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Code Issues Releases Activity

avcodec/h264_cavlc: Avoid indirection for coefficient table VLCs

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Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
This commit is contained in:
Andreas Rheinhardt 2023-09-20 18:30:13 +02:00
parent fe748ddf62
commit bd4c778e19
1 changed files with 12 additions and 5 deletions
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17
libavcodec/h264_cavlc.c
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@ -246,7 +246,8 @@ static int8_t cavlc_level_tab[7][1<<LEVEL_TAB_BITS][2];
#define RUN_VLC_BITS 3
#define RUN7_VLC_BITS 6
static const VLCElem *coeff_token_vlc[4];
/// 17 pointers to only four different VLCs
static const VLCElem *coeff_token_vlc[17];
static VLCElem chroma_dc_coeff_token_vlc_table[256];
@ -313,6 +314,7 @@ static av_cold void init_cavlc_level_tab(void){
av_cold void ff_h264_decode_init_vlc(void)
{
const VLCElem *coeff_token_vlc_original[4];
VLCInitState state = VLC_INIT_STATE(run7_vlc_table);
VLC_INIT_STATIC_TABLE(chroma_dc_coeff_token_vlc_table,
@ -336,11 +338,17 @@ av_cold void ff_h264_decode_init_vlc(void)
}
for (int i = 0; i < 4; i++) {
coeff_token_vlc[i] =
coeff_token_vlc_original[i] =
ff_vlc_init_tables(&state, COEFF_TOKEN_VLC_BITS, 4*17,
&coeff_token_len [i][0], 1, 1,
&coeff_token_bits[i][0], 1, 1, 0);
}
for (int i = 0; i < FF_ARRAY_ELEMS(coeff_token_vlc); i++) {
static const uint8_t coeff_token_table_index[17] = {
0, 0, 1, 1, 2, 2, 2, 2, 3, 3, 3, 3, 3, 3, 3, 3, 3
};
coeff_token_vlc[i] = coeff_token_vlc_original[coeff_token_table_index[i]];
}
for (int i = 0; i < 3; i++) {
chroma_dc_total_zeros_vlc[i + 1] =
@ -399,7 +407,6 @@ static int decode_residual(const H264Context *h, H264SliceContext *sl,
const uint8_t *scantable, const uint32_t *qmul,
int max_coeff)
{
static const int coeff_token_table_index[17]= {0, 0, 1, 1, 2, 2, 2, 2, 3, 3, 3, 3, 3, 3, 3, 3, 3};
int level[16];
int zeros_left, coeff_token, total_coeff, i, trailing_ones, run_before;
@ -416,12 +423,12 @@ static int decode_residual(const H264Context *h, H264SliceContext *sl,
}else{
if(n >= LUMA_DC_BLOCK_INDEX){
total_coeff= pred_non_zero_count(h, sl, (n - LUMA_DC_BLOCK_INDEX)*16);
coeff_token = get_vlc2(gb, coeff_token_vlc[coeff_token_table_index[total_coeff]],
coeff_token = get_vlc2(gb, coeff_token_vlc[total_coeff],
COEFF_TOKEN_VLC_BITS, 2);
total_coeff= coeff_token>>2;
}else{
total_coeff= pred_non_zero_count(h, sl, n);
coeff_token = get_vlc2(gb, coeff_token_vlc[coeff_token_table_index[total_coeff]],
coeff_token = get_vlc2(gb, coeff_token_vlc[total_coeff],
COEFF_TOKEN_VLC_BITS, 2);
total_coeff= coeff_token>>2;
}