h264: move q0 scan tables into context

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>

diff --git a/libavcodec/h264.c b/libavcodec/h264.c
index 85787f40d15dd1145c4323981d18d29ac85db64e..7ebe3521b08870da112bc8809379218d040dbc44 100644 (file)
--- a/libavcodec/h264.c
+++ b/libavcodec/h264.c
@@ -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 ));
     }
 }
 

diff --git a/libavcodec/h264.h b/libavcodec/h264.h
index 0e11e304ee5e63c5906ebb838ffd2440d1a9a843..a27f82f4949725f927b7cd1ffa9b209839473a15 100644 (file)
--- a/libavcodec/h264.h
+++ b/libavcodec/h264.h
@@ -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;
 

diff --git a/libavcodec/h264data.h b/libavcodec/h264data.h
index b665bca8c55cb1ee2e63d2cb0d17c83161587fb3..f3fc7f942523afac599c77e8a32c7dd9b53bf76d 100644 (file)
--- a/libavcodec/h264data.h
+++ b/libavcodec/h264data.h
@@ -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 {