avcodec/ffv1: add a named constant for the quant table size

Sponsored-by: Sovereign Tech Fund
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
(cherry picked from commit 81a360a5ed)
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>

libavcodec/ffv1.h

@@ -44,6 +44,8 @@
 #define CONTEXT_SIZE 32
 
 #define MAX_QUANT_TABLES 8
+#define MAX_QUANT_TABLE_SIZE 256
+#define MAX_QUANT_TABLE_MASK (MAX_QUANT_TABLE_SIZE - 1)
 #define MAX_CONTEXT_INPUTS 5
 
 #define AC_GOLOMB_RICE          0
@@ -123,7 +125,7 @@ typedef struct FFV1Context {
     const AVFrame *cur_enc_frame;
     int plane_count;
     int ac;                              ///< 1=range coder <-> 0=golomb rice
-    int16_t quant_tables[MAX_QUANT_TABLES][MAX_CONTEXT_INPUTS][256];
+    int16_t quant_tables[MAX_QUANT_TABLES][MAX_CONTEXT_INPUTS][MAX_QUANT_TABLE_SIZE];
     int context_count[MAX_QUANT_TABLES];
     uint8_t state_transition[256];
     uint8_t (*initial_states[MAX_QUANT_TABLES])[32];

libavcodec/ffv1_template.c

@@ -29,7 +29,7 @@ static inline int RENAME(predict)(TYPE *src, TYPE *last)
     return mid_pred(L, L + T - LT, T);
 }
 
-static inline int RENAME(get_context)(const int16_t quant_table[MAX_CONTEXT_INPUTS][256],
+static inline int RENAME(get_context)(const int16_t quant_table[MAX_CONTEXT_INPUTS][MAX_QUANT_TABLE_SIZE],
                                       TYPE *src, TYPE *last, TYPE *last2)
 {
     const int LT = last[-1];
@@ -40,14 +40,14 @@ static inline int RENAME(get_context)(const int16_t quant_table[MAX_CONTEXT_INPU
     if (quant_table[3][127] || quant_table[4][127]) {
         const int TT = last2[0];
         const int LL = src[-2];
-        return quant_table[0][(L - LT) & 0xFF] +
-               quant_table[1][(LT - T) & 0xFF] +
-               quant_table[2][(T - RT) & 0xFF] +
-               quant_table[3][(LL - L) & 0xFF] +
-               quant_table[4][(TT - T) & 0xFF];
+        return quant_table[0][(L - LT) & MAX_QUANT_TABLE_MASK] +
+               quant_table[1][(LT - T) & MAX_QUANT_TABLE_MASK] +
+               quant_table[2][(T - RT) & MAX_QUANT_TABLE_MASK] +
+               quant_table[3][(LL - L) & MAX_QUANT_TABLE_MASK] +
+               quant_table[4][(TT - T) & MAX_QUANT_TABLE_MASK];
     } else
-        return quant_table[0][(L - LT) & 0xFF] +
-               quant_table[1][(LT - T) & 0xFF] +
-               quant_table[2][(T - RT) & 0xFF];
+        return quant_table[0][(L - LT) & MAX_QUANT_TABLE_MASK] +
+               quant_table[1][(LT - T) & MAX_QUANT_TABLE_MASK] +
+               quant_table[2][(T - RT) & MAX_QUANT_TABLE_MASK];
 }
 

libavcodec/ffv1enc.c

@@ -317,7 +317,7 @@ static void write_quant_table(RangeCoder *c, int16_t *quant_table)
     uint8_t state[CONTEXT_SIZE];
     memset(state, 128, sizeof(state));
 
-    for (i = 1; i < 128; i++)
+    for (i = 1; i < MAX_QUANT_TABLE_SIZE/2; i++)
         if (quant_table[i] != quant_table[i - 1]) {
             put_symbol(c, state, i - last - 1, 0);
             last = i;
@@ -326,7 +326,7 @@ static void write_quant_table(RangeCoder *c, int16_t *quant_table)
 }
 
 static void write_quant_tables(RangeCoder *c,
-                               int16_t quant_table[MAX_CONTEXT_INPUTS][256])
+                               int16_t quant_table[MAX_CONTEXT_INPUTS][MAX_QUANT_TABLE_SIZE])
 {
     int i;
     for (i = 0; i < 5; i++)
@@ -718,7 +718,7 @@ static av_cold int encode_init(AVCodecContext *avctx)
             s->state_transition[i] = c.one_state[i];
     }
 
-    for (i = 0; i < 256; i++) {
+    for (i = 0; i < MAX_QUANT_TABLE_SIZE; i++) {
         s->quant_table_count = 2;
         if (s->bits_per_raw_sample <= 8) {
             s->quant_tables[0][0][i]=           quant11[i];