subprocess.run() and os.remove() into separate try else blocks like that :

  


  def to_mp4_converter(file):

    input_file = file
    output_file = f"{re.sub(r'\..+$', "", file)}.mp4"

    try:
        subprocess.run(['ffmpeg', '-i', input_file, output_file])
    except subprocess.SubprocessError as e:
        print(f"Subprocess Error: {e}")
        return False
    else:
        pass

    try:
        os.remove(path=file)
    except OSError as e:
        print(f"Can't remove {file} file: {e}")
    finally:
        return True


  


  Everything works fine.

  


  Isn't subprocess.run() should be a blocking operation, so the else statement in 1st example is unreachable until conversion is done ?