[opus] Using opus on ATMEL 32-bit RISC microcontroller

Daniele Barzotti daniele.barzotti at eurocomtel.com
Fri Aug 26 16:40:50 UTC 2016

Hi all,

thanks a lot for your replies!

Sorry for my typo, the flash size is 8MB (Byte) :-)
Unfortunately I cannot use another flash because I'm working on a 
proprietary board.

Jean-Marc, thanks for your suggestions.
I thought to use fixed point for convenience, but I can work on floating 
point too, so I will take in account the codec2 (I didn't know it).

Moreover, if you all have other suggestions to give me I appreciate! ;-)


Il 2016-08-26 18:12 Amit Ashara ha scritto:
> Hello Daniele
> It would be worthwhile to attach an external serial flash or USB thumb
> drive, if the intent is store data. This allows for far more
> flexibility in storage
> Regards
> Amit
> On Fri, Aug 26, 2016 at 11:02 AM, Jean-Marc Valin <jmvalin at jmvalin.ca>
> wrote:
>> On 26/08/16 11:40 AM, Daniele Barzotti wrote:
>>> You're right! I forgot to say that I need only the encoder side
>> (and
>>> only for voice).
>> Then you can remove all of the decoder. As for the encoder, it
>> depends
>> on the bitrate and sampling rate you want (more below).
>>> My application have to acquire a 16bit 8KHz PCM stream and save a
>>> compressed audio into a flash.
>> Sounds like a job for SILK-only mode. In which case you can strip
>> away
>> all of CELT.
>>> (And here I have another little question...
>>> My flash size is 8Mb only and I have to be able to store in it 8
>> hours
>>> of voice, do you think opus shrink the stream enoguht?)
>> This is going to be a problem. Assuming you mean 8 mega*byte* (and
>> not 8
>> megabit), that's still only 2 kilobit/second. Opus pretty much
>> requires
>> 8 kb/s, so 4 times what you have. The only codec I know that can do
>> 2
>> kb/s with reasonable quality is codec2, and the implementation is
>> floating point.
>>> Since I'm using FIXED_POINT, I have to pass also
>> --disable-float-api?
>> Yes. The normal API has calls with both int and float, so if you
>> compile
>> with FIXED_POINT, the float calls do a conversion to int before
>> using
>> int internally. If you disable the float API, these functions are
>> not
>> compiled at all, saving a few bytes.
>> Cheers,
>> Jean-Marc
>> _______________________________________________
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>> opus at xiph.org
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