[Bug 14717] resampled sound is horrible

[wine-bugs at winehq.org]

http://bugs.winehq.org/show_bug.cgi?id=14717





--- Comment #4 from Alexander E. Patrakov <patrakov at gmail.com>  2009-02-03 00:33:34 ---
The bug still exists and is easily triggered by playing music by Caravelli
(album: grand prix) in foobar2000. Anyway, you can check for this bug yourself
using the procedure below and any mp3 file containing music.

1. Install Jack (and, for convenience, qjackctl) and recompile wine so that it
has a Jack output driver. Install PortAudio with the Jack backend, install
Audacity.

2. Start Jack (preferrably, using qjackctl) with 192 kHz sampling rate and two
channels (assuming that your hardware supports it). The intention is to make
long runs of the same sample easily visible in the recorded waves. Verify that
you can record from Jack in Audacity.

3. Using winecfg, select Jack as the output driver, set "Emulation" as the hw
acceleration level, and tick the "Emulation" checkbox (not sure if this step is
relevant)

4. Using regedit, go to the HKEY_CURRENT_USER\Software\Wine\DirectSound key,
and change the DefaultSampleRate value to 192000.

5. Install foobar2000 in wine and run it. Start playing a long sound file.

6. Start audacity, select 192000 Hz as the project sampling rate, select
wine_jack_out_0 as the recording source, start recording. jackrec may work,
too, but I didn't test it.

7. Record several seconds of wine output through jack in audacity. Export as a
32-bit headerless raw file.

8. Look at the raw file with a hex editor, or use the following command:

od -A d -v -t d4 --width=8 wine.raw | less

Here is part of the output from my file:

0000000  -572671040  -563692352
0000008  -572671040  -563692352
0000016  -572671040  -563692352
0000024  -357640864  -732190528
0000032  -357640864  -732190528
0000040  -357640864  -732190528
0000048  -357640864  -732190528
0000056  -326575840  -840262720
0000064  -326575840  -840262720
0000072  -326575840  -840262720
0000080  -326575840  -840262720
0000088  -336275488  -845636800
0000096  -336275488  -845636800
0000104  -336275488  -845636800
0000112  -336275488  -845636800
0000120  -336275488  -845636800
0000128  -209590528  -826761856
0000136  -209590528  -826761856
0000144  -209590528  -826761856
0000152  -209590528  -826761856
0000160   -81791424  -820666816

You can clearly see the long runs of duplicated sample values, which means that
wine is using zero-order-hold resampling.

Also, in audacity, you can look at the spectrum of what you recorded. Ideally,
below half of the sampling rate of the sound file, it should exactly match
what's in the sound file, while above that, it should be zero. Actually, there
are distortions of -30 dB both above and below that frequency on real music
files.


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