exp2 suffices here. Some trivial (~ 4x) speedup is done in addition here by
reusing results.
This is bit-identical to the old values.
Signed-off-by: Ganesh Ajjanagadde <gajjanaga...@gmail.com>
---
libavcodec/nellymoserenc.c | 11 +++++++++--
1 file changed, 9 insertions(+), 2 deletions(-)
diff --git a/libavcodec/nellymoserenc.c b/libavcodec/nellymoserenc.c
index d998dba..e6023e3 100644
--- a/libavcodec/nellymoserenc.c
+++ b/libavcodec/nellymoserenc.c
@@ -179,8 +179,15 @@ static av_cold int encode_init(AVCodecContext *avctx)
/* Generate overlap window */
ff_init_ff_sine_windows(7);
- for (i = 0; i < POW_TABLE_SIZE; i++)
- pow_table[i] = pow(2, -i / 2048.0 - 3.0 + POW_TABLE_OFFSET);
+ pow_table[0] = 1;
+ pow_table[1024] = M_SQRT1_2;
+ for (i = 1; i < 513; i++) {
+ double tmp = exp2(-i / 2048.0);
+ pow_table[i] = tmp;
+ pow_table[1024-i] = M_SQRT1_2 / tmp;
+ pow_table[1024+i] = tmp * M_SQRT1_2;
+ pow_table[2048-i] = 0.5 / tmp;
+ }
if (s->avctx->trellis) {
s->opt = av_malloc(NELLY_BANDS * OPT_SIZE * sizeof(float ));
--
2.6.3
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