2006-11-09 10:02:53

by Marcel Hilzinger

[permalink] [raw]
Subject: [Bluez-devel] Quality of a2dp sound

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2006-11-13 15:32:18

by Brad Midgley

[permalink] [raw]
Subject: Re: [Bluez-devel] Quality of a2dp sound

Reiner

> What I did notice is that the volume could be higher and there is the
> occasional faint clicking which might be due to clipping.

I did try to hunt these down for a good while but didn't have a lot of
luck. It came down to a balance of one problem or the other. :(

I was thinking recently both these could be solved by doing dynamic
compression before encoding the audio. It would reduce the dynamic range
however.

Brad

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2006-11-10 08:01:16

by Marcel Hilzinger

[permalink] [raw]
Subject: Re: [Bluez-devel] Quality of a2dp sound

Am Donnerstag, 9. November 2006 11:07 schrieb Reiner Klenk:
> Hi,
> I'm also using a BT620s and I find the sound quality acceptable using
> the a2dp plugin. I also tested with a2dpd and there wasn't any
> difference in sound quality that I could perceive. =

Then we must have different ears :-) or different versions. I'm using Suse =

Linux 10.1 with kernel 2.6.16.21, alsa-version is 1.0.13

a2dpd produces some noise in the background. If there is silence, you can h=
ear =

it. With a2play there is no noise. I will checkout cvs again and have a loo=
k.

> However, with a2dp, =

> which I'm using with amarok I can actually play mono/stereo sources with
> different sample rates without getting the pitch problem (Frederic has
> submitted patches for a2dpd recently but I haven't tested them yet).
How do you change the sample rate?

> I'm =

> using a 100 mW dongle and there are no drop-outs within my (not too big)
> appartment. It seems to be fairly stable, I have used the headset for
> hours without a glitch.
> What I did notice is that the volume could be higher and there is the
> occasional faint clicking which might be due to clipping. As far as I
> understood these are known issues inside the sbc encoding library.
> Of course, headsets like the BT620s can be connected via SCO as well as
> a2dp. Use SCO to hook it up to your phone or to egika, but definitly use
> a2dp for the connection to amarok or other music/podcast players.
>
> Regards,
> Reiner
>
>
>
> -------------------------------------------------------------------------
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> Get stuff done quickly with pre-integrated technology to make your job
> easier Download IBM WebSphere Application Server v.1.0.1 based on Apache
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=3D121642
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-- =

Mit freundlichen Gr=FC=DFen,
Marcel Hilzinger

Linux New Media AG
S=FCskindstr. 4
D-81929 M=FCnchen
Tel: +49 (89) 99 34 11 0
Fax: +49 (89) 99 34 11 99

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2006-11-09 19:31:57

by Thomas Kear

[permalink] [raw]
Subject: Re: [Bluez-devel] Quality of a2dp sound

You should be able to use the command line encoding tools in their
decode modes to play most formats. For example:

flac -c -d [file] | aplay
lame --decode [file] - | aplay
oggdec -c [file] | aplay (not so sure about this one, some command
switches are like flac, some aren't)

Should stretch to some other formats too, wavpack springs to mind
(although i can't remember its command line syntax).


