Bluetooth audio local-echo

[sergio_dorazio]

Hi,

I am working with imx6ull-evk with a bluetooth board . I use bluez and HSP profile . When I connect a smartphone(TEL0) over bluetooth, tha board imx6 is the audio interface of the smarphone. When I do a call from an other telephone (TEL1), I can speak on imx6ull-evk microphone and listen on TEL1 , and I can speak on TEL1 and listen on imx6ull-evk headset. Seems all work but in this configuration I have a little think that not work well: when I speak from TEL1 , I listen on TEL1 the local-echo of my voice. This local-echo have a latency of about 1 second at init call but increase over time. 

Have you an idea about this problem ?

Sergio

[diegoadrian]

Hello,

What Bluetooth chip are you using?

Best regards,

Diego.

[sergio_dorazio]

Hi Diego,

I am using texas CC2564.

Regards,

Sergio.

[diegoadrian]

Hello,

Could you please tell in which audio profile are you configuring the virtual audio Bluetooth card?

Is in a2dp or hsp?

Best regards,

Diego.

[sergio_dorazio]

I Diego,

I have hsp profile , I send you my "sdptool browse local" result:

root@imx6ull14x14evk:~# sdptool browse local
Browsing FF:FF:FF:00:00:00 ...
Service RecHandle: 0x10000
Service Class ID List:
  "PnP Information" (0x1200)
Profile Descriptor List:
  "PnP Information" (0x1200)
    Version: 0x0103

Browsing FF:FF:FF:00:00:00 ...
Service Search failed: Invalid argument
Service Name: Serial Port
Service Description: COM Port
Service Provider: BlueZ
Service RecHandle: 0x10001
Service Class ID List:
  "Serial Port" (0x1101)
Protocol Descriptor List:
  "L2CAP" (0x0100)
  "RFCOMM" (0x0003)
    Channel: 1
Language Base Attr List:
  code_ISO639: 0x656e
  encoding:    0x6a
  base_offset: 0x100
Profile Descriptor List:
  "Serial Port" (0x1101)
    Version: 0x0100

Service Name: Network Access Point Service
Service RecHandle: 0x10002
Service Class ID List:
  "Network Access Point" (0x1116)
Protocol Descriptor List:
  "L2CAP" (0x0100)
    PSM: 15
  "BNEP" (0x000f)
    Version: 0x0100
    SEQ16: 10 20 30 40
Profile Descriptor List:
  "Network Access Point" (0x1116)
    Version: 0x0100

Service Name: hfp_hf
Service RecHandle: 0x10003
Service Class ID List:
  "Handsfree" (0x111e)
  "Generic Audio" (0x1203)
Protocol Descriptor List:
  "L2CAP" (0x0100)
  "RFCOMM" (0x0003)
    Channel: 7
Profile Descriptor List:
  "Handsfree" (0x111e)
    Version: 0x0107

Service Name: Network service
Service Description: Network service
Service RecHandle: 0x10004
Service Class ID List:
  "Network Access Point" (0x1116)
Protocol Descriptor List:
  "L2CAP" (0x0100)
    PSM: 15
  "BNEP" (0x000f)
    Version: 0x0100
    SEQ16: 800 806
Language Base Attr List:
  code_ISO639: 0x656e
  encoding:    0x6a
  base_offset: 0x100
Profile Descriptor List:
  "Network Access Point" (0x1116)
    Version: 0x0100

Service Name: Headset Voice gateway
Service RecHandle: 0x10007
Service Class ID List:
  "Headset Audio Gateway" (0x1112)
  "Generic Audio" (0x1203)
Protocol Descriptor List:
  "L2CAP" (0x0100)
  "RFCOMM" (0x0003)
    Channel: 12
Profile Descriptor List:
  "Headset" (0x1108)
    Version: 0x0102

root@imx6ull14x14evk:~#

Sergio

[diegoadrian]

Hello,

Could you please try modifying the /etc/pulse/daemon.conf file as below and restart the pulseaudio service:

; log-backtrace = 0

resample-method = trivial

enable-remixing = no

enable-lfe-remixing = no

; flat-volumes = no

; rlimit-fsize = -1

This will lower the sound resolution. But it could solve some sound latency problems.

Best regards,

Diego.

[sergio_dorazio]

Hi Diego,

with your modifications I have the same problem...

Have you other suggestions ?

Sergio.

[diegoadrian]

Hello,

Could you please try the following:

pactl set-card-profile $BLUEZCARD hsp
pactl set-card-profile $BLUEZCARD a2dp 
pactl set-card-profile $BLUEZCARD hsp‍‍‍

Best regards,

Diego.

