About I2S 384K output...

andre_chang

I have a lot of 365Khz~384Khz wav & DSD files. When playing the sound I used Pi2 Rune 0.3 is a wonderful.

But I found that these files in the I2S output. The output of 192Khz can only be sad...

Why Pi2 I2S cannot export 384khz? What should I do?

Andre

hondagx35

Hi Andre,

What should I do?

Tell us what DAC is used.

This has nothing to do with RP or RuneAudio.
It all depends on the DAC in use.

The ODROID C1 with hifi shield plays 32/384 without problems.

Frank

andre_chang

Hi Frank：

Thank you for your quick reply ^_^

I used: PI RASPBERRY 2 (B MODEL) + v0.3-beta RUNE (14/04/2015)
& PiFi HIFI DAC+ Digital Audio Card DAC Http://www.dx.com/p/pifi-digi-dac-hifi-digital-audio-card-for-raspberry-pi-b-blue-363003#.VuL43LEm8s9

Config.txt set device_tree_overlay=hifiberry-dac

Play 384Khz WAV is a sound!
But from the oscilloscope to measure the output of 35-PIN LRCK PI2 is only 192Khz

What should I do? (>_<)

Andre

hondagx35

Hi Andre,

what is the output from

cat cat /proc/asound/card*/pcm*p/sub*/hw_params

while playing a 384k file?

You have to adapt this to your needs, by replacing the * with your numbers.

edit:
As far as i know you have to enable the Hifiberry DAC+ driver for your PIFI DAC+.
The Hifiberry DAC+ is only able / rated to play max 192kHz/24bit files.
Ask the manufacturer what driver to use or what to do to get 384kHz working.

Frank

andre_chang

Hi Frank:

I think this is not related to the DAC hifiberry!...
all of the DAC are to receive the digital signal decoding!

I want to know if Pi2 can send 384khz signals from I2S,
I believe that the problem is on the Pi2 & rune!

Because I found that just out Pi2, I2S ananlog also has LRCK digital output.

Again, I have made a comparison between: moode, volumio & rune..
RUNE in I2S LRCK digital output voice is the most balanced!

Andre

hondagx35

Hi Andre,

I want to know if Pi2 can send 384khz signals from I2S,

I did a quick search on the linux kernel sources and it seems you are right.
The Raspberry is limited to 192kHz, but for example ODROID C1 and C2 are capable to play 384kHz.

for Raspberry Pi see here

for ODROID see here
and here.

I believe that the problem is on the Pi2 & rune!

So it seems that linux and not RuneAudio limits the rates.

Frank

andre_chang

Hi Frank:

Thank you for your careful answer, you are too professional!

There is no possibility to increase the Linux's core to allow him to support the 384k output on the Pi2?

In addition, I also found that rune has a strange phenomenon:
When MPD is set to disable DSD, the DSD file can be played smoothly,
If set to DSD enabled, then the player is not running time....
s this correct?

I also found that I2S DSD Pi2 format on the oscilloscope, the output is the DOP format.

Ps.pi2 can not be exported 384khz sad...

Andre

hondagx35

Hi Andre,

andre_chang wroteIn addition, I also found that rune has a strange phenomenon:
When MPD is set to disable DSD, the DSD file can be played smoothly,
If set to DSD enabled, then the player is not running time....
s this correct?

Yes this is the correct behavior.

In the current state DSD works only over USB, because I2S can not handle DSD directly.
With some DACs you only can share the I2S pins for these different technologies.

See also here.

By disabling DSD support mpd resamples / reformats the DSD bitstream to PCM.

Frank

andre_chang

Frank:
Thank you for your time to help me find the answer.

PCM I2s and DSD share a straight line communication. I began to realize that the technology is no problem _ ^ ^
I build a basic DAC AKM4490 chip.
I think he might be the best run of the chip in the hifiberry DAC

But I have a problem right now...
Akm4490 has been able to sing wonderful music, but he has not found in the MPD settings - > output character.
I think it needs power and I2C support, but I don't know what to do....

Andre

Attachments

: dac.jpg (242.58 KiB) Viewed 4742 times