On 10/11/06, Marcel Hilzinger <[email protected]> wrote:
> Am Donnerstag, 9. November 2006 11:42 schrieb Adrian Glaubitz:
> > Hi Marcel !
> >
> > Marcel Hilzinger schrieb:
> > > Hi,
> > >
> > > I made some tests with bluetooth stereo headsets and a2dpd.
> > > I must confess, I'm impressed by the easy use of a2dpd! Thanks, it's =
just
> > > great.
> >
> > Yes, the usage is very simple, indeed. Once I figured out how to use
> > passkey-agent, the connection worked immediately ;).
> >
> > > But I'm not impressed by the audio quality. Its quite noisy and far a=
way
> > > from the quality of normal wireless headphones. Headset was a Jabra
> > > BT620s. I tried with different dongles, but the dongle seems to make =
no
> > > difference.
> >
> > My problem with the audio quality and a2dpd is, that the quality is set
> > to telephone quality only (8kHz, Mono) though my headset can do up to
> > 44,1kHz Stereo (SONY VGP-BRM1D) and a2dpd even displays 44,1kHz. When
> > using a2play I can listen in 44,1kHz quality, so this is an issue with
> > a2dpd for me (but a2play plays the MP3s with higher speed, so they sound
> > high-pitched). Also the sound is chopped very often with a2dpd, so this=
is
> > no use for me at the moment :(.
> >
> > > Questions:
> > > is this a problem of the technology?
> >
> > I don't think so, this is rather due to the fact that btsco is still in
> > Alpha status of development.
> >
> > > is it a problem of bluez?
> >
> > No, I'd rather blame btsco. (I tried different kernel versions, 2.6.17.9
> > and 2.6.19-rc5 and the most recent bluez-utils version).
> >
> > > did I something wrong?
> >
> > Have you tried a2play instead ? Do this:
> >
> > - hcitool scan
> > - passkey-agent <code> <address>
> > - btsco -r -v <address>
> > - mpg123 --au - file.mp3 | a2play <address>
>
> Hey, thanks! I tried this once before, but it didn't work. So I gave up. =
But
> now it works like a charm and yes, sound quality is better.
>
> However, with this solution I can only play MP3 files. But most of my
> collection is in OGG-Vorbis. And how to skip to next/previous track?
>
>
> > > did anybody compare the quality on Windows? I tried to compare with M=
ac.
> > > But as Mac OS X cannot do a2dpd, it's even worse on Mac.
> >
> > I was not able to use my headset in Windows, Windows doesn't give me any
> > options for choosing the headset as an audio output-device, though I can
> > to the headset successfully. On 2 Macintosh Mini (Intel and PPC) with OS
> > 10.4 I was able to connect to the headset without any problems, and I c=
ould
> > choose my headset for all the sound-output so I was able to listen to
> > iTunes via the headset. The only drawback on the Mac is, that the
> > quality is limited to 8000Hz, 16 Bit mono (and the Audio Utility won't
> > let me choose any better quality, though the headset supports this).
> Mac does not support a2dp, that's why the quality is bad.
>
>
> --
> Mit freundlichen Gr=FC=DFen,
> Marcel Hilzinger
>
> Linux New Media AG
> S=FCskindstr. 4
> D-81929 M=FCnchen
> Tel: +49 (89) 99 34 11 0
> Fax: +49 (89) 99 34 11 99
>
> -------------------------------------------------------------------------
> Using Tomcat but need to do more? Need to support web services, security?
> Get stuff done quickly with pre-integrated technology to make your job ea=
sier
> Download IBM WebSphere Application Server v.1.0.1 based on Apache Geronimo
> http://sel.as-us.falkag.net/sel?cmd=3Dlnk&kid=3D120709&bid=3D263057&dat=
=3D121642
> _______________________________________________
> Bluez-devel mailing list
> [email protected]
> https://lists.sourceforge.net/lists/listinfo/bluez-devel
>


-- =

Thomas Kear
[email protected]
+6421996486

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2006-11-09 10:07:33

by Reiner Klenk

[permalink] [raw]
Subject: Re: [Bluez-devel] Quality of a2dp sound

Hi,
I'm also using a BT620s and I find the sound quality acceptable using
the a2dp plugin. I also tested with a2dpd and there wasn't any
difference in sound quality that I could perceive. However, with a2dp,
which I'm using with amarok I can actually play mono/stereo sources with
different sample rates without getting the pitch problem (Frederic has
submitted patches for a2dpd recently but I haven't tested them yet). I'm
using a 100 mW dongle and there are no drop-outs within my (not too big)
appartment. It seems to be fairly stable, I have used the headset for
hours without a glitch.
What I did notice is that the volume could be higher and there is the
occasional faint clicking which might be due to clipping. As far as I
understood these are known issues inside the sbc encoding library.
Of course, headsets like the BT620s can be connected via SCO as well as
a2dp. Use SCO to hook it up to your phone or to egika, but definitly use
a2dp for the connection to amarok or other music/podcast players.

Regards,
Reiner



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2006-11-09 17:43:50

by Marcel Hilzinger

[permalink] [raw]
Subject: Re: [Bluez-devel] Quality of a2dp sound

Am Donnerstag, 9. November 2006 11:42 schrieb Adrian Glaubitz:
> Hi Marcel !
>
> Marcel Hilzinger schrieb:
> > Hi,
> >
> > I made some tests with bluetooth stereo headsets and a2dpd.
> > I must confess, I'm impressed by the easy use of a2dpd! Thanks, it's ju=
st
> > great.
>
> Yes, the usage is very simple, indeed. Once I figured out how to use
> passkey-agent, the connection worked immediately ;).
>
> > But I'm not impressed by the audio quality. Its quite noisy and far away
> > from the quality of normal wireless headphones. Headset was a Jabra
> > BT620s. I tried with different dongles, but the dongle seems to make no
> > difference.
>
> My problem with the audio quality and a2dpd is, that the quality is set
> to telephone quality only (8kHz, Mono) though my headset can do up to
> 44,1kHz Stereo (SONY VGP-BRM1D) and a2dpd even displays 44,1kHz. When
> using a2play I can listen in 44,1kHz quality, so this is an issue with
> a2dpd for me (but a2play plays the MP3s with higher speed, so they sound
> high-pitched). Also the sound is chopped very often with a2dpd, so this is
> no use for me at the moment :(.
>
> > Questions:
> > is this a problem of the technology?
>
> I don't think so, this is rather due to the fact that btsco is still in
> Alpha status of development.
>
> > is it a problem of bluez?
>
> No, I'd rather blame btsco. (I tried different kernel versions, 2.6.17.9
> and 2.6.19-rc5 and the most recent bluez-utils version).
>
> > did I something wrong?
>
> Have you tried a2play instead ? Do this:
>
> - hcitool scan
> - passkey-agent <code> <address>
> - btsco -r -v <address>
> - mpg123 --au - file.mp3 | a2play <address>

