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avcodec/rv34: Avoid superfluous VLC structures 

For most 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.

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
This commit is contained in:
Andreas Rheinhardt 2023-09-24 15:08:09 +02:00
parent 73fa6d486d
commit 716ddc8c62
2 changed files with 49 additions and 37 deletions
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74
libavcodec/rv34.c
View File

@ -90,8 +90,8 @@ static VLCElem table_data[117592];
* @param insyms symbols for input codes (NULL for default ones)
* @param num VLC table number (for static initialization)
*/
static void rv34_gen_vlc(const uint8_t *bits, int size, VLC *vlc, const uint8_t *syms,
int *offset)
static av_cold void rv34_gen_vlc_ext(const uint8_t *bits, int size, VLC *vlc,
const uint8_t *syms, int *offset)
{
int counts[17] = {0}, codes[17];
uint16_t cw[MAX_VLC_SIZE];
@ -120,6 +120,14 @@ static void rv34_gen_vlc(const uint8_t *bits, int size, VLC *vlc, const uint8_t
*offset += vlc->table_size;
}
static av_cold void rv34_gen_vlc(const uint8_t *bits, int size, const VLCElem **vlcp,
int *offset)
{
VLC vlc = { 0 };
rv34_gen_vlc_ext(bits, size, &vlc, NULL, offset);
*vlcp = vlc.table;
}
/**
* Initialize all tables.
*/
@ -130,41 +138,41 @@ static av_cold void rv34_init_tables(void)
for(i = 0; i < NUM_INTRA_TABLES; i++){
for(j = 0; j < 2; j++){
rv34_gen_vlc(rv34_table_intra_cbppat [i][j], CBPPAT_VLC_SIZE,
&intra_vlcs[i].cbppattern[j], NULL, &offset);
&intra_vlcs[i].cbppattern[j], &offset);
rv34_gen_vlc(rv34_table_intra_secondpat[i][j], OTHERBLK_VLC_SIZE,
&intra_vlcs[i].second_pattern[j], NULL, &offset);
&intra_vlcs[i].second_pattern[j], &offset);
rv34_gen_vlc(rv34_table_intra_thirdpat [i][j], OTHERBLK_VLC_SIZE,
&intra_vlcs[i].third_pattern[j], NULL, &offset);
&intra_vlcs[i].third_pattern[j], &offset);
for(k = 0; k < 4; k++){
rv34_gen_vlc(rv34_table_intra_cbp[i][j+k*2], CBP_VLC_SIZE,
&intra_vlcs[i].cbp[j][k], rv34_cbp_code, &offset);
rv34_gen_vlc_ext(rv34_table_intra_cbp[i][j+k*2], CBP_VLC_SIZE,
&intra_vlcs[i].cbp[j][k], rv34_cbp_code, &offset);
}
}
for(j = 0; j < 4; j++){
rv34_gen_vlc(rv34_table_intra_firstpat[i][j], FIRSTBLK_VLC_SIZE,
&intra_vlcs[i].first_pattern[j], NULL, &offset);
&intra_vlcs[i].first_pattern[j], &offset);
}
rv34_gen_vlc(rv34_intra_coeff[i], COEFF_VLC_SIZE,
&intra_vlcs[i].coefficient, NULL, &offset);
&intra_vlcs[i].coefficient, &offset);
}
for(i = 0; i < NUM_INTER_TABLES; i++){
rv34_gen_vlc(rv34_inter_cbppat[i], CBPPAT_VLC_SIZE,
&inter_vlcs[i].cbppattern[0], NULL, &offset);
&inter_vlcs[i].cbppattern[0], &offset);
for(j = 0; j < 4; j++){
rv34_gen_vlc(rv34_inter_cbp[i][j], CBP_VLC_SIZE,
&inter_vlcs[i].cbp[0][j], rv34_cbp_code, &offset);
rv34_gen_vlc_ext(rv34_inter_cbp[i][j], CBP_VLC_SIZE,
&inter_vlcs[i].cbp[0][j], rv34_cbp_code, &offset);
}
for(j = 0; j < 2; j++){
rv34_gen_vlc(rv34_table_inter_firstpat [i][j], FIRSTBLK_VLC_SIZE,
&inter_vlcs[i].first_pattern[j], NULL, &offset);
&inter_vlcs[i].first_pattern[j], &offset);
rv34_gen_vlc(rv34_table_inter_secondpat[i][j], OTHERBLK_VLC_SIZE,
&inter_vlcs[i].second_pattern[j], NULL, &offset);
&inter_vlcs[i].second_pattern[j], &offset);
rv34_gen_vlc(rv34_table_inter_thirdpat [i][j], OTHERBLK_VLC_SIZE,
&inter_vlcs[i].third_pattern[j], NULL, &offset);
&inter_vlcs[i].third_pattern[j], &offset);
}
rv34_gen_vlc(rv34_inter_coeff[i], COEFF_VLC_SIZE,
&inter_vlcs[i].coefficient, NULL, &offset);
&inter_vlcs[i].coefficient, &offset);
}
}
@ -187,7 +195,7 @@ static int rv34_decode_cbp(GetBitContext *gb, RV34VLC *vlc, int table)
const int *curshift = shifts;
int i, t, mask;
code = get_vlc2(gb, vlc->cbppattern[table].table, 9, 2);
code = get_vlc2(gb, vlc->cbppattern[table], 9, 2);
pattern = code & 0xF;
code >>= 4;
@ -211,11 +219,12 @@ static int rv34_decode_cbp(GetBitContext *gb, RV34VLC *vlc, int table)
/**
* Get one coefficient value from the bitstream and store it.
*/
static inline void decode_coeff(int16_t *dst, int coef, int esc, GetBitContext *gb, VLC* vlc, int q)
static inline void decode_coeff(int16_t *dst, int coef, int esc, GetBitContext *gb,
const VLCElem *vlc, int q)
{
if(coef){
if(coef == esc){
coef = get_vlc2(gb, vlc->table, 9, 2);
coef = get_vlc2(gb, vlc, 9, 2);
if(coef > 23){
coef -= 23;
coef = 22 + ((1 << coef) | get_bits(gb, coef));
@ -231,7 +240,8 @@ static inline void decode_coeff(int16_t *dst, int coef, int esc, GetBitContext *
/**
* Decode 2x2 subblock of coefficients.
*/
static inline void decode_subblock(int16_t *dst, int code, const int is_block2, GetBitContext *gb, VLC *vlc, int q)
static inline void decode_subblock(int16_t *dst, int code, const int is_block2,
GetBitContext *gb, const VLCElem *vlc, int q)
{
int flags = modulo_three_table[code];
@ -249,13 +259,15 @@ static inline void decode_subblock(int16_t *dst, int code, const int is_block2,
/**
* Decode a single coefficient.
*/
static inline void decode_subblock1(int16_t *dst, int code, GetBitContext *gb, VLC *vlc, int q)
static inline void decode_subblock1(int16_t *dst, int code, GetBitContext *gb,
const VLCElem *vlc, int q)
{
int coeff = modulo_three_table[code] >> 6;
decode_coeff(dst, coeff, 3, gb, vlc, q);
}
static inline void decode_subblock3(int16_t *dst, int code, GetBitContext *gb, VLC *vlc,
static inline void decode_subblock3(int16_t *dst, int code, GetBitContext *gb,
const VLCElem *vlc,
int q_dc, int q_ac1, int q_ac2)
{
int flags = modulo_three_table[code];
@ -281,32 +293,32 @@ static int rv34_decode_block(int16_t *dst, GetBitContext *gb, RV34VLC *rvlc, int
{
int code, pattern, has_ac = 1;
code = get_vlc2(gb, rvlc->first_pattern[fc].table, 9, 2);
code = get_vlc2(gb, rvlc->first_pattern[fc], 9, 2);
pattern = code & 0x7;
code >>= 3;
if (modulo_three_table[code] & 0x3F) {
decode_subblock3(dst, code, gb, &rvlc->coefficient, q_dc, q_ac1, q_ac2);
decode_subblock3(dst, code, gb, rvlc->coefficient, q_dc, q_ac1, q_ac2);
} else {
decode_subblock1(dst, code, gb, &rvlc->coefficient, q_dc);
decode_subblock1(dst, code, gb, rvlc->coefficient, q_dc);
if (!pattern)
return 0;
has_ac = 0;
}
if(pattern & 4){
code = get_vlc2(gb, rvlc->second_pattern[sc].table, 9, 2);
decode_subblock(dst + 4*0+2, code, 0, gb, &rvlc->coefficient, q_ac2);
code = get_vlc2(gb, rvlc->second_pattern[sc], 9, 2);
decode_subblock(dst + 4*0+2, code, 0, gb, rvlc->coefficient, q_ac2);
}
if(pattern & 2){ // Looks like coefficients 1 and 2 are swapped for this block
code = get_vlc2(gb, rvlc->second_pattern[sc].table, 9, 2);
decode_subblock(dst + 4*2+0, code, 1, gb, &rvlc->coefficient, q_ac2);
code = get_vlc2(gb, rvlc->second_pattern[sc], 9, 2);
decode_subblock(dst + 4*2+0, code, 1, gb, rvlc->coefficient, q_ac2);
}
if(pattern & 1){
code = get_vlc2(gb, rvlc->third_pattern[sc].table, 9, 2);
decode_subblock(dst + 4*2+2, code, 0, gb, &rvlc->coefficient, q_ac2);
code = get_vlc2(gb, rvlc->third_pattern[sc], 9, 2);
decode_subblock(dst + 4*2+2, code, 0, gb, rvlc->coefficient, q_ac2);
}
return has_ac | pattern;
}

