[Gnash-commit] [patch #8747] Patches to fix 8-bit PCM sound wailing/crashing in FFmpeg media backend

[Nutchanon Wetchasit]

URL:
  <http://savannah.gnu.org/patch/?8747>

                 Summary: Patches to fix 8-bit PCM sound wailing/crashing in
FFmpeg media backend
                 Project: Gnash - The GNU Flash player
            Submitted by: nachanon
            Submitted on: Sun 20 Sep 2015 01:17:21 PM ICT
                Category: sound
                Priority: 5 - Normal
                  Status: None
                 Privacy: Public
             Assigned to: None
        Originator Email: 
             Open/Closed: Open
         Discussion Lock: Any

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Details:

This series of patches fixes FFmpeg backend-specific issue of bug #45722
(PCM embeded sound screeching) in 8-bit PCM audio case.

Note #1: There are multiple issues
<https://savannah.gnu.org/bugs/?45722#comment27> in Gnash's FFmpeg codec and
resampler
backend which are _closely tangled together_. As these patches tries to fix
each of them individually, the symptom will change or worsen as the patching
go,
but will get better at the end where all the patches are completely applied.

Note #2: I haven't tested on multiple variants of FFmpeg/libAV (especially
ones that came with `swresample.h` or `avresample.h`). So it would need
a more intensive review and testing to make sure that this series of fix
doesn't introduce regression on other FFmpeg/libAV version or other non-PCM
codecs.


Patch 1 of 5:
See the attached
`0004_use-source-sample-format-in-ffmpeg-audio-resampler.patch`

Originally, FFmpeg backend's used a hard-coded source sample format
<http://git.savannah.gnu.org/cgit/gnash.git/tree/libmedia/ffmpeg/AudioResamplerFfmpeg.cpp?id=516a6cae2301c582b54d7f00188c8e22c5d76c1b#n64>
(signed PCM 16-bit) when calling FFmpeg/libAV audio resampler, if user's
FFmpeg/libAV version didn't have both `swresample.h` and `avresample.h`.

This patch makes it use the original decoded sample format instead.
(Which could be PCM 8-bit if the original sound is 8-bit PCM
in `UNCOMPRESSED` or `RAW` format)

Note: If `swresample.h` and/or `avresample.h` is available, original
sample format is already used in the resampler invocation.

Gnash: 0.8.11dev (patched against git 516a6ca 15-Sep-2015)
SDL: libsdl1.2debian 1.2.15-5 (debian)
libAV: libavcodec53 6:0.8.17-1 (debian), libavformat53 6:0.8.17-1 (debian),
libavutil51 6:0.8.17-1 (debian)
CSound: libcsound64-5.2 1:5.17.11~dfsg-3 (debian)
System: Debian GNU/Linux 7.0 Wheezy i386



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File Attachments:


-------------------------------------------------------
Date: Sun 20 Sep 2015 01:17:21 PM ICT  Name:
0004_use-source-sample-format-in-ffmpeg-audio-resampler.patch  Size: 793B  
By: nachanon
Patch to make FFmpeg/libAV-based resampler consider decoded sample format in
all cases
<http://savannah.gnu.org/patch/download.php?file_id=34930>

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