Hey, thanks! I tried this once before, but it didn't work. So I gave up. Bu=
t =

now it works like a charm and yes, sound quality is better.

However, with this solution I can only play MP3 files. But most of my =

collection is in OGG-Vorbis. And how to skip to next/previous track?


> > did anybody compare the quality on Windows? I tried to compare with Mac.
> > But as Mac OS X cannot do a2dpd, it's even worse on Mac.
>
> I was not able to use my headset in Windows, Windows doesn't give me any
> options for choosing the headset as an audio output-device, though I can
> to the headset successfully. On 2 Macintosh Mini (Intel and PPC) with OS
> 10.4 I was able to connect to the headset without any problems, and I cou=
ld
> choose my headset for all the sound-output so I was able to listen to
> iTunes via the headset. The only drawback on the Mac is, that the
> quality is limited to 8000Hz, 16 Bit mono (and the Audio Utility won't
> let me choose any better quality, though the headset supports this).
Mac does not support a2dp, that's why the quality is bad.


-- =

Mit freundlichen Gr=FC=DFen,
Marcel Hilzinger

Linux New Media AG
S=FCskindstr. 4
D-81929 M=FCnchen
Tel: +49 (89) 99 34 11 0
Fax: +49 (89) 99 34 11 99

-------------------------------------------------------------------------
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Subject: Re: [Bluez-devel] Quality of a2dp sound

Hi Marcel !

Marcel Hilzinger schrieb:
> Hi,
> =

> I made some tests with bluetooth stereo headsets and a2dpd. =

> I must confess, I'm impressed by the easy use of a2dpd! Thanks, it's just =

> great. =


Yes, the usage is very simple, indeed. Once I figured out how to use
passkey-agent, the connection worked immediately ;).

> =

> But I'm not impressed by the audio quality. Its quite noisy and far away =
from =

> the quality of normal wireless headphones. Headset was a Jabra BT620s. I =

> tried with different dongles, but the dongle seems to make no difference.

My problem with the audio quality and a2dpd is, that the quality is set
to telephone quality only (8kHz, Mono) though my headset can do up to
44,1kHz Stereo (SONY VGP-BRM1D) and a2dpd even displays 44,1kHz. When
using a2play I can listen in 44,1kHz quality, so this is an issue with a2dpd
for me (but a2play plays the MP3s with higher speed, so they sound
high-pitched). Also the sound is chopped very often with a2dpd, so this is =
no use for me
at the moment :(.

> =

> Questions: =

> is this a problem of the technology?

I don't think so, this is rather due to the fact that btsco is still in
Alpha status of development.

> is it a problem of bluez?

No, I'd rather blame btsco. (I tried different kernel versions, 2.6.17.9
and 2.6.19-rc5 and the most recent bluez-utils version).

> did I something wrong?

Have you tried a2play instead ? Do this:

- hcitool scan
- passkey-agent <code> <address>
- btsco -r -v <address>
- mpg123 --au - file.mp3 | a2play <address>

> =

> did anybody compare the quality on Windows? I tried to compare with Mac. =
But =

> as Mac OS X cannot do a2dpd, it's even worse on Mac.


I was not able to use my headset in Windows, Windows doesn't give me any
options for choosing the headset as an audio output-device, though I can
to the headset successfully. On 2 Macintosh Mini (Intel and PPC) with OS 10=
.4
I was able to connect to the headset without any problems, and I could
choose my headset for all the sound-output so I was able to listen to
iTunes via the headset. The only drawback on the Mac is, that the
quality is limited to 8000Hz, 16 Bit mono (and the Audio Utility won't
let me choose any better quality, though the headset supports this).

> =

> Regards,
> -- =

> =DCdv=F6zlettel -- Mit freundlichen Gr=FCssen,
> Marcel Hilzinger


Greetings,

Adrian

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