Enabling USB headset on android running on OMAP3EVM

USB Audio is not supported with TI Android DevKit. However you might be able to use it by modifying the ALSA HAL, since as per your logs the device is supported in the kernel.

You can refer to the porting guides for more information http://processors.wiki.ti.com/index.php/TI-Android-GingerBread-2.3.4-DevKit-2.1_PortingGuides#Audio

Hi Vishveshwar,

  Thanks for reply.

I have tried line-in and line-out headset jack its speakers were working fine I was able to listen audio.Since microphone was  (non-preamplified) input so it was not recording sound directly.Thats why i want to enable usb headset.

I have referred the link that you have given http://processors.wiki.ti.com/index.php/TI-Android-GingerBread-2.3.4-DevKit-2.1_PortingGuides#Audio .

This link says hardware for default out device is hw 0:0 whereas BT SCO device is hw 0:1  and after looking following logs 

# alsa_aplay -l
**** List of PLAYBACK Hardware Devices ****
card 0: omap3evm [omap3evm], device 0: TWL4030 twl4030-hifi-0 []
Subdevices: 1/1
Subdevice #0: subdevice #0
card 0: omap3evm [omap3evm], device 1: WL1271BT wl1271bt-1 []
Subdevices: 1/1
Subdevice #0: subdevice #0
card 1: default [C-Media USB Headphone Set ], device 0: USB Audio [USB Audio]
Subdevices: 1/1
Subdevice #0: subdevice #0
#

It seems that hardware for my usb headset will be hw 1:0 (card 1,device 0). So I changed  

ALSAControl control("hw:00");
to

ALSAControl control("hw:10"); in alsa_module.cpp file and after rebuilding I have replaced alsa.omap3evm.so. 

But still there no sound is coming from usb headset on playing an audio file on mediaplayer or on commandline.

1. Do I need to change something else ? or 

2. Do I have to create new handle for usb headphone in alsa_handle_t _defaults[] ,if yes, then what will be the buffer size for usb headphone as it is  bufferSize  : DEFAULT_SAMPLE_RATE / 5 for OMAP3_OUT_SCO and bufferSize  : DEFAULT_SAMPLE_RATE / 11, for OMAP3_OUT_DEFAULT ?

Please help.

 alsa_handle_t _defaults[]

Hi,

One more thing I have tried "alsa_arecord -v -f cd | alsa_aplay -v" command to know the parameters during  the usb headset attached.

output of above command is :

# alsa_arecord -v -f cd | alsa_aplay -v
Recording WAVE 'stdin' : Signed 16 bit Little Endian, Rate 44100 Hz, Stereo
Plug PCM: Hardware PCM card 0 'omap3evm' device 0 subdevice 0
Its setup is:
stream : CAPTURE
access : RW_INTERLEAVED
format : S16_LE
subformat : STD
channels : 2
rate : 44100
exact rate : 44100 (44100/1)
msbits : 16
buffer_size : 27560
period_size : 5512
period_time : 124988
tstamp_mode : NONE
period_step : 1
avail_min : 5512
period_event : 0
start_threshold : 1
stop_threshold : 27560
silence_threshold: 0
silence_size : 0
boundary : 1806172160
Playing WAVE 'stdin' : Signed 16 bit Little Endian, Rate 44100 Hz, Stereo
Plug PCM: Hardware PCM card 0 'omap3evm' device 0 subdevice 0
Its setup is:
stream : PLAYBACK
access : RW_INTERLEAVED
format : S16_LE
subformat : STD
channels : 2
rate : 44100
exact rate : 44100 (44100/1)
msbits : 16
buffer_size : 27560
period_size : 5512
period_time : 124988
tstamp_mode : NONE
period_step : 1
avail_min : 5512
period_event : 0
start_threshold : 27560
stop_threshold : 27560
silence_threshold: 0
silence_size : 0
boundary : 1806172160
^Z[1] + Stopped alsa_arecord -v -f cd | alsa_aplay -v

the bold lines in this output are showing pluged hardware is card 0 'omap3evm' device 0 

while the output of alsa_aplay shows default device is 

card 1: default [C-Media USB Headphone Set ], device 0: USB Audio [USB Audio]
Subdevices: 1/1
Subdevice #0: subdevice #0

then why omap3evm is being used for playing?

and how to change it to  usb headphone (card 1, device 0) ?

Thanks in advance for your reply.

Regards

Govind Singh Parmar