[alsa-devel] Support for DSD streams

[Daniel Mack]

Hi Andreas,

On 23.03.2013 18:35, Andreas Koch wrote:
>> Yes, understood. The thing is just that we shouldn't break exising
>> solutions that already rely on this "bandaid".
> 
> You wouldn't break any existing solution based on DoP, because that 
> solution is dealt with in the application on one side and the DAC on 
> the other side. The driver and USB transfer both think it is PCM data 
> that is being sent.

Well, that was exactly the problem with your device. With the driver as
it was, it exposed a PCM interface which is 16-bit wide, and that was
picked by ALSA when playing 16-bit material (because ALSA takes whatever
is offered by the hardware natively).

> The applications have a preference setting to 
> select DoP and likewise the DAC's constantly monitor the PCM 
> formatted data stream and automatically switch to DSD if they find 
> the pattern. 

Hmm, but your device behaves differently here, right? At least, when
normal PCM material is sent to the DSD interface, it doesn't play it or
switch back or something. And I think other DACs will have similar
behaviour.

I need to think about all that more deeply next week :)


Daniel