[sergio_dorazio]

Hi Diego ,

when I connect bluetooth I have the following pulseaudio cards:

root@RCA2:~# pactl list cards
Card #0
Name: alsa_card.platform-sound
Driver: module-alsa-card.c
Owner Module: 6
Properties:
alsa.card = "0"
alsa.card_name = "wm8960-audio"
alsa.long_card_name = "wm8960-audio"
device.bus_path = "platform-sound"
sysfs.path = "/devices/soc0/sound/sound/card0"
device.form_factor = "internal"
device.string = "0"
device.description = "Built-in Audio"
module-udev-detect.discovered = "1"
device.icon_name = "audio-card"
Profiles:
input:analog-mono: Analog Mono Input (sinks: 0, sources: 1, priority: 2, available: yes)
output:analog-mono: Analog Mono Output (sinks: 1, sources: 0, priority: 200, available: yes)
output:analog-mono+input:analog-mono: Analog Mono Duplex (sinks: 1, sources: 1, priority: 202,
available: yes)
off: Off (sinks: 0, sources: 0, priority: 0, available: yes)
Active Profile: output:analog-mono+input:analog-mono
Ports:
analog-input: Analog Input (priority: 10000, latency offset: 0 usec)
Part of profile(s): input:analog-mono, output:analog-mono+input:analog-mono
analog-output-speaker: Speakers (priority: 10000, latency offset: 0 usec, not available)
Properties:
device.icon_name = "audio-speakers"
Part of profile(s): output:analog-mono, output:analog-mono+input:analog-mono
analog-output-headphones: Headphones (priority: 9000, latency offset: 0 usec, available)
Properties:
device.icon_name = "audio-headphones"
Part of profile(s): output:analog-mono, output:analog-mono+input:analog-mono

Card #1
Name: bluez_card.BC_A5_8B_A3_8C_3A
Driver: module-bluez5-device.c
Owner Module: 20
Properties:
device.description = "SDO Galaxy J6"
device.string = "BC:A5:8B:A3:8C:3A"
device.api = "bluez"
device.class = "sound"
device.bus = "bluetooth"
device.form_factor = "phone"
bluez.path = "/org/bluez/hci0/dev_BC_A5_8B_A3_8C_3A"
bluez.class = "0x5a020c"
bluez.alias = "SDO Galaxy J6"
device.icon_name = "audio-card-bluetooth"
Profiles:
a2dp_source: High Fidelity Capture (A2DP Source) (sinks: 0, sources: 1, priority: 10, availabl
e: no)
headset_audio_gateway: Headset Audio Gateway (HSP/HFP) (sinks: 1, sources: 1, priority: 20, av
ailable: yes)
off: Off (sinks: 0, sources: 0, priority: 0, available: yes)
Active Profile: headset_audio_gateway
Ports:
phone-output: Phone (priority: 0, latency offset: 0 usec)
Part of profile(s): headset_audio_gateway
phone-input: Phone (priority: 0, latency offset: 0 usec)
Part of profile(s): a2dp_source, headset_audio_gateway

I can do the following command :

root@RCA2:~#
root@RCA2:~# pactl set-card-profile 1 headset_audio_gateway
root@RCA2:~#

root@RCA2:~# pactl set-card-profile 1 a2dp_source
Failure: Input/Output error

root@RCA2:~#

In my test I want hsp/hfp profile and not a2dp profile.

In any case the result is the same : I have the audio local-echo on TEL1.

Have you other suggestion ?

Sergio.

[diegoadrian]

Hello,

Could you please try adding the echo cancelation module by yourself? Please modify the following file:

/etc/pulse/default.pa
### Enable Echo/Noise-Cancellation
load-module module-echo-cancel use_master_format=1 aec_method=webrtc aec_args="analog_gain_control=0\ digital_gain_control=1" source_name=echoCancel_source sink_name=echoCancel_sink
set-default-source echoCancel_source
set-default-sink echoCancel_sink‍‍‍‍‍‍‍‍‍‍

then restart Pulseaudio

$ pulseaudio -k
$ pulseaudio --start
‍‍

Hope this can solve the problem.

Best regards,

Diego.

[sergio_dorazio]

I Diego,

I found the problem:

when pulse audio see a bluetooth connection load a module loopback from analog card to bluetooth card. This loopback not work well because work only in a single way and not in both way (I need both way). In this situation if I add other loopback module , the loop work in both way but there is the  local-echo. If I unload the module loopback of pulseaudio but not remove my loopback module the local-echo disappear  and the loopback from bluetooth card and analog card work well.

By

thank you for all.

Sergio D'Orazio.