dnxhd: interleave AC levels and flags

This allows more efficient access to the array as the level and flags
are contiguous. Around 4% faster coefficient decoding.
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>

libavcodec/dnxhddata.h

@@ -46,8 +46,7 @@ typedef struct CIDEntry {
     const uint8_t *luma_weight, *chroma_weight;
     const uint8_t *dc_codes, *dc_bits;
     const uint16_t *ac_codes;
-    const uint8_t *ac_bits, *ac_level;
-    const uint8_t *ac_flags;
+    const uint8_t *ac_bits, *ac_info;
     const uint16_t *run_codes;
     const uint8_t *run_bits, *run;
     int bit_rates[5]; ///< Helper to choose variants, rounded to nearest 5Mb/s

libavcodec/dnxhddec.c

@@ -327,8 +327,7 @@ static av_always_inline int dnxhd_decode_dct_block(const DNXHDContext *ctx,
     int level, component, sign;
     const int *scale;
     const uint8_t *weight_matrix;
-    const uint8_t *ac_level = ctx->cid_table->ac_level;
-    const uint8_t *ac_flags = ctx->cid_table->ac_flags;
+    const uint8_t *ac_info = ctx->cid_table->ac_info;
     int16_t *block = row->blocks[n];
     const int eob_index     = ctx->cid_table->eob_index;
     int ret = 0;
@@ -375,8 +374,8 @@ static av_always_inline int dnxhd_decode_dct_block(const DNXHDContext *ctx,
             DNXHD_VLC_BITS, 2);
 
     while (index1 != eob_index) {
-        level = ac_level[index1];
-        flags = ac_flags[index1];
+        level = ac_info[2*index1+0];
+        flags = ac_info[2*index1+1];
 
         sign = SHOW_SBITS(bs, &row->gb, 1);
         SKIP_BITS(bs, &row->gb, 1);

libavcodec/dnxhdenc.c

@@ -163,9 +163,9 @@ static av_cold int dnxhd_init_vlc(DNXHDEncContext *ctx)
                 alevel -= offset << 6;
             }
             for (j = 0; j < 257; j++) {
-                if (ctx->cid_table->ac_level[j] >> 1 == alevel &&
-                    (!offset || (ctx->cid_table->ac_flags[j] & 1) && offset) &&
-                    (!run    || (ctx->cid_table->ac_flags[j] & 2) && run)) {
+                if (ctx->cid_table->ac_info[2*j+0] >> 1 == alevel &&
+                    (!offset || (ctx->cid_table->ac_info[2*j+1] & 1) && offset) &&
+                    (!run    || (ctx->cid_table->ac_info[2*j+1] & 2) && run)) {
                     av_assert1(!ctx->vlc_codes[index]);
                     if (alevel) {
                         ctx->vlc_codes[index] =