[vorbis-dev] Optimizing Vorbis for a DSP

[Graham Mitchell]

> I have recently ported Vorbis to a Texas instruments DSP (TMS320C5510),
> The problem I have is that it is not decoding the audio in real time(
> about 50% of real time). Could any one give me a clue in which area I
> could start to optimize the code.

Well, a few weeks ago Johannes Sandvall posted to the list about "replacing 
the IMDCT with a N/4 FFT", which I seem to recall gave a large speedup; his 
report is here:
        http://www.sandvall.nu/thesis.pdf

And my crufty brain seems to recall that profiling has determined that more 
time is spent in the function "mdct_backward" than any other, but I could be 
way off base.

Others on the list are much more qualified than I am, but sometimes a faster, 
mediocre response is better than a slower, perfect one.  At least that's 
what I'm banking on, anyway.


-- 
Graham Mitchell - computer science teacher, Leander High School
"We draw people to Christ not by loudly discrediting what they believe, by
telling them how wrong they are and how right we are, but by showing them a
light that is so lovely that they want with all their hearts to know the
source of it."
	-- Madeleine L'Engle, "Walking on Water"

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