2009-09-28 15:46:07     best multi-channel audio chip for alsa

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2009-09-28 15:46:07     best multi-channel audio chip for alsa

Ron Weiland (UNITED STATES)

Message: 80584   

 

With Analog Devices obsoleting the AD1980, I have to redesign our hardware for a new audio chip.  Right now I am using a highly modified version of the snd-ad1980 driver to get three separate 8k -> 48k mono resampled input / output  channels, and my application talks directly with the driver.   Along with the redesign, I'm using 2009 release and ALSA.

 

What audio chips do you feel currently have the best driver support for my needs?

 

Thanks!

 

Ron Weiland

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2009-09-28 16:05:09     Re: best multi-channel audio chip for alsa

Robin Getz (UNITED STATES)

Message: 80586   

 

Ron:

 

How many channels of input/output and what sample rates do you need to support?

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2009-09-28 16:21:14     Re: best multi-channel audio chip for alsa

Ron Weiland (UNITED STATES)

Message: 80588   

 

Hi Robin, thanks for responding.

 

Two independent input / output channels (mono) is minimum, three preferred.  For sample rates I mostly use 8k (PA, walkie-talkie), but need everything from 8k to 44.1k (and back), although I could probably get by limiting it to 32k. In the existing code, I put my own resampling in the snd-ad1980 driver.  We don't need stereo anywhere.

 

Ron

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2009-10-06 16:20:19     Re: best multi-channel audio chip for alsa

Ron Weiland (UNITED STATES)

Message: 80911    Would anyone like to chime in on *their* experiences with alsa / sound

chips / 2009 release?

 

Thanks!

Ron Weiland

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2009-10-06 16:32:14     Re: best multi-channel audio chip for alsa

Robin Getz (UNITED STATES)

Message: 80912   

 

Ron:

 

Sorry for the delay - I read this, and forgot to respond. My bad.

 

When you say "need everything from 8k to 44.1k" - do you mean standard? (8, 16, 32, 44.1, 48) - or at what resolution do you mean? While the AD1980 had a very flexible SRC on it - most other codecs only support one or two sample rates, and software SRC does the rest.

 

-Robin

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2009-10-06 17:02:15     Re: best multi-channel audio chip for alsa

Ron Weiland (UNITED STATES)

Message: 80913    No problem Robin. Don't know how you guys keep up with it as it is!

 

Yes, I mean "standard" rates. The ones I support now are: 8K, 11.025K,

16K, 22.050K, 32K, 44.1K, and 48K. While in theory the AD1980 supports

variable rates, in reality it only works properly at 48K with the

Slot-16 AFIK. I currently do all the sample rate conversions

(interpolated) in my driver. I don't actually know where the SRC is done

in alsa, if it is there at all. (My job to figure *that* out.)

 

My main concern is that for the redesign, I choose an audio chip /

driver combo that will work well with the alsa. I know that just

because a driver exists, doesn't mean all the features are fully

implemented.

 

In a nutshell, my requirements are this:

 

Two or more mono (or stereo with L/R treated as separate) output

channels at different sample rates,

Two or more separate mono input channels at different sample rates,

Alsa works well with it,

Won't go obsolete a year from now (I know you can't promise that!)

 

Thanks again!

Ron Weiland

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2009-10-07 09:39:54     Re: best multi-channel audio chip for alsa

Robin Getz (UNITED STATES)

Message: 80951   

 

Ron:

 

There is a software SRC in the ALSA library - if you are using the OSS - there is none - so it depends on how you are using things in userspace.

 

 

 

There are a few devices - depending on how important 3 DACs are....

 

AD1836A - 4 ADC, 6 DAC, 24-Bit, 96 kHz codec -- it is current output, so you need an external I->V converter (which adds board space).

 

  www.analog.com/en/audiovideo-products/audio-codecs/ad1836a/products/product.html

 

SSM2603 - 2 ADC, 2 DAC, 24-bit, 96 kHz, 88.2 kHz, 48 kHz, 44.1 kHz, 32 kHz, 24 kHz, 22.05 kHz, 16 kHz, 12 kHz, 11.025 kHz, and 8 kHz - standard sample rates -- voltage out, mic pre-amp

 

  www.analog.com/en/audiovideo-products/audio-codecs/ssm2603/products/product.html

 

And only for completeness - we also support chaining for the AD73322 (so you can put down as many as you want).

 

  www.analog.com/en/audiovideo-products/audio-codecs/ad73322l/products/product.html

 

All those are 100% done - and should be close to what you need (we can help make the mono mods to the driver if you want).

 

We are also working on the ADAU1361

 

  www.analog.com/en/audiovideo-products/audio-codecs/adau1361/products/product.html

 

Which should be done in a few weeks, and a new one (no product page, which includes a built in class D amp).

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2009-10-07 20:08:37     Re: best multi-channel audio chip for alsa

Ron Weiland (UNITED STATES)

Message: 80958    Thanks for the great info, Robin.

 

The ADAU1361 looks pretty good, I would like to be able to use the

mixers. Will the driver support multiple chips? Does the SSM2603

driver support multiple chips? (I know the ADI / Arcturus uCBF54x-Start

uses up to 3 SSM2603 chips, but don't know if it is the same driver)

Does it use the same driver as the SSM2602?

 

For background, my company sells to retail chains. We have over 20,000

installations in the field (USA) now that we are slowly replacing with

our Blackfin system, as well as using it for all new installations.

Just started selling overseas as well.

 

Thanks again for your help!

Ron

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2009-10-07 20:30:11     Re: best multi-channel audio chip for alsa

Mike Frysinger (UNITED STATES)

Message: 80959   

 

the arcturus guys have written their own driver as they have simpler needs in terms of audio output

 

currently the Blackfin ASoC framework only supports 1 codec in the system at a time (as the limitation is in the SPORT transport driver), but that's slated to get fixed.

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2009-10-07 22:27:29     Re: best multi-channel audio chip for alsa

Ron Weiland (UNITED STATES)

Message: 80960    Thanks, Mike. Any known timeframe for that?

 

Ron

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2009-10-07 23:18:16     Re: best multi-channel audio chip for alsa

Mike Frysinger (UNITED STATES)

Message: 80961   

 

not currently -- havent heard any direct requests until now.  when we have people actually making requests, things tend to speed up ...

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2009-10-08 09:51:56     Re: best multi-channel audio chip for alsa

Robin Getz (UNITED STATES)

Message: 80973   

 

Ron:

 

When do you need it?

 

-Robin

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2009-10-08 18:59:37     Re: best multi-channel audio chip for alsa

Ron Weiland (UNITED STATES)

Message: 80983    Thanks again, Mike and Robin.

 

As long as I can use the right / left channels as separate 1/2 duplex

streams at different sample rates simultaneously with alsa (that remains

to be seen, I'm new to alsa), I think we would be OK with just one chip.

I would like to make previsions for a second chip "just in case".

Probably the earliest I would need it would be first qtr next year.

 

Ron

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