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Partially fix CDLMS prediction

This commit is contained in:
Mashiat Sarker Shakkhar 2011-12-08 03:57:21 +06:00
parent 460bec6800
commit c5cd231151
1 changed files with 58 additions and 60 deletions
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118
libavcodec/wmalosslessdec.c
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@ -776,11 +776,12 @@ static void reset_codec(WmallDecodeCtx *s)
s->mclms_recent = s->mclms_order * s->num_channels;
for (ich = 0; ich < s->num_channels; ich++) {
for (ilms = 0; ilms < s->cdlms_ttl[ich]; ilms++)
s->cdlms[ich][ilms].recent = s->cdlms[ich][ilms].order - 1;
s->cdlms[ich][ilms].recent = s->cdlms[ich][ilms].order;
/* first sample of a seekable subframe is considered as the starting of
a transient area which is samples_per_frame samples long */
s->channel[ich].transient_counter = s->samples_per_frame;
s->transient[ich] = 1;
s->transient_pos[ich] = 0;
}
}
@ -875,7 +876,7 @@ static void revert_mclms(WmallDecodeCtx *s, int tile_size)
static int lms_predict(WmallDecodeCtx *s, int ich, int ilms)
{
int16_t pred = 0;
int pred = 0;
int icoef;
int recent = s->cdlms[ich][ilms].recent;
@ -883,39 +884,53 @@ static int lms_predict(WmallDecodeCtx *s, int ich, int ilms)
pred += s->cdlms[ich][ilms].coefs[icoef] *
s->cdlms[ich][ilms].lms_prevvalues[icoef + recent];
pred += (1 << (s->cdlms[ich][ilms].scaling - 1));
//pred += (1 << (s->cdlms[ich][ilms].scaling - 1));
/* XXX: Table 29 has:
iPred >= cdlms[iCh][ilms].scaling;
seems to me like a missing > */
pred >>= s->cdlms[ich][ilms].scaling;
//pred >>= s->cdlms[ich][ilms].scaling;
return pred;
}
static void lms_update(WmallDecodeCtx *s, int ich, int ilms, int16_t residue, int16_t pred)
static void lms_update(WmallDecodeCtx *s, int ich, int ilms, int input, int residue)
{
int16_t icoef;
int icoef;
int recent = s->cdlms[ich][ilms].recent;
int16_t range = (1 << s->bits_per_sample - 1) - 1;
int range = 1 << s->bits_per_sample - 1;
int bps = s->bits_per_sample > 16 ? 4 : 2; // bytes per sample
int16_t input = residue + pred;
if (residue > 0) {
for (icoef = 0; icoef < s->cdlms[ich][ilms].order; icoef++)
s->cdlms[ich][ilms].coefs[icoef] +=
s->cdlms[ich][ilms].lms_updates[icoef + recent];
} else {
if (residue < 0) {
for (icoef = 0; icoef < s->cdlms[ich][ilms].order; icoef++)
s->cdlms[ich][ilms].coefs[icoef] -=
s->cdlms[ich][ilms].lms_updates[icoef + recent];
} else if (residue > 0) {
for (icoef = 0; icoef < s->cdlms[ich][ilms].order; icoef++)
s->cdlms[ich][ilms].coefs[icoef] +=
s->cdlms[ich][ilms].lms_updates[icoef + recent]; /* spec mistakenly
dropped the recent */
}
s->cdlms[ich][ilms].recent--;
s->cdlms[ich][ilms].lms_prevvalues[recent] = av_clip(input, -range, range - 1);
if (input > pred)
s->cdlms[ich][ilms].lms_updates[recent] = s->update_speed[ich];
else if (input < pred)
if (recent)
recent--;
else {
/* XXX: This memcpy()s will probably fail if a fixed 32-bit buffer is used.
follow kshishkov's suggestion of using a union. */
memcpy(&s->cdlms[ich][ilms].lms_prevvalues[s->cdlms[ich][ilms].order],
s->cdlms[ich][ilms].lms_prevvalues,
bps * s->cdlms[ich][ilms].order);
memcpy(&s->cdlms[ich][ilms].lms_updates[s->cdlms[ich][ilms].order],
s->cdlms[ich][ilms].lms_updates,
bps * s->cdlms[ich][ilms].order);
recent = s->cdlms[ich][ilms].order - 1;
}
s->cdlms[ich][ilms].lms_prevvalues[recent] = av_clip(input, -range, range - 1);
if (!input)
s->cdlms[ich][ilms].lms_updates[recent] = 0;
else if (input < 0)
s->cdlms[ich][ilms].lms_updates[recent] = -s->update_speed[ich];
else
s->cdlms[ich][ilms].lms_updates[recent] = s->update_speed[ich];
/* XXX: spec says:
cdlms[iCh][ilms].updates[iRecent + cdlms[iCh][ilms].order >> 4] >>= 2;
@ -925,21 +940,9 @@ static void lms_update(WmallDecodeCtx *s, int ich, int ilms, int16_t residue, in
seperate buffers? Here I've assumed that the two are same which makes
more sense to me.
