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Change the way the input is passed to do_hybrid_filter(). Before, in[0] was

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the oldest input sample passed and in[n-1] was the latest. Now it is the
contrary. This allows making backward_filter() somewhat simpler.

Originally committed as revision 14447 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Vitor Sessak 2008-07-28 02:55:47 +00:00
parent aed39f6c02
commit 2b356efec2
1 changed files with 10 additions and 12 deletions
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22
libavcodec/ra288.c
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@ -153,6 +153,11 @@ static void prodsum(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
@ -175,7 +180,9 @@ 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));
memcpy (hist + order + non_rec, in , n *sizeof(*hist));
for (x=0; x < n; x++)
hist[order + non_rec + x] = in[n-x-1];
colmult(work, window, hist, order + n + non_rec);
@ -198,23 +205,14 @@ static void backward_filter(RA288Context *ractx)
{
float temp1[37]; // RTMP in the spec
float temp2[11]; // GPTPMP in the spec
float history[8];
float speech[40];
int i;
for (i=0 ; i < 8; i++)
history[i] = ractx->lhist[7-i];
for (i=0; i < 40; i++)
speech[i] = ractx->sb[39-i];
do_hybrid_window(36, 40, 35, speech, temp1, ractx->sp_hist,
do_hybrid_window(36, 40, 35, ractx->sb, 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, history, temp2, ractx->gain_hist,
do_hybrid_window(10, 8, 20, ractx->lhist, temp2, ractx->gain_hist,
ractx->gain_rec, gain_window);
if (!eval_lpc_coeffs(temp2, ractx->gain_lpc, 10))