[FFmpeg-cvslog] avcodec/aacdec_common: Avoid superfluous VLC structures
Andreas Rheinhardt
git at videolan.org
Tue Oct 31 23:19:47 EET 2023
ffmpeg | branch: master | Andreas Rheinhardt <andreas.rheinhardt at outlook.com> | Sun Sep 24 23:04:11 2023 +0200| [4d6042e9d7f89c94c434b082685d93e3f96e00ed] | committer: Andreas Rheinhardt
avcodec/aacdec_common: Avoid superfluous VLC structures
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 at outlook.com>
> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=4d6042e9d7f89c94c434b082685d93e3f96e00ed
---
libavcodec/aacdec_common.c | 43 ++++++++++++++++++++-----------------------
libavcodec/aacdec_template.c | 12 ++++++------
libavcodec/aacdectab.h | 4 ++--
3 files changed, 28 insertions(+), 31 deletions(-)
diff --git a/libavcodec/aacdec_common.c b/libavcodec/aacdec_common.c
index 45f1986258..61d81343fe 100644
--- a/libavcodec/aacdec_common.c
+++ b/libavcodec/aacdec_common.c
@@ -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)
diff --git a/libavcodec/aacdec_template.c b/libavcodec/aacdec_template.c
index 65dd8b4bf9..2b3509c85f 100644
--- a/libavcodec/aacdec_template.c
+++ b/libavcodec/aacdec_template.c
@@ -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;
diff --git a/libavcodec/aacdectab.h b/libavcodec/aacdectab.h
index a009e9f46e..d62f170136 100644
--- a/libavcodec/aacdectab.h
+++ b/libavcodec/aacdectab.h
@@ -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];
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