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cleanup IMA-ADPCM WAV decoder 

Originally committed as revision 5095 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Michael Niedermayer 2006-03-02 13:55:49 +00:00
parent 6a8eb0f45a
commit 8d359bbabe
1 changed files with 21 additions and 22 deletions
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43
libavcodec/adpcm.c
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@ -694,8 +694,10 @@ static int adpcm_decode_frame(AVCodecContext *avctx,
cs->step_index = (*src++) & 0x7F;
if (cs->step_index > 88) av_log(avctx, AV_LOG_ERROR, "ERROR: step_index = %i\n", cs->step_index);
if (cs->step_index > 88) cs->step_index = 88;
if (cs->step_index > 88){
av_log(avctx, AV_LOG_ERROR, "ERROR: step_index = %i\n", cs->step_index);
cs->step_index = 88;
}
cs->step = step_table[cs->step_index];
@ -721,36 +723,33 @@ static int adpcm_decode_frame(AVCodecContext *avctx,
if (avctx->block_align != 0 && buf_size > avctx->block_align)
buf_size = avctx->block_align;
// samples_per_block= (block_align-4*chanels)*8 / (bits_per_sample * chanels) + 1;
for(i=0; i<avctx->channels; i++){
cs = &(c->status[i]);
cs->predictor = *src++;
cs->predictor |= (*src++) << 8;
if(cs->predictor & 0x8000)
cs->predictor -= 0x10000;
CLAMP_TO_SHORT(cs->predictor);
cs->predictor = (int16_t)(src[0] + (src[1]<<8));
src+=2;
// XXX: is this correct ??: *samples++ = cs->predictor;
cs->step_index = *src++;
if (cs->step_index < 0) cs->step_index = 0;
if (cs->step_index > 88) cs->step_index = 88;
if (*src++) av_log(avctx, AV_LOG_ERROR, "unused byte should be null !!\n"); /* unused */
if (cs->step_index > 88){
av_log(avctx, AV_LOG_ERROR, "ERROR: step_index = %i\n", cs->step_index);
cs->step_index = 88;
}
if (*src++) av_log(avctx, AV_LOG_ERROR, "unused byte should be null but is %d!!\n", src[-1]); /* unused */
}
for(m=4; src < (buf + buf_size);) {
*samples++ = adpcm_ima_expand_nibble(&c->status[0], src[0] & 0x0F, 3);
if (st)
*samples++ = adpcm_ima_expand_nibble(&c->status[1], src[4] & 0x0F, 3);
*samples++ = adpcm_ima_expand_nibble(&c->status[0], (src[0] >> 4) & 0x0F, 3);
if (st) {
*samples++ = adpcm_ima_expand_nibble(&c->status[1], (src[4] >> 4) & 0x0F, 3);
if (!--m) {
m=4;
src+=4;
}
}
while(src < buf + buf_size){
for(m=0; m<4; m++){
for(i=0; i<=st; i++)
*samples++ = adpcm_ima_expand_nibble(&c->status[i], src[4*i] & 0x0F, 3);
for(i=0; i<=st; i++)
*samples++ = adpcm_ima_expand_nibble(&c->status[i], src[4*i] >> 4 , 3);
src++;
}
src += 4*st;
}
break;
case CODEC_ID_ADPCM_4XM:
cs = &(c->status[0]);