avcodec/dcahuff: Always use three bits for transition mode VLCs

It increases the size of one VLC from two to three bits, thereby
requiring four more VLCEntries (16 bytes .bss), but it allows to
inline the number of bits used when reading them.

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>

libavcodec/dca_core.c

@@ -457,7 +457,7 @@ static int parse_subframe_header(DCACoreDecoder *s, int sf,
             for (band = 0; band < s->subband_vq_start[ch]; band++)
                 if (s->bit_allocation[ch][band])
                     s->transition_mode[sf][ch][band] = get_vlc2(&s->gb, ff_dca_vlc_transition_mode[sel].table,
-                                                                ff_dca_vlc_transition_mode[sel].bits,1);
+                                                                DCA_TMODE_VLC_BITS, 1);
         }
     }
 

libavcodec/dcahuff.c

@@ -29,7 +29,6 @@
 #include "put_bits.h"
 
 #define TMODE_COUNT 4
-static const uint8_t tmode_vlc_bits[TMODE_COUNT] = { 3, 3, 3, 2 };
 static const uint16_t tmode_codes[TMODE_COUNT][4] = {
     { 0x0000, 0x0002, 0x0006, 0x0007 },
     { 0x0002, 0x0006, 0x0007, 0x0000 },
@@ -1252,7 +1251,7 @@ VLC     ff_dca_vlc_rsd;
 
 av_cold void ff_dca_init_vlcs(void)
 {
-    static VLCElem dca_table[30214];
+    static VLCElem dca_table[30218];
     unsigned offset = 0;
     int i, j;
 
@@ -1277,7 +1276,7 @@ av_cold void ff_dca_init_vlcs(void)
                      scales_bits[i], scales_codes[i]);
 
     for (unsigned i = 0; i < FF_ARRAY_ELEMS(ff_dca_vlc_transition_mode); i++)
-        DCA_INIT_VLC(ff_dca_vlc_transition_mode[i], tmode_vlc_bits[i], 4,
+        DCA_INIT_VLC(ff_dca_vlc_transition_mode[i], DCA_TMODE_VLC_BITS, 4,
                      tmode_bits[i], tmode_codes[i]);
 
     for (i = 0; i < DCA_CODE_BOOKS; i++) {

libavcodec/dcahuff.h

@@ -40,6 +40,7 @@ typedef struct DCAVLC {
 } DCAVLC;
 
 extern DCAVLC   ff_dca_vlc_bit_allocation;
+#define DCA_TMODE_VLC_BITS 3
 extern VLC  ff_dca_vlc_transition_mode[4];
 extern DCAVLC   ff_dca_vlc_scale_factor;
 extern DCAVLC   ff_dca_vlc_quant_index[DCA_CODE_BOOKS];