From 8d359bbabee104a2c79e54d76e5f086bb5d49b1f Mon Sep 17 00:00:00 2001
From: Michael Niedermayer <michaelni@gmx.at>
Date: Thu, 2 Mar 2006 13:55:49 +0000
Subject: [PATCH] cleanup IMA-ADPCM WAV decoder
Originally committed as revision 5095 to svn://svn.ffmpeg.org/ffmpeg/trunk
---
libavcodec/adpcm.c | 43 +++++++++++++++++++++----------------------
1 file changed, 21 insertions(+), 22 deletions(-)
diff --git a/libavcodec/adpcm.c b/libavcodec/adpcm.c
index de66daf7dbe..86abbf799f9 100644
--- a/libavcodec/adpcm.c
+++ b/libavcodec/adpcm.c
@@ -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];
@@ -721,35 +723,32 @@ 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++;
+ src += 4*st;
}
break;
case CODEC_ID_ADPCM_4XM:
--
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