[FFmpeg-devel] [PATCH] Port AAC decoder to use ff_imdct_half and vector_fmul_window

Robert Swain robert.swain
Fri Aug 22 16:03:44 CEST 2008


Attached are:
0001-Separate-IMDCT-and-windowing-into-imdct-windowing-a.patch
I thought the current layout of the code was quite difficult to look
at as it mixes imdct, windowing and buffer updates. I decided
separating them into clearer sections made the code more easy to
understand and think about.

0002-Whitespace-cosmetics.patch
This cleans up alignment and such after 0001.

0003-Use-imdct_half-and-fmul_window.-Reduce-buffer-sizes.patch
Does exactly what it says on the tin. :) I observe an ~10% performance
improvement after these patches.

Comments welcome as always. Benchmarks are below for this file.

Regards,
Rob


Benchmarks on a Core Duo 1.83GHz on a 320kbps FAAC encoded South Park episode.

before:
real	0m8.001s
user	0m7.222s
sys	0m0.479s

real	0m7.922s
user	0m7.372s
sys	0m0.481s

real	0m7.555s
user	0m7.055s
sys	0m0.459s

real	0m7.707s
user	0m7.129s
sys	0m0.470s

real	0m7.371s
user	0m6.816s
sys	0m0.452s


after:
real	0m7.534s
user	0m6.843s
sys	0m0.486s

real	0m7.421s
user	0m6.763s
sys	0m0.464s

real	0m7.590s
user	0m7.074s
sys	0m0.465s

real	0m6.609s
user	0m6.173s
sys	0m0.405s

real	0m7.745s
user	0m7.157s
sys	0m0.483s
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