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avcodec/aacdec_common: Avoid superfluous VLC structures

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For all VLCs here, the number of bits of the VLC is
write-only, because it is hardcoded at the call site.
Therefore one can replace these VLC structures with
the only thing that is actually used: The pointer
to the VLCElem table. And in some cases one can even
avoid this.

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
This commit is contained in:
Andreas Rheinhardt 2023-09-24 23:04:11 +02:00
parent 0e8abf2698
commit 4d6042e9d7
3 changed files with 28 additions and 31 deletions
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43
libavcodec/aacdec_common.c
View File

@ -123,36 +123,33 @@ const AVChannelLayout ff_aac_ch_layout[] = {
{ 0 },
};
VLC ff_vlc_scalefactors;
VLC ff_vlc_spectral[11];
VLCElem ff_vlc_scalefactors[352];
const VLCElem *ff_vlc_spectral[11];
static av_cold void aacdec_common_init(void)
{
static VLCElem vlc_buf[304 + 270 + 550 + 300 + 328 +
294 + 306 + 268 + 510 + 366 + 462];
for (unsigned i = 0, offset = 0; i < 11; i++) {
ff_vlc_spectral[i].table = &vlc_buf[offset];
ff_vlc_spectral[i].table_allocated = FF_ARRAY_ELEMS(vlc_buf) - offset;
ff_vlc_init_sparse(&ff_vlc_spectral[i], 8, ff_aac_spectral_sizes[i],
ff_aac_spectral_bits[i], sizeof(ff_aac_spectral_bits[i][0]),
sizeof(ff_aac_spectral_bits[i][0]),
ff_aac_spectral_codes[i], sizeof(ff_aac_spectral_codes[i][0]),
sizeof(ff_aac_spectral_codes[i][0]),
ff_aac_codebook_vector_idx[i], sizeof(ff_aac_codebook_vector_idx[i][0]),
sizeof(ff_aac_codebook_vector_idx[i][0]),
VLC_INIT_STATIC_OVERLONG);
offset += ff_vlc_spectral[i].table_size;
VLCInitState state = VLC_INIT_STATE(vlc_buf);
for (unsigned i = 0; i < 11; i++) {
#define TAB_WRAP_SIZE(name) name[i], sizeof(name[i][0]), sizeof(name[i][0])
ff_vlc_spectral[i] =
ff_vlc_init_tables_sparse(&state, 8, ff_aac_spectral_sizes[i],
TAB_WRAP_SIZE(ff_aac_spectral_bits),
TAB_WRAP_SIZE(ff_aac_spectral_codes),
TAB_WRAP_SIZE(ff_aac_codebook_vector_idx),
0);
}
VLC_INIT_STATIC(&ff_vlc_scalefactors, 7,
FF_ARRAY_ELEMS(ff_aac_scalefactor_code),
ff_aac_scalefactor_bits,
sizeof(ff_aac_scalefactor_bits[0]),
sizeof(ff_aac_scalefactor_bits[0]),
ff_aac_scalefactor_code,
sizeof(ff_aac_scalefactor_code[0]),
sizeof(ff_aac_scalefactor_code[0]),
352);
VLC_INIT_STATIC_TABLE(ff_vlc_scalefactors, 7,
FF_ARRAY_ELEMS(ff_aac_scalefactor_code),
ff_aac_scalefactor_bits,
sizeof(ff_aac_scalefactor_bits[0]),
sizeof(ff_aac_scalefactor_bits[0]),
ff_aac_scalefactor_code,
sizeof(ff_aac_scalefactor_code[0]),
sizeof(ff_aac_scalefactor_code[0]), 0);
}
av_cold void ff_aacdec_common_init_once(void)

