Audio over Stereo Connectors


#1

The release notes of the latest software say:

New Features in this release (CAF tag: LA.BR.1.2.4-01810-8x16.0) compared to June release (Caf tag: LA.BR.1.2.4-00310-8x16-1)

Audio over Stereo connectors
Needs stereo connector soldered to J7 and mixer settings changed in SW

I understand the connections on J7 from the documentation and schematic, but how do I change the mixer settings in the software? I have been tracing through the source code but I’m hoping someone can give me a pointer.


#2

I copied the headphones settings into the hdmi sections of mixer_paths_sbc.xml and got audio out on my headphones…but it sounded a bit crackly and then the TV turned blue and the sound got stuck. I had to power cycle the board.


#3

I reverted the mixer_paths_sbc.xml file and instead change the audio_policy.conf to set

default_output_device AUDIO_DEVICE_OUT_WIRED_HEADPHONE

I now get full volume audio on the headphones for a few seconds, although it is crackly, and then it drops dramatically so that I can barely hear it, even at full volume.


#4

Hi,
I tried also to change the audio_policy.conf but I get read only error:

sudo adb -s b6ca2e78 push audio_policy.conf /system/etc/audio_policy.conf
adb server is out of date.  killing...
* daemon started successfully *
failed to copy 'audio_policy.conf' to '/system/etc/audio_policy.conf': Read-only file system

#5

I haven’t had a chance to test this, but the Audio App note here https://developer.qualcomm.com/download/db410c/stereo-connector-and-audio-routing-application-note.pdf gives some direction on how to route audio to the headset jack under Android by using tinymix commands. Have you tried tinymix yet?