[alsa-devel] [RFC][PATCH 00/15 v4] OXFW driver, a succesor to firewire-speakers

[Takashi Sakamoto]

On Aug 13 2014 16:06, Clemens Ladisch wrote:
> When I wrote the driver, Jay tested which combinations did actually
> work (without any stream format information command; I don't have the
> spec), so that's what the driver ended up supporting:
>  - 6ch at 32/44.1/48/96 kHz
>  - 2ch at 48/96 kHz
> 
> If snd-oxfw also does not send the stream format information command,
> then I guess that 2ch at 32/44.1 kHz will not work either.

If so, Jey's test included something wrong. I hope someone to test these
combinations again, especially 2ch/96kHz.

>> [...]
>> Instead, we should consider the 2ch modes. This mode seems to be used
>> for Dolby Pro Logic II and Dolby Digital but I don't know about the
>> specification of Dolby something. If we drop these modes, the work to
>> develop OXFW driver becomes simpler.
> 
> The driver does not need care about the format itself; the data is just
> sent as 16-bit words that pretend to be samples.  All the driver has to
> do is to handle the "non-audio" bit in the "IEC958 Playback Default" or
> "IEC958 Playback PCM Stream" mixer controls; this can be added later.

Hm. So the driver just transfers 2ch 16bit words in IEC 60958 compliant
data channels, then the device handles them for surround channels. I
misunderstand that Dolby something is a functionality in driver side.


Regards

Takashi Sakamoto
(In summer vacation)
o-takashi at sakamocchi.jp