[Gnash-commit] [bug #45722] Gnash emitted loud screech after playing PCM audio object

[Nutchanon Wetchasit]

Follow-up Comment #14, bug #45722 (project gnash):

Regarding "PCM decoder" mentioned in comment 12
<https://savannah.gnu.org/bugs/?45722#comment12>:

* With `gnash --media=ffmpeg`, PCM decoding (and sample format conversion) is
done through FFmpeg/libAV:
** PCM decoder is handled by Gnash's `AudioDecoderFfmpeg.decode()`
<http://git.savannah.gnu.org/cgit/gnash.git/tree/libmedia/ffmpeg/AudioDecoderFfmpeg.cpp?id=c969f9d9d9ac40bfcb8e7c19b0f8ff5345f57c2d#n313>,
which calls `AudioDecoderFfmpeg.decodeFrame()`
<http://git.savannah.gnu.org/cgit/gnash.git/tree/libmedia/ffmpeg/AudioDecoderFfmpeg.cpp?id=c969f9d9d9ac40bfcb8e7c19b0f8ff5345f57c2d#n445>,
which calls libAV's decoding functions.
** Resampler is handled by Gnash's `AudioResamplerFfmpeg` class
<http://git.savannah.gnu.org/cgit/gnash.git/tree/libmedia/ffmpeg/AudioResamplerFfmpeg.cpp?id=c969f9d9d9ac40bfcb8e7c19b0f8ff5345f57c2d>.
In my case, it calls libAV's `audio_resample()` function. 
* With `gnash --media=gst`, PCM decoding (and sample format conversion) is
done entirely in Gnash:
** PCM decoder is Gnash's `AudioDecoderSimple.decode()` line 396-496
<http://git.savannah.gnu.org/cgit/gnash.git/tree/libmedia/AudioDecoderSimple.cpp?id=c969f9d9d9ac40bfcb8e7c19b0f8ff5345f57c2d#n396>.
** Resampler implementation is Gnash's `AudioResampler.convert_raw_data()`
<http://git.savannah.gnu.org/cgit/gnash.git/tree/libmedia/AudioResampler.cpp?id=c969f9d9d9ac40bfcb8e7c19b0f8ff5345f57c2d#n28>.

Gnash: 0.8.11dev (git ba8ab1d 07-Sep-2015)
libAV: libavcodec53 6:0.8.17-1 (debian), libavformat53 6:0.8.17-1 (debian),
libavutil51 6:0.8.17-1 (debian), libav-tools 6:0.8.10-1 (debian) 
System: Debian GNU/Linux 7.0 Wheezy i386


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