[Speex-dev] lpcSize

Jean-Marc Valin jmvalin at jmvalin.ca
Mon Apr 11 16:18:50 PDT 2011

On 11-04-11 06:48 PM, Shridhar, Vasant wrote:
> Okay,
> Not exactly the answer I was looking for.  This sounds like a big
> change.  I don't mind re-writing the LSP quantizer but re-training
> code books and breaking compatibility is not what I want to do.  I am
> working on an optimization for an ARM cortex-A8.  It is desirable to
> process things in 4 element blocks.  Is there a simpler approach you
> could recommend?

Well, nothing prevents you from simply padding with zeros in the 
functions you're trying to optimize.


> Vasant Shridhar ________________________________________ From:
> Jean-Marc Valin [jmvalin at jmvalin.ca] Sent: Monday, April 11, 2011
> 5:29 PM To: Shridhar, Vasant Cc: speex-dev at xiph.org Subject: Re:
> [Speex-dev] lpcSize
> On 11-04-11 11:05 AM, Shridhar, Vasant wrote:
>> I would like to make lpcSize a multiple of 4. In the current
>> library for narrow band mode lpcSize is currently set to 10. I
>> would like to increase this 12 for optimization reasons. Is it a
>> simple matter of just changing lpcSize in the structures in mode.c
>> or are there other implications to doing this?
> Nothing major except you'd need to rewrite the LSP quantizer,
> retrain half the codebooks, change the bit-allocation and break
> compatibility with the format.
> Cheers,
> Jean-Marc

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