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alacenc: fix extra bits extraction 

The raw coded bits are extracted prior to decorrelation, as is correctly
performed by the decoder, and not after.

Fixes ticket #2768.

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
This commit is contained in:
Christophe Gisquet 2014-08-17 18:56:45 +02:00 committed by Michael Niedermayer
parent c0d18cc085
commit 96d2178325
1 changed files with 14 additions and 2 deletions
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16
libavcodec/alacenc.c
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@ -394,6 +394,19 @@ static void write_element(AlacEncodeContext *s,
init_sample_buffers(s, channels, samples);
write_element_header(s, element, instance);
// extract extra bits if needed
if (s->extra_bits) {
uint32_t mask = (1 << s->extra_bits) - 1;
for (j = 0; j < channels; j++) {
int32_t *extra = s->predictor_buf[j];
int32_t *smp = s->sample_buf[j];
for (i = 0; i < s->frame_size; i++) {
extra[i] = smp[i] & mask;
smp[i] >>= s->extra_bits;
}
}
}
if (channels == 2)
alac_stereo_decorrelation(s);
else
@ -419,8 +432,7 @@ static void write_element(AlacEncodeContext *s,
uint32_t mask = (1 << s->extra_bits) - 1;
for (i = 0; i < s->frame_size; i++) {
for (j = 0; j < channels; j++) {
put_bits(pb, s->extra_bits, s->sample_buf[j][i] & mask);
s->sample_buf[j][i] >>= s->extra_bits;
put_bits(pb, s->extra_bits, s->predictor_buf[j][i] & mask);
}
}
}