return (short)c->predictor;
}
+static inline int adpcm_ima_qt_expand_nibble(ADPCMChannelStatus *c, int nibble, int shift)
+{
+ int step_index;
+ int predictor;
+ int diff, step;
+
+ step = ff_adpcm_step_table[c->step_index];
+ step_index = c->step_index + ff_adpcm_index_table[nibble];
+ step_index = av_clip(step_index, 0, 88);
+
+ diff = step >> 3;
+ if (nibble & 4) diff += step;
+ if (nibble & 2) diff += step >> 1;
+ if (nibble & 1) diff += step >> 2;
+
+ if (nibble & 8)
+ predictor = c->predictor - diff;
+ else
+ predictor = c->predictor + diff;
+
+ c->predictor = av_clip_int16(predictor);
+ c->step_index = step_index;
+
+ return c->predictor;
+}
+
static inline short adpcm_ms_expand_nibble(ADPCMChannelStatus *c, char nibble)
{
int predictor;
case CODEC_ID_ADPCM_IMA_QT:
n = buf_size - 2*avctx->channels;
for (channel = 0; channel < avctx->channels; channel++) {
+ int16_t predictor;
+ int step_index;
cs = &(c->status[channel]);
/* (pppppp) (piiiiiii) */
/* Bits 15-7 are the _top_ 9 bits of the 16-bit initial predictor value */
- cs->predictor = (*src++) << 8;
- cs->predictor |= (*src & 0x80);
- cs->predictor &= 0xFF80;
-
- /* sign extension */
- if(cs->predictor & 0x8000)
- cs->predictor -= 0x10000;
-
- cs->predictor = av_clip_int16(cs->predictor);
-
- cs->step_index = (*src++) & 0x7F;
+ predictor = AV_RB16(src);
+ step_index = predictor & 0x7F;
+ predictor &= 0xFF80;
+
+ src += 2;
+
+ if (cs->step_index == step_index) {
+ int diff = (int)predictor - cs->predictor;
+ if (diff < 0)
+ diff = - diff;
+ if (diff > 0x7f)
+ goto update;
+ } else {
+ update:
+ cs->step_index = step_index;
+ cs->predictor = predictor;
+ }
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 = ff_adpcm_step_table[cs->step_index];
-
samples = (short*)data + channel;
for(m=32; n>0 && m>0; n--, m--) { /* in QuickTime, IMA is encoded by chuncks of 34 bytes (=64 samples) */
- *samples = adpcm_ima_expand_nibble(cs, src[0] & 0x0F, 3);
+ *samples = adpcm_ima_qt_expand_nibble(cs, src[0] & 0x0F, 3);
samples += avctx->channels;
- *samples = adpcm_ima_expand_nibble(cs, src[0] >> 4 , 3);
+ *samples = adpcm_ima_qt_expand_nibble(cs, src[0] >> 4 , 3);
samples += avctx->channels;
src ++;
}