On Wed, Aug 2, 2023 at 7:22 PM Takashi Iwai [off-list ref] wrote:

On Wed, 02 Aug 2023 09:32:37 +0200,
Hans Verkuil wrote:

quoted

Hi all,

On 25/07/2023 08:12, Shengjiu Wang wrote:

quoted

Audio signal processing has the requirement for memory to
memory similar as Video.

This patch is to add this support in v4l2 framework, defined
new buffer type V4L2_BUF_TYPE_AUDIO_CAPTURE and
V4L2_BUF_TYPE_AUDIO_OUTPUT, defined new format v4l2_audio_format
for audio case usage.

The created audio device is named "/dev/audioX".

And add memory to memory support for two kinds of i.MX ASRC
module

Before I spend time on this: are the audio maintainers OK with doing
this in V4L2?

I do want to have a clear statement on this as it is not something I
can decide.

Well, I personally don't mind to have some audio capability in v4l2
layer.  But, the only uncertain thing for now is whether this is a
must-have or not.

Thanks,  I am also not sure about this.  I am also confused that why
there is no m2m implementation for audio in the kernel.  Audio also
has similar decoder encoder post-processing as video.

IIRC, the implementation in the sound driver side was never done just
because there was no similar implementation?  If so, and if the
extension to the v4l2 core layer is needed, shouldn't it be more
considered for the possible other route?

Actually I'd like someone could point me to the other route. I'd like to
try.

The reason why I select to extend v4l2 for such audio usage is that v4l2
looks best for this audio m2m implementation.  v4l2 is designed for m2m
usage.  if we need implement another 'route',  I don't think it can do better
that v4l2.

I appreciate that someone can share his ideas or doable solutions.
And please don't ignore my request, ignore my patch.

Best regards
Wang shengjiu