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adpcmenc: fix QT IMA ADPCM encoder 

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
This commit is contained in:
Baptiste Coudurier 2011-09-07 22:27:03 -04:00 committed by Justin Ruggles
parent bf334535b4
commit b304244b54
2 changed files with 38 additions and 7 deletions
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39
libavcodec/adpcmenc.c
View File

@ -164,6 +164,39 @@ static inline unsigned char adpcm_ima_compress_sample(ADPCMChannelStatus *c, sho
return nibble;
}
static inline unsigned char adpcm_ima_qt_compress_sample(ADPCMChannelStatus *c, short sample)
{
int delta = sample - c->prev_sample;
int mask, step = ff_adpcm_step_table[c->step_index];
int diff = step >> 3;
int nibble = 0;
if (delta < 0) {
nibble = 8;
delta = -delta;
}
for (mask = 4; mask;) {
if (delta >= step) {
nibble |= mask;
delta -= step;
diff += step;
}
step >>= 1;
mask >>= 1;
}
if (nibble & 8)
c->prev_sample -= diff;
else
c->prev_sample += diff;
c->prev_sample = av_clip_int16(c->prev_sample);
c->step_index = av_clip(c->step_index + ff_adpcm_index_table[nibble], 0, 88);
return nibble;
}
static inline unsigned char adpcm_ms_compress_sample(ADPCMChannelStatus *c, short sample)
{
int predictor, nibble, bias;
@ -497,16 +530,14 @@ static int adpcm_encode_frame(AVCodecContext *avctx,
adpcm_compress_trellis(avctx, samples+ch, buf, &c->status[ch], 64);
for(i=0; i<64; i++)
put_bits(&pb, 4, buf[i^1]);
c->status[ch].prev_sample = c->status[ch].predictor & ~0x7F;
} else {
for (i=0; i<64; i+=2){
int t1, t2;
t1 = adpcm_ima_compress_sample(&c->status[ch], samples[avctx->channels*(i+0)+ch]);
t2 = adpcm_ima_compress_sample(&c->status[ch], samples[avctx->channels*(i+1)+ch]);
t1 = adpcm_ima_qt_compress_sample(&c->status[ch], samples[avctx->channels*(i+0)+ch]);
t2 = adpcm_ima_qt_compress_sample(&c->status[ch], samples[avctx->channels*(i+1)+ch]);
put_bits(&pb, 4, t2);
put_bits(&pb, 4, t1);
}
c->status[ch].prev_sample &= ~0x7F;
}
}

6
tests/ref/acodec/adpcm_ima_qt
View File

@ -1,4 +1,4 @@
019564da45949d0b5278bd75ee9a4ac2 *./tests/data/acodec/adpcm_qt.aiff
057d27978b35888776512e4e9669a63b *./tests/data/acodec/adpcm_qt.aiff
281252 ./tests/data/acodec/adpcm_qt.aiff
a7fb054f7bd82270c8fd476eb9f5677c *./tests/data/adpcm_ima_qt.acodec.out.wav
stddev: 920.19 PSNR: 37.05 MAXDIFF:34029 bytes: 1058560/ 1058400
3890343c0c20934e014d7ac93f5d65bd *./tests/data/adpcm_ima_qt.acodec.out.wav
stddev: 918.61 PSNR: 37.07 MAXDIFF:34029 bytes: 1058560/ 1058400