Re: 4a-play on M3

Hello!

I agree that the note on 4a-play isn't clear enough. What it means is that the command does not check if you specify the right role according to the right device.
So if you play something on a PCM (i.e. hw:2,0,0) but specify the wrong role (i.e. navigation which is supposed to be on hw:2,0,1), it means that the wrong role will be opened, preventing others to open the same role.
But you will still play on the specified PCM (hw:2,0,0 in this case).

So nothing to do with USB or not.

The PCM exposed by 4a are streams, handled by the softmixer.
Their ID are hw:X,0,Y, where X is the card number and Y is the stream id.
Usually X=2 because it's the second audio card. But it can depend on the hardware.
4a binds roles to streams, so everything depends on the selected HAL: http://docs.iot.bzh/docs/apis_services/en/dev/reference/audio/high-level-api/TipsAndTricks/HALs.html

On 2018-10-31 06:31, I37546_CHIN@xxxxxxxxxxxxxx wrote:

Hi,

 

I'm using 4a-play to playback WAV files on M3 with ff 6.0.1.

By referring the web documents, I can get sound from a USB headphone,

but nothing from the on-board earphone jack.

 

The Docs say, usually device "hw:2,0,0" matches "multimedia", while I find it also works with "navigation".

Does that mean, "hw:2,0,0" stands for a USB Audio?

And is USB Audio the only device supported currently?

 

Any suggestion appreciated.

 

Thanks

ChenWei

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