Bug fixes. 32 bit loss should be working now. MacOS may still have a …

…problem.

src/core/coding/ojph_block_common.cpp

@@ -84,18 +84,29 @@ namespace ojph {
      *  + 4 * mel event for initial row of quads when needed                 \n
      *                                                                       \n
      *  Each entry contains, starting from the LSB                           \n
-     *  \li \c total prefix length for quads 0 and 1 (3 bits)                \n
-     *  \li \c total suffix length for quads 0 and 1 (4 bits)                \n
+     *  \li \c total total prefix length for quads 0 and 1 (3 bits)          \n
+     *  \li \c total total suffix length for quads 0 and 1 (4 bits)          \n
      *  \li \c suffix length for quad 0 (3 bits)                             \n
      *  \li \c prefix for quad 0 (3 bits)                                    \n
      *  \li \c prefix for quad 1 (3 bits)                                    \n
+     *                                                                       \n
+     *  Another table is uvlc_bias, which is needed to correctly decode the 
+     *  extension u_ext for initial row of quads. Under certain condition,
+     *  we deduct 1 or 2 from u_q0 and u_q1 before encoding them; so for us 
+     *  to know that decoding u_ext is needed, we recreate the u_q0 and u_q1
+     *  that we actually encoded.                                            \n
+     *  For simplicity, we use the same index as before                      \n
+     *  \li \c u_q0 bias is 2 bits                                           \n
+     *  \li \c u_q1 bias is 2 bits                                           \n
      */
 
     /// @brief uvlc_tbl0 contains decoding information for initial row of quads
     ui16 uvlc_tbl0[256+64] = { 0 };
     /// @brief uvlc_tbl1 contains decoding information for non-initial row of 
     ///        quads
     ui16 uvlc_tbl1[256] = { 0 };
+    /// @brief uvlc_bias contains decoding info. for initial row of quads
+    ui8 uvlc_bias[256+64] = { 0 };
     /// @}
 
     //************************************************************************/
@@ -199,8 +210,10 @@ namespace ojph {
         ui32 mode = i >> 6;
         ui32 vlc = i & 0x3F;
 
-        if (mode == 0)      // both u_off are 0
+        if (mode == 0) {      // both u_off are 0
           uvlc_tbl0[i] = 0;
+          uvlc_bias[i] = 0;
+        }
         else if (mode <= 2) // u_off are either 01 or 10
         {
           ui32 d = dec[vlc & 0x7];   //look at the least significant 3 bits
@@ -232,6 +245,7 @@ namespace ojph {
             total_suffix = u0_suffix_len;
             u0 = d0 >> 5;
             u1 = (vlc & 1) + 1;
+            uvlc_bias[i] = 4; // 0b00 for u0 and 0b01 for u1
           }
           else
           {
@@ -240,6 +254,7 @@ namespace ojph {
             total_suffix = u0_suffix_len + ((d1 >> 2) & 0x7);
             u0 = d0 >> 5;
             u1 = d1 >> 5;
+            uvlc_bias[i] = 0;
           }
 
           uvlc_tbl0[i] = (ui16)(total_prefix | 
@@ -265,6 +280,7 @@ namespace ojph {
                                (u0_suffix_len << 7) |
                                (u0 << 10) |
                                (u1 << 13));
+          uvlc_bias[i] = 10; // 0b10 for u0 and 0b10 for u1
         }
       }
 

src/core/coding/ojph_block_common.h

@@ -44,6 +44,6 @@ namespace ojph{
     extern ui16 vlc_tbl1[1024];
     extern ui16 uvlc_tbl0[256+64];
     extern ui16 uvlc_tbl1[256];
-
+    extern ui8 uvlc_bias[256+64];
   } // !namespace local
 } // !namespace ojph

src/core/coding/ojph_block_decoder.cpp

@@ -2025,7 +2025,9 @@ namespace ojph {
           //  run = mel_get_run(&mel);  // get another run
 
           //decode uvlc_mode to get u for both quads
-          ui32 uvlc_entry = uvlc_tbl0[uvlc_mode + (vlc_val & 0x3F)];
+          ui32 idx = uvlc_mode + (ui32)(vlc_val & 0x3F);
+          ui32 uvlc_entry = uvlc_tbl0[idx];
+          ui16 u_bias = uvlc_bias[idx];          
           //remove total prefix length
           vlc_val = rev_advance64(&vlc, uvlc_entry & 0x7); 
           uvlc_entry >>= 3; 
@@ -2037,21 +2039,21 @@ namespace ojph {
           // quad 0 length
           len = uvlc_entry & 0x7; // quad 0 suffix length
           uvlc_entry >>= 3;
-          ui16 u_q0 = (ui16)(1 + (uvlc_entry&7) + (tmp&~(0xFFU<<len)));//kap. 1
-          ui16 u_q1 = (ui16)(1 + (uvlc_entry >> 3) + (tmp >> len));  //kappa==1
+          ui16 u_q0 = (ui16)((uvlc_entry & 7) + (tmp & ~(0xFFU << len)));
+          ui16 u_q1 = (ui16)((uvlc_entry >> 3) + (tmp >> len));
 
           // decode u_q extensions, which is needed only when u_q > 32
           ui16 u_ext; bool cond0, cond1;
-          cond0 = u_q0 > 32;
-          u_ext = (ui16)(cond0 ? (uvlc_entry & 0xF) : 0);
+          cond0 = u_q0 - (u_bias & 0x3) > 32;
+          u_ext = (ui16)(cond0 ? (vlc_val & 0xF) : 0);
           vlc_val = rev_advance64(&vlc, cond0 ? 4 : 0);
           u_q0 = (ui16)(u_q0 + (u_ext << 2));
-          sp[1] = u_q0;
-          cond1 = u_q1 > 32;
-          u_ext = (ui16)(cond1 ? (uvlc_entry & 0xF) : 0);
+          sp[1] = u_q0 + 1; // kappa = 1
+          cond1 = u_q1 - (u_bias >> 2) > 32;
+          u_ext = (ui16)(cond1 ? (vlc_val & 0xF) : 0);
           vlc_val = rev_advance64(&vlc, cond1 ? 4 : 0);
           u_q1 = (ui16)(u_q1 + (u_ext << 2));
-          sp[3] = u_q1;
+          sp[3] = u_q1 + 1; // kappa = 1
         }
         sp[0] = sp[1] = 0;
 
@@ -2165,12 +2167,12 @@ namespace ojph {
             // decode u_q extensions, which is needed only when u_q > 32
             ui16 u_ext; bool cond0, cond1;
             cond0 = u_q0 > 32;
-            u_ext = (ui16)(cond0 ? (uvlc_entry & 0xF) : 0);
+            u_ext = (ui16)(cond0 ? (vlc_val & 0xF) : 0);
             vlc_val = rev_advance64(&vlc, cond0 ? 4 : 0);
             u_q0 = (ui16)(u_q0 + (u_ext << 2));
             sp[1] = u_q0;
             cond1 = u_q1 > 32;
-            u_ext = (ui16)(cond1 ? (uvlc_entry & 0xF) : 0);
+            u_ext = (ui16)(cond1 ? (vlc_val & 0xF) : 0);
             vlc_val = rev_advance64(&vlc, cond1 ? 4 : 0);
             u_q1 = (ui16)(u_q1 + (u_ext << 2));
             sp[3] = u_q1;