Hello Frans,
thank you for the patch!!
Christian
From: Frans de Bont
[mailto:frans.de.bont@xxxxxxxxxxx]
Sent: Thursday, October 30, 2008 2:34 PM
To: Christian Hoene
Subject: RE: REALLY Bad encoding performance of Linux SBC
audio codec
Hello
Christian,
I had a quick
look into the bluez sbc decoder test application.
I discovered
that the buffering was not correct.
Attached a
modified version.
Please note
that the output level of the decoder is still 6 dB too low.
This wouldn't
be too difficult to fix for the bluez developers.
Best regards,
Frans
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"Christian
Hoene" <hoene@xxxxxxxxxxxxxxxx>
2008-10-29
04:30 PM
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To
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"'BlueZ
development'" <bluez-devel@xxxxxxxxxxxxxxxxxxxxx>
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|
cc
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Frans
de Bont/EHV/APPTECH/PHILIPS@PHILIPS
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Subject
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RE:
REALLY Bad encoding performance of Linux SBC
audio codec
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Classification
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Hello,
Sorry Bad news.
the encoding and decodng performance of bluez's SBC is really bad.
I just used the latest sbcenc program from bluez-4.17 and compared it to
the
reference
Attached you will find wav-files encoded with the Bluetooth reference
implementation and bluez
Filelist
========
compare.sh
is the scrip that I use to compare both codec
versions
refsop01.wav the original sample
tmp.ref.sbc with reference encoded
tmp.bluez.sbc with bluez encoded
tmp.ref.sw.wav with reference encoded and decoded (has
good quality)
tmp.bluez.sw.wav with bluez encoded and decoded (has bad
quality ODG=)
tmp.refbluez.sw.wav with reference encoded and with bluez decoded (has bad
quality)
tmp.bluezref.sw.wav with bluez encoded and with reference decoded (has
medium quality)
Both the bluez encoder and decoder do not work as good as the reference
implementation.
I also conducted some perceptual audio tests with ITU BS.1387 (PEAQ), which
confirm these results.
With best regards,
Christian
PS:
Attached also an enhanced version for sbc/sbcenc.c, which considers more
command line options.
> -----Original Message-----
> From: Marcel Holtmann [mailto:marcel@xxxxxxxxxxxx]
> Sent: Monday, October 27, 2008 8:42 PM
> To: BlueZ development
> Subject: Re: Bad encoding performance of Linux SBC audio
> codec
>
> Hi Brad,
>
> > > I am sorry to say that the audio quality of the open source
version
> of SBC
> > > is far worse than the reference implementation.
> >
> > If you are using the standalone "sbc" project at
sourceforge, then
> you
> > should try the version inside bluez. The standalone used to
simply be
> > slower, but we identified & fixed some quality issues too
that should
> > be backported.
>
> the standalone version should not be used at all at the moment. All
> efforts should go into the version included in bluez-4.x.tar.gz.
>
> Regards
>
> Marcel
>
>
>
>
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[attachment "sbcenc.c" deleted by Frans de
Bont/EHV/APPTECH/PHILIPS] [attachment "compare.tar.gz" deleted by
Frans de Bont/EHV/APPTECH/PHILIPS]
|
Attachment:
sbcdec.c
Description: Binary data
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