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Small simplification

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Originally committed as revision 11026 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Benjamin Larsson 2007-11-14 16:33:14 +00:00
parent 97c8b06470
commit 2b992d0e88
1 changed files with 7 additions and 9 deletions
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16
libavcodec/nellymoserdec.c
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@ -123,9 +123,9 @@ static void overlap_and_window(NellyMoserDecodeContext *s, float *state, float *
while (bot < NELLY_BUF_LEN/4) { while (bot < NELLY_BUF_LEN/4) {
s_bot = audio[bot]; s_bot = audio[bot];
s_top = audio[top]; s_top = -audio[top];
audio[bot] = (audio[mid_up]*sine_window[bot]-state[bot ]*sine_window[top])/s->scale_bias + s->add_bias; audio[bot] = (-audio[mid_up]*sine_window[bot]-state[bot ]*sine_window[top])/s->scale_bias + s->add_bias;
audio[top] = (-state[bot ]*sine_window[bot]-audio[mid_up]*sine_window[top])/s->scale_bias + s->add_bias; audio[top] = (-state[bot ]*sine_window[bot]+audio[mid_up]*sine_window[top])/s->scale_bias + s->add_bias;
state[bot] = audio[mid_down]; state[bot] = audio[mid_down];
audio[mid_down] = (s_top *sine_window[mid_down]-state[mid_down]*sine_window[mid_up])/s->scale_bias + s->add_bias; audio[mid_down] = (s_top *sine_window[mid_down]-state[mid_down]*sine_window[mid_up])/s->scale_bias + s->add_bias;
@ -281,7 +281,6 @@ void nelly_decode_block(NellyMoserDecodeContext *s, unsigned char block[NELLY_BL
float *aptr, *bptr, *pptr, val, pval; float *aptr, *bptr, *pptr, val, pval;
int bits[NELLY_BUF_LEN]; int bits[NELLY_BUF_LEN];
unsigned char v; unsigned char v;
float a;
init_get_bits(&s->gb, block, NELLY_BLOCK_LEN * 8); init_get_bits(&s->gb, block, NELLY_BLOCK_LEN * 8);
@ -324,10 +323,9 @@ void nelly_decode_block(NellyMoserDecodeContext *s, unsigned char block[NELLY_BL
aptr, s->imdct_tmp); aptr, s->imdct_tmp);
/* XXX: overlapping and windowing should be part of a more /* XXX: overlapping and windowing should be part of a more
generic imdct function */ generic imdct function */
a = 1.0 / 8.0;
for(j = 0; j < NELLY_BUF_LEN / 2; j++) { for(j = 0; j < NELLY_BUF_LEN / 2; j++) {
aptr[j] = s->imdct_out[j + NELLY_BUF_LEN + NELLY_BUF_LEN / 2] * a; aptr[j] = s->imdct_out[j + NELLY_BUF_LEN + NELLY_BUF_LEN / 2];
aptr[j + NELLY_BUF_LEN / 2] = -s->imdct_out[j] * a; aptr[j + NELLY_BUF_LEN / 2] = s->imdct_out[j];
} }
overlap_and_window(s, s->state, aptr); overlap_and_window(s, s->state, aptr);
} }
@ -345,10 +343,10 @@ static int decode_init(AVCodecContext * avctx) {
if(s->dsp.float_to_int16 == ff_float_to_int16_c) { if(s->dsp.float_to_int16 == ff_float_to_int16_c) {
s->add_bias = 385; s->add_bias = 385;
s->scale_bias = 32768; s->scale_bias = 8*32768;
} else { } else {
s->add_bias = 0; s->add_bias = 0;
s->scale_bias = 1; s->scale_bias = 1*8;
} }
/* Generate overlap window */ /* Generate overlap window */