*/
s->cdlms[ich][ilms].lms_updates[recent + s->cdlms[ich][ilms].order >> 4] >>= 2;
s->cdlms[ich][ilms].lms_updates[recent + s->cdlms[ich][ilms].order >> 3] >>= 1;
/* XXX: recent + (s->cdlms[ich][ilms].order >> 4) ? */
if (s->cdlms[ich][ilms].recent == 0) {
/* XXX: This memcpy()s will probably fail if a fixed 32-bit buffer is used.
follow kshishkov's suggestion of using a union. */
memcpy(s->cdlms[ich][ilms].lms_prevvalues + s->cdlms[ich][ilms].order,
s->cdlms[ich][ilms].lms_prevvalues,
bps * s->cdlms[ich][ilms].order);
memcpy(s->cdlms[ich][ilms].lms_updates + s->cdlms[ich][ilms].order,
s->cdlms[ich][ilms].lms_updates,
bps * s->cdlms[ich][ilms].order);
s->cdlms[ich][ilms].recent = s->cdlms[ich][ilms].order;
}
s->cdlms[ich][ilms].lms_updates[recent + (s->cdlms[ich][ilms].order >> 4)] >>= 2;
s->cdlms[ich][ilms].lms_updates[recent + (s->cdlms[ich][ilms].order >> 3)] >>= 1;
s->cdlms[ich][ilms].recent = recent;
}
static void use_high_update_speed(WmallDecodeCtx *s, int ich)
@ -974,33 +977,23 @@ static void use_normal_update_speed(WmallDecodeCtx *s, int ich)
}
}
static void revert_cdlms(WmallDecodeCtx *s, int tile_size)
static void revert_cdlms(WmallDecodeCtx *s, int ch, int coef_begin, int coef_end)
{
int icoef, ich;
int16_t pred, channel_coeff;
int icoef;
int pred;
int ilms, num_lms;
int residue, input;
for (ich = 0; ich < s->num_channels; ich++) {
if (!s->is_channel_coded[ich])
continue;
num_lms = s->cdlms_ttl[ich];
for (icoef = 0; icoef < tile_size; icoef++) {
channel_coeff = s->channel_residues[ich][icoef];
if (icoef == s->transient_pos[ich]) {
s->transient[ich] = 1;
use_high_update_speed(s, ich);
}
for (ilms = num_lms - 1; ilms >= 0; ilms--) {
pred = lms_predict(s, ich, ilms);
lms_update(s, ich, ilms, channel_coeff, pred);
channel_coeff += pred;
}
if (s->transient[ich]) {
--s->channel[ich].transient_counter;
if(!s->channel[ich].transient_counter)
use_normal_update_speed(s, ich);
}
s->channel_coeffs[ich][icoef] = channel_coeff;
num_lms = s->cdlms_ttl[ch];
for (ilms = num_lms - 1; ilms >= 0; ilms--) {
//s->cdlms[ch][ilms].recent = s->cdlms[ch][ilms].order;
for (icoef = coef_begin; icoef < coef_end; icoef++) {
pred = 1 << (s->cdlms[ch][ilms].scaling - 1);
residue = s->channel_residues[ch][icoef];
pred += lms_predict(s, ch, ilms);
input = residue + (pred >> s->cdlms[ch][ilms].scaling);
lms_update(s, ch, ilms, input, residue);
s->channel_residues[ch][icoef] = input;
}
}
}
@ -1130,10 +1123,15 @@ static int decode_subframe(WmallDecodeCtx *s)
}
} else {
for(i = 0; i < s->num_channels; i++)
if(s->is_channel_coded[i])
decode_channel_residues(s, i, subframe_len);
if(s->is_channel_coded[i]) {
decode_channel_residues(s, i, subframe_len);
if (s->seekable_tile)
use_high_update_speed(s, i);
else
use_normal_update_speed(s, i);
revert_cdlms(s, i, 0, subframe_len);
}
}
revert_cdlms(s, subframe_len);
/** handled one subframe */