12
libavcodec/aacdec_template.c
View File

@ -1497,7 +1497,7 @@ static int decode_scalefactors(AACContext *ac, INTFLOAT sf[120], GetBitContext *
} else if ((band_type[idx] == INTENSITY_BT) ||
(band_type[idx] == INTENSITY_BT2)) {
for (; i < run_end; i++, idx++) {
offset[2] += get_vlc2(gb, ff_vlc_scalefactors.table, 7, 3) - SCALE_DIFF_ZERO;
offset[2] += get_vlc2(gb, ff_vlc_scalefactors, 7, 3) - SCALE_DIFF_ZERO;
clipped_offset = av_clip(offset[2], -155, 100);
if (offset[2] != clipped_offset) {
avpriv_request_sample(ac->avctx,
@ -1516,7 +1516,7 @@ static int decode_scalefactors(AACContext *ac, INTFLOAT sf[120], GetBitContext *
if (noise_flag-- > 0)
offset[1] += get_bits(gb, NOISE_PRE_BITS) - NOISE_PRE;
else
offset[1] += get_vlc2(gb, ff_vlc_scalefactors.table, 7, 3) - SCALE_DIFF_ZERO;
offset[1] += get_vlc2(gb, ff_vlc_scalefactors, 7, 3) - SCALE_DIFF_ZERO;
clipped_offset = av_clip(offset[1], -100, 155);
if (offset[1] != clipped_offset) {
avpriv_request_sample(ac->avctx,
@ -1532,7 +1532,7 @@ static int decode_scalefactors(AACContext *ac, INTFLOAT sf[120], GetBitContext *
}
} else {
for (; i < run_end; i++, idx++) {
offset[0] += get_vlc2(gb, ff_vlc_scalefactors.table, 7, 3) - SCALE_DIFF_ZERO;
offset[0] += get_vlc2(gb, ff_vlc_scalefactors, 7, 3) - SCALE_DIFF_ZERO;
if (offset[0] > 255U) {
av_log(ac->avctx, AV_LOG_ERROR,
"Scalefactor (%d) out of range.\n", offset[0]);
@ -1705,7 +1705,7 @@ static int decode_spectrum_and_dequant(AACContext *ac, INTFLOAT coef[1024],
#if !USE_FIXED
const float *vq = ff_aac_codebook_vector_vals[cbt_m1];
#endif /* !USE_FIXED */
const VLCElem *vlc_tab = ff_vlc_spectral[cbt_m1].table;
const VLCElem *vlc_tab = ff_vlc_spectral[cbt_m1];
OPEN_READER(re, gb);
switch (cbt_m1 >> 1) {
@ -2279,7 +2279,7 @@ static int decode_cce(AACContext *ac, GetBitContext *gb, ChannelElement *che)
INTFLOAT gain_cache = FIXR10(1.);
if (c) {
cge = coup->coupling_point == AFTER_IMDCT ? 1 : get_bits1(gb);
gain = cge ? get_vlc2(gb, ff_vlc_scalefactors.table, 7, 3) - 60: 0;
gain = cge ? get_vlc2(gb, ff_vlc_scalefactors, 7, 3) - 60: 0;
gain_cache = GET_GAIN(scale, gain);
#if USE_FIXED
if ((abs(gain_cache)-1024) >> 3 > 30)
@ -2293,7 +2293,7 @@ static int decode_cce(AACContext *ac, GetBitContext *gb, ChannelElement *che)
for (sfb = 0; sfb < sce->ics.max_sfb; sfb++, idx++) {
if (sce->band_type[idx] != ZERO_BT) {
if (!cge) {
int t = get_vlc2(gb, ff_vlc_scalefactors.table, 7, 3) - 60;
int t = get_vlc2(gb, ff_vlc_scalefactors, 7, 3) - 60;
if (t) {
int s = 1;
t = gain += t;

4
libavcodec/aacdectab.h
View File

@ -38,8 +38,8 @@
FF_VISIBILITY_PUSH_HIDDEN
void ff_aacdec_common_init_once(void);
extern VLC ff_vlc_scalefactors;
extern VLC ff_vlc_spectral[11];
extern VLCElem ff_vlc_scalefactors[];
extern const VLCElem *ff_vlc_spectral[11];
extern const int8_t ff_tags_per_config[16];