Re: [alsa-devel] [Linux-kernel] [PATCH v5 2/7] ASoC: tegra: Allow 24bit and 32bit samples

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On 24/01/2020 16:50, Jon Hunter wrote:

On 23/01/2020 19:38, Ben Dooks wrote:
On 07/01/2020 01:39, Dmitry Osipenko wrote:
06.01.2020 22:00, Ben Dooks пишет:
On 05/01/2020 10:53, Ben Dooks wrote:


On 2020-01-05 01:48, Dmitry Osipenko wrote:
05.01.2020 03:04, Ben Dooks пишет:
[snip]

I've just gone through testing.

Some simple data tests show 16 and 32-bits work.

The 24 bit case seems to be weird, it looks like the 24-bit expects
24 bit samples in 32 bit words. I can't see any packing options to
do 24 bit in 24 bit, so we may have to remove 24 bit sample support
(which is a shame)

My preference is to remove the 24-bit support and keep the 32 bit in.


Interesting.. Jon, could you please confirm that 24bit format isn't
usable on T30?

If there is an option of 24 packed into 32, then I think that would
work.

I can try testing that with raw data on Monday.

I need to check some things, I assumed 24 was 24 packed bits, it looks
like the default is 24 in 32 bits so we may be ok. However I need to
re-write my test case which assumed it was 24bits in 3 bytes (S24_3LE).

I'll follow up later,

Okay, the S24_3LE isn't supported by RT5640 codec in my case. I briefly
looked through the TRM doc and got impression that AHUB could re-pack
data stream into something that codec supports, but maybe it's a wrong
impression.
_________________________________

I did a quick test with the following:

  sox -n -b 16 -c 2 -r 44100 /tmp/tmp.wav  synth sine 500 vol 0.5
  sox -n -b 24 -c 2 -r 44100 /tmp/tmp.wav  synth sine 500 vol 0.5
  sox -n -b 32 -c 2 -r 44100 /tmp/tmp.wav  synth sine 500 vol 0.5

The 16 and 32 work fine, the 24 is showing a playback output freq
of 440Hz instead of 500Hz... this suggests the clock is off, or there
is something else weird going on...

I was looking at using sox to create such as file, but the above command
generates a S24_3LE file and not S24_LE file. The codec on Jetson-TK1
supports S24_LE but does not support S24_3LE and so I cannot test this.
Anyway, we really need to test S24_LE and not S24_3LE because this is
the problem that Dmitry is having.

Ben is S24_3LE what you really need to support?

No, it is S24_LE the format this hardware supports. I wonder if
aplay is transforming it.

Plug PCM: Linear conversion PCM (S24_LE)
Its setup is:
  stream       : PLAYBACK
  access       : RW_INTERLEAVED
  format       : S24_3LE
  subformat    : STD
  channels     : 2

So I assume aplay has turned the S24_3LE -> S24_LE



--
Ben Dooks				http://www.codethink.co.uk/
Senior Engineer				Codethink - Providing Genius

https://www.codethink.co.uk/privacy.html



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