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RPi audio trough i2s serial bus - Printable Version

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RPi audio trough i2s serial bus - 0xFF - 2013-05-23

Hello,
I'm new here, sorry if I miss RPi audio related threads.
AFAIK there is only support for noisy analog output and HDMI audio in xbmc.
Recently the ALSA I2S PCM driver for RPi got great improvement: http://blog.koalo.de/2013/05/i2s-support-for-raspberry-pi.html

I connected my DIY NOS DAC, based on TDA1543 chip, to my RPi. It sounds and works great for me.
I'm not familiar with xbmc audio. I don't even know if it need ALSA to work...

Is there chance to have I2S PCM driver in xbmc?

Best regards
Piotr

RE: RPi audio trough i2s serial bus - rikardo1979 - 2013-05-23

would be great to make this working on RPi XBMC distros

RE: RPi audio trough i2s serial bus - nickr - 2013-05-24

XBMC uses alsa.

RE: RPi audio trough i2s serial bus - popcornmix - 2013-05-24

(2013-05-24, 09:35)nickr Wrote: XBMC uses alsa.
No, it doesn't on Pi.
(2013-05-23, 21:56)0xFF Wrote: AFAIK there is only support for noisy analog output and HDMI audio in xbmc.

While the audio from Pi is not great, it shouldn't be noisy.
If it buzzes and growls when the Pi is busy, this noise is caused by the power supply. Can you try with a different power supply?

RE: RPi audio trough i2s serial bus - 0xFF - 2013-05-24

(2013-05-24, 13:16)popcornmix Wrote: While the audio from Pi is not great, it shouldn't be noisy.
If it buzzes and growls when the Pi is busy, this noise is caused by the power supply. Can you try with a different power supply?

Sorry, I meant "noisy"== poor quality ;-)

To be sure xbmc does not depend on ALSA subsystem I unloaded snd-bcm2835 module.
Now I have only one playback device:

Code:
root@malina:/etc# aplay -l
**** List of PLAYBACK Hardware Devices ****
card 0: sndrpitda1541a [snd_rpi_tda1541a], device 0: TDA1541A HiFi tda1541a-hifi-0 []
  Subdevices: 1/1
  Subdevice #0: subdevice #0

But it doesn't matter for xbmc at all.
So, does xbmc on RPi uses its own audio driver?

Best regards
Piotr

RE: RPi audio trough i2s serial bus - popcornmix - 2013-05-24

(2013-05-24, 14:09)0xFF Wrote: But it doesn't matter for xbmc at all.
So, does xbmc on RPi uses its own audio driver?

Yes, it uses OpenMAX for audio and video.

RE: RPi audio trough i2s serial bus - 0xFF - 2013-05-25

I assume OpenMax audio API depends on proprietary GPU binary blob, so there is no chance to extend audio driver to i2s without Broadcom help?

RE: RPi audio trough i2s serial bus - popcornmix - 2013-05-25

(2013-05-25, 13:55)0xFF Wrote: I assume OpenMax audio API depends on proprietary GPU binary blob, so there is no chance to extend audio driver to i2s without Broadcom help?
Correct.
It would be possible to use OpenMax for video only, and ALSA for audio but handling the audio sync is hard.
raspbmc did produce a build that supported this, but it doesn't care about audio sync, so is not suitable for video playback.

RE: RPi audio trough i2s serial bus - 0xFF - 2013-05-25

Thanks for help, I will try Raspbmc.
I would like to use xbmc + RPi as high quality audio files player, so even without audio sync it is still interesting for me.
The best option for me is to have xmbc with OpenMax & ALSA audio support, one for video playback , the other for HQ audio playback.

RE: RPi audio trough i2s serial bus - jeffjoker - 2015-02-19

(2013-05-24, 13:16)popcornmix Wrote: While the audio from Pi is not great, it shouldn't be noisy.
If it buzzes and growls when the Pi is busy, this noise is caused by the power supply. Can you try with a different power supply?

Hello,

I also have this terrible noise.
Constant during anything, playback or just menu.
Gets worse when any action is ongoing (selection from menu, update database...)

Could you precise the link with the power supply ?
Is it random ? Due to insuffisant / too much power ?
I have already tried 3 different power supply and I always have this.

----------------

About the wish for digital audio output, based on previous post, I guess the only solution is to extract it from the HDMI signal ?

Thanks

RE: RPi audio trough i2s serial bus - noggin - 2015-02-19

Suspect something like this : http://www.amazon.co.uk/dp/B00IMGJ5D2/ref=pd_lpo_sbs_dp_ss_2?pf_rd_p=569136327&pf_rd_s=lpo-top-stripe&pf_rd_t=201&pf_rd_i=B008LOIKX6&pf_rd_m=A3P5ROKL5A1OLE&pf_rd_r=08DHN1W0PFF22EPVB0FC might be a solution? Or this : http://www.amazon.co.uk/Sannysis-Converter-Optical-Extractor-Splitter-Black/dp/B00SRE50EM/ref=sr_1_21?s=computers&ie=UTF8&qid=1424345173&sr=1-21&keywords=hdmi+audio+extractor (Looks to be the same but cheaper - though unreviewed...)

I haven't used one but it looks to allow for SPDIF extraction from an HDMI source. Seems to support 2.0 PCM or 5.1 DD/DTS Toslink output? Not cheap in comparison to a Pi, but comparable in price to an I2S solution?