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h264: move q0 scan tables into context

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This fixes out of global array reads.
The alternative solutions of checking the index or modifying the VLC tables
to prevent the index going outside are each about 1-2 cpu cyclces slower
per coded 4x4 block.
The alternative of padding the global tables directly is more ugly and
moving them to the context should benefit cache locality.

Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
This commit is contained in:
Michael Niedermayer 2012-05-31 20:19:56 +02:00
parent 18b46a494e
commit b7d1488393
3 changed files with 18 additions and 23 deletions
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24
libavcodec/h264.c
View File

@ -2719,19 +2719,19 @@ static void init_scan_tables(H264Context *h)
#undef T
}
if (h->sps.transform_bypass) { // FIXME same ugly
h->zigzag_scan_q0 = zigzag_scan;
h->zigzag_scan8x8_q0 = ff_zigzag_direct;
h->zigzag_scan8x8_cavlc_q0 = zigzag_scan8x8_cavlc;
h->field_scan_q0 = field_scan;
h->field_scan8x8_q0 = field_scan8x8;
h->field_scan8x8_cavlc_q0 = field_scan8x8_cavlc;
memcpy(h->zigzag_scan_q0 , zigzag_scan , sizeof(h->zigzag_scan_q0 ));
memcpy(h->zigzag_scan8x8_q0 , ff_zigzag_direct , sizeof(h->zigzag_scan8x8_q0 ));
memcpy(h->zigzag_scan8x8_cavlc_q0 , zigzag_scan8x8_cavlc , sizeof(h->zigzag_scan8x8_cavlc_q0));
memcpy(h->field_scan_q0 , field_scan , sizeof(h->field_scan_q0 ));
memcpy(h->field_scan8x8_q0 , field_scan8x8 , sizeof(h->field_scan8x8_q0 ));
memcpy(h->field_scan8x8_cavlc_q0 , field_scan8x8_cavlc , sizeof(h->field_scan8x8_cavlc_q0 ));
} else {
h->zigzag_scan_q0 = h->zigzag_scan;
h->zigzag_scan8x8_q0 = h->zigzag_scan8x8;
h->zigzag_scan8x8_cavlc_q0 = h->zigzag_scan8x8_cavlc;
h->field_scan_q0 = h->field_scan;
h->field_scan8x8_q0 = h->field_scan8x8;
h->field_scan8x8_cavlc_q0 = h->field_scan8x8_cavlc;
memcpy(h->zigzag_scan_q0 , h->zigzag_scan , sizeof(h->zigzag_scan_q0 ));
memcpy(h->zigzag_scan8x8_q0 , h->zigzag_scan8x8 , sizeof(h->zigzag_scan8x8_q0 ));
memcpy(h->zigzag_scan8x8_cavlc_q0 , h->zigzag_scan8x8_cavlc , sizeof(h->zigzag_scan8x8_cavlc_q0));
memcpy(h->field_scan_q0 , h->field_scan , sizeof(h->field_scan_q0 ));
memcpy(h->field_scan8x8_q0 , h->field_scan8x8 , sizeof(h->field_scan8x8_q0 ));
memcpy(h->field_scan8x8_cavlc_q0 , h->field_scan8x8_cavlc , sizeof(h->field_scan8x8_cavlc_q0 ));
}
}

12
libavcodec/h264.h
View File

@ -421,12 +421,12 @@ typedef struct H264Context {
uint8_t field_scan[16];
uint8_t field_scan8x8[64];
uint8_t field_scan8x8_cavlc[64];
const uint8_t *zigzag_scan_q0;
const uint8_t *zigzag_scan8x8_q0;
const uint8_t *zigzag_scan8x8_cavlc_q0;
const uint8_t *field_scan_q0;
const uint8_t *field_scan8x8_q0;
const uint8_t *field_scan8x8_cavlc_q0;
uint8_t zigzag_scan_q0[16];
uint8_t zigzag_scan8x8_q0[64];
uint8_t zigzag_scan8x8_cavlc_q0[64];
uint8_t field_scan_q0[16];
uint8_t field_scan8x8_q0[64];
uint8_t field_scan8x8_cavlc_q0[64];
int x264_build;

5
libavcodec/h264data.h
View File

@ -57,7 +57,6 @@ static const uint8_t zigzag_scan[16+1] = {
1 + 1 * 4, 2 + 0 * 4, 3 + 0 * 4, 2 + 1 * 4,
1 + 2 * 4, 0 + 3 * 4, 1 + 3 * 4, 2 + 2 * 4,
3 + 1 * 4, 3 + 2 * 4, 2 + 3 * 4, 3 + 3 * 4,
0,
};
static const uint8_t field_scan[16+1] = {
@ -65,7 +64,6 @@ static const uint8_t field_scan[16+1] = {
0 + 3 * 4, 1 + 1 * 4, 1 + 2 * 4, 1 + 3 * 4,
2 + 0 * 4, 2 + 1 * 4, 2 + 2 * 4, 2 + 3 * 4,
3 + 0 * 4, 3 + 1 * 4, 3 + 2 * 4, 3 + 3 * 4,
0,
};
static const uint8_t luma_dc_zigzag_scan[16] = {
@ -112,7 +110,6 @@ static const uint8_t zigzag_scan8x8_cavlc[64+1] = {
1 + 4 * 8, 2 + 4 * 8, 6 + 0 * 8, 4 + 3 * 8,
0 + 7 * 8, 4 + 4 * 8, 7 + 2 * 8, 3 + 6 * 8,
5 + 5 * 8, 6 + 5 * 8, 6 + 6 * 8, 7 + 7 * 8,
0,
};
static const uint8_t field_scan8x8[64+1] = {
@ -132,7 +129,6 @@ static const uint8_t field_scan8x8[64+1] = {
7 + 0 * 8, 7 + 1 * 8, 6 + 4 * 8, 6 + 5 * 8,
6 + 6 * 8, 6 + 7 * 8, 7 + 2 * 8, 7 + 3 * 8,
7 + 4 * 8, 7 + 5 * 8, 7 + 6 * 8, 7 + 7 * 8,
0,
};
static const uint8_t field_scan8x8_cavlc[64+1] = {
@ -152,7 +148,6 @@ static const uint8_t field_scan8x8_cavlc[64+1] = {
1 + 7 * 8, 3 + 2 * 8, 2 + 7 * 8, 4 + 2 * 8,
3 + 7 * 8, 5 + 2 * 8, 4 + 7 * 8, 5 + 4 * 8,
6 + 3 * 8, 6 + 5 * 8, 7 + 3 * 8, 7 + 7 * 8,
0,
};
typedef struct IMbInfo {