[FFmpeg-devel] [PATCH] SIMD-optimized exponent_min() for ac3enc
Sat Jan 15 04:21:20 CET 2011
This patch adds optimized versions of the exponent_min() function in
ac3enc.c. Exponent encoding has already had some speed-ups earlier
today (benchmarks below) and this will give another 55% speed-up.
Much thanks to Ronald B. for helping me improve PMINUB_MMX.
Benchmarks for exponent_min():
Note: The inner loop runs 1 to 5 times depending on the exponent
strategy in each block, so I modified the AC3 encoder to always use the
same strategy during the benchmarks so the result wouldn't be
content-dependent. All the speeds are slightly faster with the normal
exponent strategy decision.
Benchmarks for encode_exponents() on Athlon64:
r26358: 130051 (exponent_min() is 30%)
patched (sse2): 58905 (exponent_min() is 5%)
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