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Low quality audio on Bluetooth Headset

Bluez-users Manuel Naranjo 3 participants 5 messages Nov 15, 2006 – Nov 16, 2006 Bluetooth drivers

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Manuel Naranjo

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#0 lore raw

Hi everyone,
I have a pair of Hifi bluetooth hearphones, that AIRcable (www.aircable.net) send to me. I use it under Windows and Linux, it cames with a usb bt dongle, that is recognized as a usb-sound card which works perfectly, the thing is that when I try to use the headset with a generic Bluetooth Dongle (using a2dpd) I get very low quality audio. I think the headphones work at 22kHz, and I don't get more than 11kHz when I use a2dpd, is there anything that I can do to fix this (including doing some code :D)
Cheers,
Manuel

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#1 lore raw

Manuel

Quoted 8 lines

I have a pair of Hifi bluetooth hearphones, that AIRcable (www.aircable.net) send to me. I use it under Windows and Linux, it cames with a usb bt dongle, that is recognized as a usb-sound card which works perfectly, the thing is that when I try to use the headset with a generic Bluetooth Dongle (using a2dpd) I get very low quality audio. I think the headphones work at 22kHz, and I don't get more than 11kHz when I use a2dpd, is there anything that I can do to fix this (including doing some code :D)

what kind of quality problem? Is it only the low sampling rate or is it one of the other problems? (low volume... popping sounds... played too fast or slow... static...)

a2dp headsets are required to support 44.1khz btw.

Brad

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#2 lore raw
Quoted 4 lines

what kind of quality problem? Is it only the low sampling rate or is it one of the other problems? (low volume... popping sounds... played too fast or slow... static...)

Very low sampling rate, it must be working about 10kHz. And I also get disconnection problems, but this can be due to problems on my usb connectors, they aren't working very well lately.

Quoted 2 lines

a2dp headsets are required to support 44.1khz btw.

Mhh damn, this can be the cause. They are supposed to support 22-24kHz.

Again, if I use windows with Widcomm I get a very high rate, it must be about 22 khz. If I use the usb-dongle that comes with it, I get a very good rate, under linux or windows.

I will try again, and see if I can improve it.

Thanks,
Manuel.

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#3 lore raw

Hi,
Can you send us the output of the dameon and your .a2dprc file? As usual, which player are you using?
Thanks,
Frederic.

-------- Message d'origine--------
De: [email protected] de la part de Naranjo Manuel Francisco
Date: mer. 15/11/2006 22:39
À: BlueZ users
Objet : Re: [Bluez-users] Low quality audio on Bluetooth Headset

Quoted 4 lines

what kind of quality problem? Is it only the low sampling rate or is it one of the other problems? (low volume... popping sounds... played too fast or slow... static...)

Very low sampling rate, it must be working about 10kHz. And I also get disconnection problems, but this can be due to problems on my usb connectors, they aren't working very well lately.

Quoted 2 lines

a2dp headsets are required to support 44.1khz btw.

Mhh damn, this can be the cause. They are supposed to support 22-24kHz.

Again, if I use windows with Widcomm I get a very high rate, it must be about 22 khz. If I use the usb-dongle that comes with it, I get a very good rate, under linux or windows.

I will try again, and see if I can improve it.

Thanks,
Manuel.

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#4 lore raw

Frederic Dalleau escribi=F3:

Quoted 5 lines

Hi,
Can you send us the output of the dameon and your .a2dprc file? As usual, which player are you using?
Thanks,
Frederic

Hi,
At the end you can find the output. I think I have a clue why I get so =

low audio quality, I think that a2dpd is connecting to the hands free =

channel instead of the hifi channel (check the sdpbrowse tools at the =

end). Is there anyway I can select to which channel a2dpd connects? Cheers,
Manuel

OUTPUT FROM a2dpd:
Cannot open /dev/input/uinput: No such file or directory a2dpd [Nov 8 2006 10:26:52] starting ...a2dpd addr=3D00:12:0E:06:C5:8A =

timer=3D4000 us [Nov 8 2006 10:26:52]
setscheduler returns -1 (errno=3D1:Operation not permitted) main_thread:Accepting incoming tcp stream connection
New connection to bluetooth [44100 hz]
avrcp: Accepting incoming connection
avdtp: Accepting incoming connection
main_thread: Accepted 5
PCM thread 0.5 started
[1] Receiving failed on socket 0.5 error (0/4 bytes) errno=3D0:Success Client thread 0.5 ending: error
main_thread:Accepting incoming tcp stream connection
main_thread: Accepted 5
PCM thread 0.5 started
[1] Receiving failed on socket 0.5 error (0/4 bytes) errno=3D0:Success Client thread 0.5 ending: error
main_thread:Accepting incoming tcp stream connection
main_thread: Accepted 5
PCM thread 0.5 started
main_thread:Accepting incoming tcp stream connection
[1] Receiving failed on socket 0.5 error (-1/4 bytes) errno=3D11:Resource =

temporarily unavailable
Client thread 0.5 ending: timeout
main_thread: Accepted 10
PCM thread 0.10 started
DEBUG: a2dp_new: 00:12:0E:06:C5:8A, 44100 main_thread:Accepting incoming tcp stream connection
DEBUG: detect_a2dp: Found A2DP Sink
DEBUG: connect_stream: Found A2DP Sink at the destination (psm_cmd=3D25)
DEBUG: connect_stream: Sent the Stream End Point Discovery Command
DEBUG: a2dp_handle_avdtp_message: Read non command packet =

(msgtype=3D2,signal=3D1)
DEBUG: connect_stream: Got a Stream End Point Discovery (4 bytes) =

