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adpcm: use sign_extend()

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This avoids warnings from the overflow checker and simplifies the code.

Signed-off-by: Mans Rullgard <mans@mansr.com>
This commit is contained in:
Mans Rullgard 2011-10-24 00:08:23 +01:00
parent d99fe3a478
commit c8477df019
1 changed files with 15 additions and 15 deletions
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30
libavcodec/adpcm.c
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@ -824,13 +824,13 @@ static int adpcm_decode_frame(AVCodecContext *avctx,
coeff2r = ea_adpcm_table[(*src & 0x0F) + 4];
src++;
shift_left = (*src >> 4 ) + 8;
shift_right = (*src & 0x0F) + 8;
shift_left = 20 - (*src >> 4);
shift_right = 20 - (*src & 0x0F);
src++;
for (count2 = 0; count2 < 28; count2++) {
next_left_sample = (int32_t)((*src & 0xF0) << 24) >> shift_left;
next_right_sample = (int32_t)((*src & 0x0F) << 28) >> shift_right;
next_left_sample = sign_extend(*src >> 4, 4) << shift_left;
next_right_sample = sign_extend(*src, 4) << shift_right;
src++;
next_left_sample = (next_left_sample +
@ -861,13 +861,13 @@ static int adpcm_decode_frame(AVCodecContext *avctx,
for(channel = 0; channel < avctx->channels; channel++) {
for (i=0; i<2; i++)
coeff[channel][i] = ea_adpcm_table[(*src >> 4) + 4*i];
shift[channel] = (*src & 0x0F) + 8;
shift[channel] = 20 - (*src & 0x0F);
src++;
}
for (count1 = 0; count1 < nb_samples / 2; count1++) {
for(i = 4; i >= 0; i-=4) { /* Pairwise samples LL RR (st) or LL LL (mono) */
for(channel = 0; channel < avctx->channels; channel++) {
int32_t sample = (int32_t)(((*(src+channel) >> i) & 0x0F) << 0x1C) >> shift[channel];
int32_t sample = sign_extend(src[channel] >> i, 4) << shift[channel];
sample = (sample +
c->status[channel].sample1 * coeff[channel][0] +
c->status[channel].sample2 * coeff[channel][1] + 0x80) >> 8;
@ -932,14 +932,14 @@ static int adpcm_decode_frame(AVCodecContext *avctx,
} else {
coeff1 = ea_adpcm_table[ *srcC>>4 ];
coeff2 = ea_adpcm_table[(*srcC>>4) + 4];
shift = (*srcC++ & 0x0F) + 8;
shift = 20 - (*srcC++ & 0x0F);
if (srcC > src_end - 14) break;
for (count2=0; count2<28; count2++) {
if (count2 & 1)
next_sample = (int32_t)((*srcC++ & 0x0F) << 28) >> shift;
next_sample = sign_extend(*srcC++, 4) << shift;
else
next_sample = (int32_t)((*srcC & 0xF0) << 24) >> shift;
next_sample = sign_extend(*srcC >> 4, 4) << shift;
next_sample += (current_sample * coeff1) +
(previous_sample * coeff2);
@ -976,7 +976,7 @@ static int adpcm_decode_frame(AVCodecContext *avctx,
for (n=0; n<4; n++, s+=32*avctx->channels) {
for (i=0; i<2; i++)
coeff[i][n] = ea_adpcm_table[(src[0]&0x0F)+4*i];
shift[n] = (src[2]&0x0F) + 8;
shift[n] = 20 - (src[2] & 0x0F);
for (s2=s, i=0; i<2; i++, src+=2, s2+=avctx->channels)
s2[0] = (src[0]&0xF0) + (src[1]<<8);
}
@ -985,7 +985,7 @@ static int adpcm_decode_frame(AVCodecContext *avctx,
s = &samples[m*avctx->channels + channel];
for (n=0; n<4; n++, src++, s+=32*avctx->channels) {
for (s2=s, i=0; i<8; i+=4, s2+=avctx->channels) {
int level = (int32_t)((*src & (0xF0>>i)) << (24+i)) >> shift[n];
int level = sign_extend(*src >> (4 - i), 4) << shift[n];
int pred = s2[-1*avctx->channels] * coeff[0][n]
+ s2[-2*avctx->channels] * coeff[1][n];
s2[0] = av_clip_int16((level + pred + 0x80) >> 8);
@ -1149,18 +1149,18 @@ static int adpcm_decode_frame(AVCodecContext *avctx,
/* Read in every sample for this channel. */
for (i = 0; i < nb_samples / 14; i++) {
int index = (*src >> 4) & 7;
unsigned int exp = 28 - (*src++ & 15);
unsigned int exp = *src++ & 15;
int factor1 = table[ch][index * 2];
int factor2 = table[ch][index * 2 + 1];
/* Decode 14 samples. */
for (n = 0; n < 14; n++) {
int32_t sampledat;
if(n&1) sampledat= *src++ <<28;
else sampledat= (*src&0xF0)<<24;
if(n&1) sampledat = sign_extend(*src++, 4);
else sampledat = sign_extend(*src >> 4, 4);
sampledat = ((prev[ch][0]*factor1
+ prev[ch][1]*factor2) >> 11) + (sampledat>>exp);
+ prev[ch][1]*factor2) >> 11) + (sampledat << exp);
*samples = av_clip_int16(sampledat);
prev[ch][1] = prev[ch][0];
prev[ch][0] = *samples++;