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Clone decode_cabac_residual() for DC residuals, to get rid of a bunch of branches in the main loop. 

Originally committed as revision 14050 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Alexander Strange 2008-07-02 22:08:12 +00:00
parent 2e254bc583
commit 9588ec340c
1 changed files with 44 additions and 15 deletions
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59
libavcodec/h264.c
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@ -5337,24 +5337,28 @@ static int decode_cabac_mb_mvd( H264Context *h, int list, int n, int l ) {
return get_cabac_bypass_sign( &h->cabac, -mvd );
}
static inline int get_cabac_cbf_ctx( H264Context *h, int cat, int idx ) {
static av_always_inline int get_cabac_cbf_ctx( H264Context *h, int cat, int idx, int is_dc ) {
int nza, nzb;
int ctx = 0;
if( is_dc ) {
if( cat == 0 ) {
nza = h->left_cbp&0x100;
nzb = h-> top_cbp&0x100;
} else if( cat == 1 || cat == 2 ) {
nza = h->non_zero_count_cache[scan8[idx] - 1];
nzb = h->non_zero_count_cache[scan8[idx] - 8];
} else if( cat == 3 ) {
} else {
nza = (h->left_cbp>>(6+idx))&0x01;
nzb = (h-> top_cbp>>(6+idx))&0x01;
}
} else {
if( cat == 1 || cat == 2 ) {
nza = h->non_zero_count_cache[scan8[idx] - 1];
nzb = h->non_zero_count_cache[scan8[idx] - 8];
} else {
assert(cat == 4);
nza = h->non_zero_count_cache[scan8[16+idx] - 1];
nzb = h->non_zero_count_cache[scan8[16+idx] - 8];
}
}
if( nza > 0 )
ctx++;
@ -5372,7 +5376,7 @@ DECLARE_ASM_CONST(1, uint8_t, last_coeff_flag_offset_8x8[63]) = {
5, 5, 5, 5, 6, 6, 6, 6, 7, 7, 7, 7, 8, 8, 8
};
static void decode_cabac_residual( H264Context *h, DCTELEM *block, int cat, int n, const uint8_t *scantable, const uint32_t *qmul, int max_coeff) {
static av_always_inline void decode_cabac_residual_internal( H264Context *h, DCTELEM *block, int cat, int n, const uint8_t *scantable, const uint32_t *qmul, int max_coeff, int is_dc ) {
static const int significant_coeff_flag_offset[2][6] = {
{ 105+0, 105+15, 105+29, 105+44, 105+47, 402 },
{ 277+0, 277+15, 277+29, 277+44, 277+47, 436 }
@ -5440,12 +5444,15 @@ static void decode_cabac_residual( H264Context *h, DCTELEM *block, int cat, int
*/
/* read coded block flag */
if( cat != 5 ) {
if( get_cabac( CC, &h->cabac_state[85 + get_cabac_cbf_ctx( h, cat, n ) ] ) == 0 ) {
if( is_dc || cat != 5 ) {
if( get_cabac( CC, &h->cabac_state[85 + get_cabac_cbf_ctx( h, cat, n, is_dc ) ] ) == 0 ) {
if( !is_dc ) {
if( cat == 1 || cat == 2 )
h->non_zero_count_cache[scan8[n]] = 0;
else if( cat == 4 )
else
h->non_zero_count_cache[scan8[16+n]] = 0;
}
#ifdef CABAC_ON_STACK
h->cabac.range = cc.range ;
h->cabac.low = cc.low ;
@ -5462,7 +5469,7 @@ static void decode_cabac_residual( H264Context *h, DCTELEM *block, int cat, int
abs_level_m1_ctx_base = h->cabac_state
+ coeff_abs_level_m1_offset[cat];
if( cat == 5 ) {
if( !is_dc && cat == 5 ) {
#define DECODE_SIGNIFICANCE( coefs, sig_off, last_off ) \
for(last= 0; last < coefs; last++) { \
uint8_t *sig_ctx = significant_coeff_ctx_base + sig_off; \
@ -5491,18 +5498,21 @@ static void decode_cabac_residual( H264Context *h, DCTELEM *block, int cat, int
}
assert(coeff_count > 0);
if( is_dc ) {
if( cat == 0 )
h->cbp_table[h->mb_xy] |= 0x100;
else if( cat == 1 || cat == 2 )
h->non_zero_count_cache[scan8[n]] = coeff_count;
else if( cat == 3 )
else
h->cbp_table[h->mb_xy] |= 0x40 << n;
} else {
if( cat == 1 || cat == 2 )
h->non_zero_count_cache[scan8[n]] = coeff_count;
else if( cat == 4 )
h->non_zero_count_cache[scan8[16+n]] = coeff_count;
else {
assert( cat == 5 );
fill_rectangle(&h->non_zero_count_cache[scan8[n]], 2, 2, 8, coeff_count, 1);
}
}
for( coeff_count--; coeff_count >= 0; coeff_count-- ) {
uint8_t *ctx = coeff_abs_level1_ctx[node_ctx] + abs_level_m1_ctx_base;
@ -5511,7 +5521,7 @@ static void decode_cabac_residual( H264Context *h, DCTELEM *block, int cat, int
if( get_cabac( CC, ctx ) == 0 ) {
node_ctx = coeff_abs_level_transition[0][node_ctx];
if( !qmul ) {
if( is_dc ) {
block[j] = get_cabac_bypass_sign( CC, -1);
}else{
block[j] = (get_cabac_bypass_sign( CC, -qmul[j]) + 32) >> 6;
@ -5538,7 +5548,7 @@ static void decode_cabac_residual( H264Context *h, DCTELEM *block, int cat, int
coeff_abs+= 14;
}
if( !qmul ) {
if( is_dc ) {
if( get_cabac_bypass( CC ) ) block[j] = -coeff_abs;
else block[j] = coeff_abs;
}else{
@ -5555,6 +5565,25 @@ static void decode_cabac_residual( H264Context *h, DCTELEM *block, int cat, int
}
#ifndef CONFIG_SMALL
static void decode_cabac_residual_dc( H264Context *h, DCTELEM *block, int cat, int n, const uint8_t *scantable, const uint32_t *qmul, int max_coeff ) {
decode_cabac_residual_internal(h, block, cat, n, scantable, qmul, max_coeff, 1);
}
static void decode_cabac_residual_nondc( H264Context *h, DCTELEM *block, int cat, int n, const uint8_t *scantable, const uint32_t *qmul, int max_coeff ) {
decode_cabac_residual_internal(h, block, cat, n, scantable, qmul, max_coeff, 0);
}
#endif
static void decode_cabac_residual( H264Context *h, DCTELEM *block, int cat, int n, const uint8_t *scantable, const uint32_t *qmul, int max_coeff ) {
#ifdef CONFIG_SMALL
decode_cabac_residual_internal(h, block, cat, n, scantable, qmul, max_coeff, cat == 0 || cat == 3);
#else
if( cat == 0 || cat == 3 ) decode_cabac_residual_dc(h, block, cat, n, scantable, qmul, max_coeff);
else decode_cabac_residual_nondc(h, block, cat, n, scantable, qmul, max_coeff);
#endif
}
static inline void compute_mb_neighbors(H264Context *h)
{
MpegEncContext * const s = &h->s;