Response (msgtype=3D2,pkttype=3D0,lbl=3D0,sig=3D1,rfa=3D0) 02010408
DEBUG: connect_stream: received 1 capabilities
DEBUG: process_seid: Got capabilities response:
servcap_cap=3D1, servcap_len=3D0,
cap_type=3D7, length=3D6, media_type=3D0, codec=3D0
avrcp: socket 7: Connection from 8A:C5:06:0E:12:00, mtu=3D672
avrcp: socket 7: Reading from 8A:C5:06:0E:12:00, mtu=3D672
DEBUG: process_seid: Got Set Configurations Response (2 =

bytes:msgtype=3D2,pkttype=3D0,lbl=3D2,sig=3D3,rfa=3D0)
DEBUG: connect_stream: Sent stream start(seid=3D1)
DEBUG: connect_stream: Got start stream confirm
DEBUG: listen_thread: Listen thread running [control_sk=3D5]
avrcp: socket 7: Reading from 8A:C5:06:0E:12:00, mtu=3D672
avrcp: socket 7: Reading from 8A:C5:06:0E:12:00, mtu=3D672
avrcp: socket 7: Reading from 8A:C5:06:0E:12:00, mtu=3D672
avrcp: socket 7: Reading from 8A:C5:06:0E:12:00, mtu=3D672
avrcp: socket 7: Reading from 8A:C5:06:0E:12:00, mtu=3D672
avrcp: socket 7: Reading from 8A:C5:06:0E:12:00, mtu=3D672
avrcp: socket 7: Reading from 8A:C5:06:0E:12:00, mtu=3D672
avrcp: socket 7: Reading from 8A:C5:06:0E:12:00, mtu=3D672
avrcp: socket 7: Reading from 8A:C5:06:0E:12:00, mtu=3D672
avrcp: socket 7: Reading from 8A:C5:06:0E:12:00, mtu=3D672
avrcp: socket 7: Reading from 8A:C5:06:0E:12:00, mtu=3D672
avrcp: socket 7: Reading from 8A:C5:06:0E:12:00, mtu=3D672
avrcp: socket 7: Reading from 8A:C5:06:0E:12:00, mtu=3D672
avrcp: socket 7: Reading from 8A:C5:06:0E:12:00, mtu=3D672
avrcp: socket 7: Reading from 8A:C5:06:0E:12:00, mtu=3D672
avrcp: socket 7: Reading from 8A:C5:06:0E:12:00, mtu=3D672
avrcp: socket 7: Reading from 8A:C5:06:0E:12:00, mtu=3D672
avrcp: socket 7: Reading from 8A:C5:06:0E:12:00, mtu=3D672
avrcp: socket 7: Reading from 8A:C5:06:0E:12:00, mtu=3D672
avrcp: socket 7: Reading from 8A:C5:06:0E:12:00, mtu=3D672
avrcp: socket 7: Reading from 8A:C5:06:0E:12:00, mtu=3D672
avrcp: socket 7: Reading from 8A:C5:06:0E:12:00, mtu=3D672
avrcp: socket 7: Reading from 8A:C5:06:0E:12:00, mtu=3D672
avrcp: socket 7: Reading from 8A:C5:06:0E:12:00, mtu=3D672
avrcp: socket 7: Reading from 8A:C5:06:0E:12:00, mtu=3D672
avrcp: socket 7: Reading from 8A:C5:06:0E:12:00, mtu=3D672
avrcp: socket 7: Reading from 8A:C5:06:0E:12:00, mtu=3D672
avrcp: socket 7: Reading from 8A:C5:06:0E:12:00, mtu=3D672
avrcp: socket 7: Reading from 8A:C5:06:0E:12:00, mtu=3D672
avrcp: socket 7: Reading from 8A:C5:06:0E:12:00, mtu=3D672 handling SIGINT
main_thread: Accepted 11
Destroying lpA2dp, end of loop
DEBUG: a2dp_destroy: Begin
DEBUG: a2dp_free:
DEBUG: a2dp_destroy: a2dp_destroy(0x8058460) OK Client thread 0.10 ending: no error
A2DPD still 2 clients running
socket 7: Receive failed 0 (error 0:Success)
avrcp: socket 7: timed out
A2DPD still 2 clients running
A2DPD terminated succesfully
----- END OF OUTPUT

sdpbrowse results :
Service Name: Audio Sink
Service RecHandle: 0x110b
Service Class ID List:
"Audio Sink" (0x110b)
Protocol Descriptor List:
"L2CAP" (0x0100)

    PSM: 25
  "AVDTP" (0x0019)
    uint16: 0x100

Language Base Attr List:
code_ISO639: 0x656e
encoding: 0x6a
base_offset: 0x100
Profile Descriptor List:
"Advanced Audio" (0x110d)

    Version: 0x0100

Service Name: Headset
Service RecHandle: 0x1108
Service Class ID List:
"Headset" (0x1108)
"Generic Audio" (0x1203)
Protocol Descriptor List:
"L2CAP" (0x0100)
"RFCOMM" (0x0003)
Channel: 8
Language Base Attr List:
code_ISO639: 0x656e
encoding: 0x6a
base_offset: 0x100
Profile Descriptor List:
"Headset" (0x1108)

    Version: 0x0100

Service Name: Handsfree
Service RecHandle: 0x111e
Service Class ID List:
"Handsfree" (0x111e)
"Generic Audio" (0x1203)
Protocol Descriptor List:
"L2CAP" (0x0100)
"RFCOMM" (0x0003)
Channel: 7
Language Base Attr List:
code_ISO639: 0x656e
encoding: 0x6a
base_offset: 0x100
Profile Descriptor List:
"Handsfree" (0x111e)

    Version: 0x0101

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VDEV
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