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aacdec: separate out scalefactor dequantization from decoding

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Allows to template away dequantization.
This commit is contained in:
Lynne 2024-03-13 07:11:22 +01:00
parent ed009bfd3d
commit 60b60dd635
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GPG Key ID: A2FEA5F03F034464
2 changed files with 65 additions and 19 deletions
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1
libavcodec/aacdec.h
View File

@ -147,6 +147,7 @@ typedef struct SingleChannelElement {
TemporalNoiseShaping tns;
enum BandType band_type[128]; ///< band types
int band_type_run_end[120]; ///< band type run end points
int sfo[120]; ///< scalefactor offsets
INTFLOAT_UNION(sf, [120]); ///< scalefactors
INTFLOAT_ALIGNED_UNION(32, coeffs, 1024); ///< coefficients for IMDCT, maybe processed
INTFLOAT_ALIGNED_UNION(32, saved, 1536); ///< overlap

83
libavcodec/aacdec_template.c
View File

@ -1446,7 +1446,8 @@ static int decode_band_types(AACDecContext *ac, enum BandType band_type[120],
*
* @return Returns error status. 0 - OK, !0 - error
*/
static int decode_scalefactors(AACDecContext *ac, INTFLOAT sf[120], GetBitContext *gb,
static int decode_scalefactors(AACDecContext *ac, int sfo[120],
GetBitContext *gb,
unsigned int global_gain,
IndividualChannelStream *ics,
enum BandType band_type[120],
@ -1461,7 +1462,7 @@ static int decode_scalefactors(AACDecContext *ac, INTFLOAT sf[120], GetBitContex
int run_end = band_type_run_end[idx];
if (band_type[idx] == ZERO_BT) {
for (; i < run_end; i++, idx++)
sf[idx] = FIXR(0.);
sfo[idx] = 0;
} else if ((band_type[idx] == INTENSITY_BT) ||
(band_type[idx] == INTENSITY_BT2)) {
for (; i < run_end; i++, idx++) {
@ -1473,11 +1474,7 @@ static int decode_scalefactors(AACDecContext *ac, INTFLOAT sf[120], GetBitContex
"Clipped intensity stereo position (%d -> %d)",
offset[2], clipped_offset);
}
#if USE_FIXED
sf[idx] = 100 - clipped_offset;
#else
sf[idx] = ff_aac_pow2sf_tab[-clipped_offset + POW_SF2_ZERO];
#endif /* USE_FIXED */
sfo[idx] = clipped_offset;
}
} else if (band_type[idx] == NOISE_BT) {
for (; i < run_end; i++, idx++) {
@ -1492,11 +1489,7 @@ static int decode_scalefactors(AACDecContext *ac, INTFLOAT sf[120], GetBitContex
"Clipped noise gain (%d -> %d)",
offset[1], clipped_offset);
}
#if USE_FIXED
sf[idx] = -(100 + clipped_offset);
#else
sf[idx] = -ff_aac_pow2sf_tab[clipped_offset + POW_SF2_ZERO];
#endif /* USE_FIXED */
sfo[idx] = clipped_offset;
}
} else {
for (; i < run_end; i++, idx++) {
@ -1506,11 +1499,7 @@ static int decode_scalefactors(AACDecContext *ac, INTFLOAT sf[120], GetBitContex
"Scalefactor (%d) out of range.\n", offset[0]);
return AVERROR_INVALIDDATA;
}
#if USE_FIXED
sf[idx] = -offset[0];
#else
sf[idx] = -ff_aac_pow2sf_tab[offset[0] - 100 + POW_SF2_ZERO];
#endif /* USE_FIXED */
sfo[idx] = offset[0];
}
}
}
@ -1518,6 +1507,60 @@ static int decode_scalefactors(AACDecContext *ac, INTFLOAT sf[120], GetBitContex
return 0;
}
/**
* Convert integer scalefactors to the decoder's native expected
* scalefactor values.
*/
static void dequant_scalefactors(SingleChannelElement *sce)
{
IndividualChannelStream *ics = &sce->ics;
const enum BandType *band_type = sce->band_type;
const int *band_type_run_end = sce->band_type_run_end;
const int *sfo = sce->sfo;
INTFLOAT *sf = sce->AAC_RENAME(sf);
int g, i, idx = 0;
for (g = 0; g < ics->num_window_groups; g++) {
for (i = 0; i < ics->max_sfb;) {
int run_end = band_type_run_end[idx];
switch (band_type[idx]) {
case ZERO_BT:
for (; i < run_end; i++, idx++)
sf[idx] = FIXR(0.);
break;
case INTENSITY_BT: /* fallthrough */
case INTENSITY_BT2:
for (; i < run_end; i++, idx++) {
#if USE_FIXED
sf[idx] = 100 - sfo[idx];
#else
sf[idx] = ff_aac_pow2sf_tab[-sfo[idx] + POW_SF2_ZERO];
#endif /* USE_FIXED */
}
break;
case NOISE_BT:
for (; i < run_end; i++, idx++) {
#if USE_FIXED
sf[idx] = -(100 + sfo[idx]);
#else
sf[idx] = -ff_aac_pow2sf_tab[sfo[idx] + POW_SF2_ZERO];
#endif /* USE_FIXED */
}
break;
default:
for (; i < run_end; i++, idx++) {
#if USE_FIXED
sf[idx] = -sfo[idx];
#else
sf[idx] = -ff_aac_pow2sf_tab[sfo[idx] - 100 + POW_SF2_ZERO];
#endif /* USE_FIXED */
}
break;
}
}
}
}
/**
* Decode pulse data; reference: table 4.7.
*/
@ -2007,10 +2050,12 @@ static int decode_ics(AACDecContext *ac, SingleChannelElement *sce,
if ((ret = decode_band_types(ac, sce->band_type,
sce->band_type_run_end, gb, ics)) < 0)
goto fail;
if ((ret = decode_scalefactors(ac, sce->AAC_RENAME(sf), gb, global_gain, ics,
sce->band_type, sce->band_type_run_end)) < 0)
if ((ret = decode_scalefactors(ac, sce->sfo, gb, global_gain, ics,
sce->band_type, sce->band_type_run_end)) < 0)
goto fail;
dequant_scalefactors(sce);
pulse_present = 0;
if (!scale_flag) {
if (!eld_syntax && (pulse_present = get_bits1(gb))) {