12
libavcodec/rv34.h
View File

@ -63,12 +63,12 @@ enum RV40BlockTypes{
* Intra frame VLC sets do not contain some of those tables.
*/
typedef struct RV34VLC{
VLC cbppattern[2]; ///< VLCs used for pattern of coded block patterns decoding
VLC cbp[2][4]; ///< VLCs used for coded block patterns decoding
VLC first_pattern[4]; ///< VLCs used for decoding coefficients in the first subblock
VLC second_pattern[2]; ///< VLCs used for decoding coefficients in the subblocks 2 and 3
VLC third_pattern[2]; ///< VLCs used for decoding coefficients in the last subblock
VLC coefficient; ///< VLCs used for decoding big coefficients
const VLCElem *cbppattern[2]; ///< VLCs used for pattern of coded block patterns decoding
VLC cbp[2][4]; ///< VLCs used for coded block patterns decoding
const VLCElem *first_pattern[4]; ///< VLCs used for decoding coefficients in the first subblock
const VLCElem *second_pattern[2]; ///< VLCs used for decoding coefficients in the subblocks 2 and 3
const VLCElem *third_pattern[2]; ///< VLCs used for decoding coefficients in the last subblock
const VLCElem *coefficient; ///< VLCs used for decoding big coefficients
}RV34VLC;
/** essential slice information */