[FFmpeg-devel] [PATCH] dsp optimized float 2 int conversion for wma decoder

Michael Niedermayer michaelni
Tue Sep 4 00:49:39 CEST 2007


Hi

On Mon, Sep 03, 2007 at 11:05:00PM +0200, Benjamin Larsson wrote:
> Old code:
> 
> 3067536 dezicycles in float to int16, 127 runs, 1 skips
> 3086121 dezicycles in float to int16, 254 runs, 2 skips
> 3062931 dezicycles in float to int16, 509 runs, 3 skips
> 3022620 dezicycles in float to int16, 1019 runs, 5 skips
> 2997724 dezicycles in float to int16, 2041 runs, 7 skips
> 
> 
> 
> New code:
> 2651584 dezicycles in simd to int16, 127 runs, 1 skips
> 2668336 dezicycles in simd to int16, 254 runs, 2 skips
> 2672938 dezicycles in simd to int16, 509 runs, 3 skips
> 2677962 dezicycles in simd to int16, 1020 runs, 4 skips
> 2672280 dezicycles in simd to int16, 2041 runs, 7 skips
> 
> 
> Benchmarked from wma_decode_frame start to end.
> 
> Didn't test/benchmark in float mode, will do that if patch is ok.

[...]
> @@ -713,8 +722,9 @@
>  static int wma_decode_frame(WMACodecContext *s, int16_t *samples)
>  {
>      int ret, i, n, ch, incr;
> -    int16_t *ptr;
>      float *iptr;
> +    float tmp[2*s->frame_len];

doesnt this need to be aligned?

and patch ok except that if the output is (nearly) the same

[...]
-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Dictatorship naturally arises out of democracy, and the most aggravated
form of tyranny and slavery out of the most extreme liberty. -- Plato
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