[FFmpeg-devel] [PATCH] Implement AAC Long Term Prediction (LTP) decoding module

Rob robert.swain
Thu Feb 10 10:05:51 CET 2011

On 10 February 2011 09:46, Rob <robert.swain at gmail.com> wrote:
> On 10 February 2011 06:23, Alex Converse <alex.converse at gmail.com> wrote:
>> This version looks good.
>> Does anyone else have comments?
> I'll have a look over it shortly.

My only concerns are that the expansion/addition of data arrays is
significant. There's a 1024 element float array, a 3072 element
int16_t array and an additional 1024 elements in another float array.
I'm not saying that this needs to block merging, but if there is a way
to improve it, perhaps we can add some comments as to how.

Is the int16_t array really needed? We output float anyway don't we so
perhaps there is a way to translate the method to use float all the
way through. I seem to remember when I switched to using imdct_half
and vector_fmul I was able to reduce the array sizes somewhat. Is
there any possibility of this for this ltp code? Things like that.

Generally, the code looks very neat and gets the OK from me as long as
it has been tested with relevant clips and works. :) Good job!


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