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Replace big square-root table by a call to ff_sqrt(). Based on a patch

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by Reimar Döffinger.

Originally committed as revision 20281 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Vitor Sessak 2009-10-18 16:29:10 +00:00
parent 8da1d52cc1
commit a0228397af
1 changed files with 4 additions and 17 deletions
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21
libavcodec/roqaudioenc.c
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@ -29,7 +29,6 @@
#define MAX_DPCM (127*127) #define MAX_DPCM (127*127)
static unsigned char dpcmValues[MAX_DPCM];
typedef struct typedef struct
@ -37,18 +36,6 @@ typedef struct
short lastSample[2]; short lastSample[2];
} ROQDPCMContext; } ROQDPCMContext;
static av_cold void roq_dpcm_table_init(void)
{
int i;
/* Create a table of quick DPCM values */
for (i=0; i<MAX_DPCM; i++) {
int s= ff_sqrt(i);
int mid= s*s + s;
dpcmValues[i]= s + (i>mid);
}
}
static av_cold int roq_dpcm_encode_init(AVCodecContext *avctx) static av_cold int roq_dpcm_encode_init(AVCodecContext *avctx)
{ {
ROQDPCMContext *context = avctx->priv_data; ROQDPCMContext *context = avctx->priv_data;
@ -66,8 +53,6 @@ static av_cold int roq_dpcm_encode_init(AVCodecContext *avctx)
return -1; return -1;
} }
roq_dpcm_table_init();
avctx->frame_size = ROQ_FIRST_FRAME_SIZE; avctx->frame_size = ROQ_FIRST_FRAME_SIZE;
context->lastSample[0] = context->lastSample[1] = 0; context->lastSample[0] = context->lastSample[1] = 0;
@ -92,8 +77,10 @@ static unsigned char dpcm_predict(short *previous, short current)
if (diff >= MAX_DPCM) if (diff >= MAX_DPCM)
result = 127; result = 127;
else else {
result = dpcmValues[diff]; result = ff_sqrt(diff);
result += diff > result*result+result;
}
/* See if this overflows */ /* See if this overflows */
retry: retry: