Hi.
I'm trying to write an app for voice transmission between two laptops. When
using CVSD, the communication performs ok. However, I would need to transmit
the PCM samples in a transparent mode, for after receiving a voice frame, I
must process the samples.
I have read in Bluetooth 2.0 specification that this can be done, for
example, with 0x0063 as voice settings. I have tried it with my Bluetooth
2.0+EDR dongles but it doesn't work properly. I transmit continuously a
frame with values 0x01 through 0x30, but in the receiver side and using
hcidump, I see that a brust of 0 is inserted in the middle of some frames
and there are hops in the sequence. For instance, I send 0x00 0x01 0x02 0x03
0x04 .... 0x29 0x30, but I receive 0x2e 0x2f 0x30 0x00 0x01 0x02 0x2f 0x30
0x00 0x01.....
Have any of you tested it? Is there any solution to make what I try?
Thanks.
Hey Steven...
For a CSR USB chip when the SCO mapping is over HCI is it possible to change
the voice settings to send PCM samples over the air?
On 4/7/06, Steven Singer <[email protected]> wrote:
>
> Sowmya Gattupalli wrote:
> > On 4/4/06, Israel Gu?o <[email protected]> wrote:
> >> example, with 0x0063 as voice settings. I have tried it with my
> Bluetooth
> > How did u use CVSD when transmitting over sco?? [...]
>
> He was quite clear that he'd used voice settigns 0x0063. The last two
> bits indicate transparent coding and not CVSD.
>
> Israel, you need to be sure you're sending data at exactly the right
> average data rate. SCO links are synchronous and if you don't provide
> data at exactly the right rate then something somewhere in the
> system will have to insert or delete samples.
>
> It would also be helpful if you stated what chip and firmware version
> you were using.
>
> - Steven
> --
>
>
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Sowmya Gattupalli wrote:
> On 4/4/06, Israel Gu=EDo <[email protected]> wrote:
>> example, with 0x0063 as voice settings. I have tried it with my Blueto=
oth
> How did u use CVSD when transmitting over sco?? [...]
He was quite clear that he'd used voice settigns 0x0063. The last two
bits indicate transparent coding and not CVSD.
Israel, you need to be sure you're sending data at exactly the right
average data rate. SCO links are synchronous and if you don't provide
data at exactly the right rate then something somewhere in the
system will have to insert or delete samples.
It would also be helpful if you stated what chip and firmware version
you were using.
- Steven
--=20
To access the latest news from CSR copy this link into a web browser: ht=
tp://http://www.csr.com/email_sig.php
-------------------------------------------------------
This SF.Net email is sponsored by xPML, a groundbreaking scripting language
that extends applications into web and mobile media. Attend the live webcast
and join the prime developer group breaking into this new coding territory!
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Hi.
That is really the core of my question, and I expect somebody could answer
it. I try to transmit PCM samples without any sort of modulation but I
can't.
Bye!
HI....
How do i change it to PCM using hciconfig ?? I think as you said the default
is CVSD... how can I change the voice setting from CVSD to PCM??
regards
Soumya
On 4/6/06, Israel Gu?o <[email protected]> wrote:
>
> Hi Sowmya.
>
> I don't use /dev/dsp to get audio samples. I use ALSA project library and
> it works (I suggest you should look for code samples about it, specially
> those regarding to headsets).
>
> CVSD is the default on-the-air coding for SCO packets but you can change
> it by means of "hciconfig".
>
> For SCO transmission, just open a socket as in scotest.c(bluez-utils/test) and use write and read on it.
>
> There is no documentation about BlueZ and, if you want to use it, you must
> read and undestand the code.
>
> Bye!
>
>
>
> >Hey Israel,
> >How did u use CVSD when transmitting over sco?? U mean u used some sort
> of
> >function to convert the voice you input from /dev/dsp into CVSD codec??
> >Can u also throw some light on CVSD and SCO... I mean how are u
> transmittin=
> >g
>
> >the packets over SCO??
>
> >Soumya
>
Hi Sowmya.
I don't use /dev/dsp to get audio samples. I use ALSA project library and it
works (I suggest you should look for code samples about it, specially those
regarding to headsets).
CVSD is the default on-the-air coding for SCO packets but you can change it
by means of "hciconfig".
For SCO transmission, just open a socket as in scotest.c (bluez-utils/test)
and use write and read on it.
There is no documentation about BlueZ and, if you want to use it, you must
read and undestand the code.
Bye!
>Hey Israel,
>How did u use CVSD when transmitting over sco?? U mean u used some sort of
>function to convert the voice you input from /dev/dsp into CVSD codec??
>Can u also throw some light on CVSD and SCO... I mean how are u
transmittin=
>g
>the packets over SCO??
>Soumya
Hey Israel,
How did u use CVSD when transmitting over sco?? U mean u used some sort of
function to convert the voice you input from /dev/dsp into CVSD codec??
Can u also throw some light on CVSD and SCO... I mean how are u transmitting
the packets over SCO??
Soumya
On 4/4/06, Israel Gu?o <[email protected]> wrote:
>
> Hi.
>
> I'm trying to write an app for voice transmission between two laptops.
> When using CVSD, the communication performs ok. However, I would need to
> transmit the PCM samples in a transparent mode, for after receiving a voice
> frame, I must process the samples.
>
> I have read in Bluetooth 2.0 specification that this can be done, for
> example, with 0x0063 as voice settings. I have tried it with my Bluetooth
> 2.0+EDR dongles but it doesn't work properly. I transmit continuously a
> frame with values 0x01 through 0x30, but in the receiver side and using
> hcidump, I see that a brust of 0 is inserted in the middle of some frames
> and there are hops in the sequence. For instance, I send 0x00 0x01 0x02 0x03
> 0x04 .... 0x29 0x30, but I receive 0x2e 0x2f 0x30 0x00 0x01 0x02 0x2f 0x30
> 0x00 0x01.....
>
> Have any of you tested it? Is there any solution to make what I try?
>
> Thanks.
>