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Flip (by making buf[i] -> buf[size-i-1]) two buffers: {sp,gain}_block. This 

needs duplicating a few loops, but now the code is clearer.

Originally committed as revision 14634 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Vitor Sessak 2008-08-06 02:44:59 +00:00
parent 00a3431cbb
commit e3751aa6ec
1 changed files with 18 additions and 21 deletions
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39
libavcodec/ra288.c
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@ -70,15 +70,20 @@ static void decode(RA288Context *ractx, float gain, int cb_coef)
int i, j;
double sumsum;
float sum, buffer[5];
float *block = ractx->sp_block + 36; // Current block
memmove(ractx->sp_block + 5, ractx->sp_block, 36*sizeof(*ractx->sp_block));
memmove(ractx->sp_block, ractx->sp_block + 5, 36*sizeof(*ractx->sp_block));
for (i=4; i >= 0; i--)
ractx->sp_block[i] = -scalar_product_float(ractx->sp_block + i + 1,
ractx->sp_lpc, 36);
for (i=0; i < 5; i++) {
block[i] = 0.;
for (j=0; j < 36; j++)
block[i] -= block[i-1-j]*ractx->sp_lpc[j];
}
/* block 46 of G.728 spec */
sum = 32. - scalar_product_float(ractx->gain_lpc, ractx->gain_block, 10);
sum = 32.;
for (i=0; i < 10; i++)
sum -= ractx->gain_block[9-i] * ractx->gain_lpc[i];
/* block 47 of G.728 spec */
sum = av_clipf(sum, 0, 60);
@ -94,10 +99,10 @@ static void decode(RA288Context *ractx, float gain, int cb_coef)
sum = FFMAX(sum, 1);
/* shift and store */
memmove(ractx->gain_block, ractx->gain_block - 1,
10 * sizeof(*ractx->gain_block));
memmove(ractx->gain_block, ractx->gain_block + 1,
9 * sizeof(*ractx->gain_block));
*ractx->gain_block = 10 * log10(sum) - 32;
ractx->gain_block[9] = 10 * log10(sum) - 32;
for (i=1; i < 5; i++)
for (j=i-1; j >= 0; j--)
@ -105,8 +110,7 @@ static void decode(RA288Context *ractx, float gain, int cb_coef)
/* output */
for (i=0; i < 5; i++)
ractx->sp_block[4-i] =
av_clipf(ractx->sp_block[4-i] + buffer[i], -4095, 4095);
block[i] = av_clipf(block[i] + buffer[i], -4095, 4095);
}
/**
@ -157,11 +161,6 @@ static void convolve(float *tgt, const float *src, int len, int n)
/**
* Hybrid window filtering. See blocks 36 and 49 of the G.728 specification.
*
* @note This function is slightly different from that described in the spec.
* It expects in[0] to be the newest sample and in[n-1] to be the oldest
* one stored. The spec has in the more ordinary way (in[0] the oldest
* and in[n-1] the newest).
*
* @param order the order of the filter
* @param n the length of the input
* @param non_rec the number of non-recursive samples
@ -184,9 +183,7 @@ static void do_hybrid_window(int order, int n, int non_rec, const float *in,
/* update history */
memmove(hist, hist + n, (order + non_rec)*sizeof(*hist));
for (i=0; i < n; i++)
hist[order + non_rec + i] = in[n-i-1];
memcpy (hist + order + non_rec, in, n * sizeof(*hist));
colmult(work, window, hist, order + n + non_rec);
@ -210,13 +207,13 @@ static void backward_filter(RA288Context *ractx)
float temp1[37]; // RTMP in the spec
float temp2[11]; // GPTPMP in the spec
do_hybrid_window(36, 40, 35, ractx->sp_block, temp1, ractx->sp_hist,
do_hybrid_window(36, 40, 35, ractx->sp_block+1, temp1, ractx->sp_hist,
ractx->sp_rec, syn_window);
if (!eval_lpc_coeffs(temp1, ractx->sp_lpc, 36))
colmult(ractx->sp_lpc, ractx->sp_lpc, syn_bw_tab, 36);
do_hybrid_window(10, 8, 20, ractx->gain_block, temp2, ractx->gain_hist,
do_hybrid_window(10, 8, 20, ractx->gain_block+2, temp2, ractx->gain_hist,
ractx->gain_rec, gain_window);
if (!eval_lpc_coeffs(temp2, ractx->gain_lpc, 10))
@ -248,7 +245,7 @@ static int ra288_decode_frame(AVCodecContext * avctx, void *data,
decode(ractx, gain, cb_coef);
for (j=0; j < 5; j++)
*(out++) = 8 * ractx->sp_block[4 - j];
*(out++) = 8 * ractx->sp_block[36 + j];
if ((i & 7) == 3)
backward_filter(ractx);