* Compressed audio support over HDMI
@ 2014-11-04 21:40 D K
2014-11-05 0:34 ` Pierre-Louis Bossart
0 siblings, 1 reply; 3+ messages in thread
From: D K @ 2014-11-04 21:40 UTC (permalink / raw)
To: alsa-devel; +Cc: vinod.koul
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,
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: Compressed audio support over HDMI
2014-11-04 21:40 Compressed audio support over HDMI D K
@ 2014-11-05 0:34 ` Pierre-Louis Bossart
0 siblings, 0 replies; 3+ messages in thread
From: Pierre-Louis Bossart @ 2014-11-05 0:34 UTC (permalink / raw)
To: D K, alsa-devel; +Cc: vinod.koul
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).
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: Compressed audio support over HDMI
@ 2014-11-13 0:30 Andrej Falout
0 siblings, 0 replies; 3+ messages in thread
From: Andrej Falout @ 2014-11-13 0:30 UTC (permalink / raw)
To: alsa-devel
> 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
^ permalink raw reply [flat|nested] 3+ messages in thread
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2014-11-04 21:40 Compressed audio support over HDMI D K
2014-11-05 0:34 ` Pierre-Louis Bossart
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2014-11-13 0:30 Andrej Falout
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