On 10/28/2014 04:33 PM, Qais Yousef wrote:
On 10/28/2014 02:54 PM, Lars-Peter Clausen wrote:
On 10/28/2014 02:18 PM, Qais Yousef wrote:
On 10/28/2014 11:55 AM, Clemens Ladisch wrote:
Qais Yousef wrote:
AXD Audio Processing IP performs audio decoding, encoding, mixing,
equalisation,
synchronisation and playback.
What exactly do you mean with "synchronisation" and "playback"?
Synchronisation refers to accurate audio playout relative to a master
clock source including compensation of drift between the master clock
source and the playout clock of the audio hardware. Hence allowing
synchronised audio playout across multiple independent devices.
Playback simple refers to the fact that AXD is capable of managing audio
playout hardware like I2S and SPDIF interfaces.
It doesn't fit in alsa subsystem but I Cced them to confirm.
... because those two words sound like something that a sound card could
do.
The problem mainly stems from the fact that we take a variety of
compressed audio as input and we could perform audio encoding. The
problem with the compressed audio is that the range of decoders and
configuration supported in alsa is limited and there's no support for
taking raw pcm and producing compressed output. I'm not an expert on
alsa but when I looked it looked like there's more infra structure
required.
[...]
This doesn't sound to different from any of the other supported audio
DSPs. ALSA seems to have 95% of what you need. And the missing 5% is
probably stuff that is not specific to your hardware but rather something
that other hardware will need as well. The framework is not set in stone
you can make modifications and add the features that are missing to make
your hardware work.
E.g. look at sound/soc/intel/ for an example of a audio DSP.
No integrating this into ALSA will quite likely result in a quite messy
situation for you on the long run.
- Lars
OK thanks for the reference. To be honest it felt like 15-20% of the
features are missing but I'll need to look at the specifics and
judge/estimate better.
Even then you'd want ALSA integration. You (or your customers) will
eventually want to hook some external devices up to the I2S or SPDIF ports.
All the drivers for the external devices are implemented in ALSA/ASoC.
- Lars
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