[alsa-devel] Compressed audio support over HDMI

[Andrej Falout]

> On 11/4/14, 3:40 PM, D K wrote:
> > Hi,
> >     I recently came across the compressed audio framework used with
> ALSA-SOC.
> > Can the framework be used to send compressed audio to HDMI driver?.Like
> > using tinycompress from usespace .
> > thanks,
>
> HDMI already supports IEC modes when you can send AC3, DTS, etc payloads
> without decoding. All you need to do is packetize the data in userspace
> and send the result over the HDMI PCM device (and set some control bits
> to help the receiver lock faster).
>
>

Apologies for jumping in on this subject, I'm wondering if anyone knows if
this method is of sending audio over HDMI is aplocable to DSD streams too?

The reasoning being that once audio is compressed, and encoded (AC3, DTS,
etc), there is not much inherently "PCM" about it. It only becomes PCM
again after it is decoded and uncompressed, right?

In short, it is simply a bitstream, packetized and with "some control bits
set". Which is exactly what I see in HDMI specs in regards to DSD.

So, does anyone know of a reason why this same method wont work for sending
DSD bitstream over HDMI?

Any advice very much appreciated!

Kind regards,
Andrej Falout