avcodec/imc: Make Huffman tables smaller

The IMC decoder uses Huffman tables which are created at runtime from
length tables of type uint8_t and code tables of type uint16_t together
with an implicit symbols table (i.e. symbol[i] == i). This commit
changes this: All three tables are subjected to the same permutation to
order the codes from left to right in the tree; afterwards the codes can
be omitted because they are easily computable at runtime from the
lengths, whereas the symbols need to be explicitly coded now. But said
symbols fit into an uint8_t, so one saves space.

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

2 files changed, 37 insertions, 36 deletions

diff --git a/libavcodec/imc.c b/libavcodec/imc.c
index 70ad5b1dbd..5a1649ab62 100644
--- a/libavcodec/imc.c
+++ b/libavcodec/imc.c
@@ -239,9 +239,10 @@ static av_cold int imc_decode_init(AVCodecContext *avctx)
         for (j = 0; j < 4; j++) {
             huffman_vlc[i][j].table = &vlc_tables[vlc_offsets[i * 4 + j]];
             huffman_vlc[i][j].table_allocated = vlc_offsets[i * 4 + j + 1] - vlc_offsets[i * 4 + j];
-            init_vlc(&huffman_vlc[i][j], IMC_VLC_BITS, imc_huffman_sizes[i],
-                     imc_huffman_lens[i][j], 1, 1,
-                     imc_huffman_bits[i][j], 2, 2, INIT_VLC_USE_NEW_STATIC);
+            ff_init_vlc_from_lengths(&huffman_vlc[i][j], IMC_VLC_BITS, imc_huffman_sizes[i],
+                                     imc_huffman_lens[i][j], 1,
+                                     imc_huffman_syms[i][j], 1, 1,
+                                     0, INIT_VLC_USE_NEW_STATIC, NULL);
         }
     }
 
diff --git a/libavcodec/imcdata.h b/libavcodec/imcdata.h
index 64e7c7185e..46037bd555 100644
--- a/libavcodec/imcdata.h
+++ b/libavcodec/imcdata.h
@@ -114,55 +114,55 @@ static const uint8_t imc_huffman_sizes[4] = {
 
 static const uint8_t imc_huffman_lens[4][4][18] = {
     {
-        { 16, 15, 13, 11,  8,  5,  3,  1,  2,  4,  6,  9, 10, 12, 14, 16,  7,  0 },
-        { 10,  8,  7,  6,  4,  4,  3,  2,  2,  3,  4,  6,  7,  9, 11, 11,  7,  0 },
-        { 15, 15, 14, 11,  8,  6,  4,  2,  1,  4,  5,  7,  9, 10, 12, 13,  4,  0 },
-        { 13, 11, 10,  8,  6,  4,  2,  2,  2,  3,  5,  7,  9, 12, 15, 15, 14,  0 },
+        { 1,  2,  5,  6, 11, 12, 15, 16, 16, 14, 13, 10,  9,  8,  7,  4,  3 },
+        { 2,  3,  3,  4,  4,  4,  6,  6,  7,  7,  7,  8,  9, 10, 11, 11,  2 },
+        { 1,  4,  4,  7,  9, 10, 12, 15, 15, 14, 13, 11,  8,  6,  5,  4,  2 },
+        { 2,  2,  4,  8,  9, 14, 15, 15, 13, 12, 11, 10,  7,  6,  5,  3,  2 },
     },
     {
-        { 14, 12, 10,  8,  7,  4,  2,  2,  2,  3,  5,  7,  9, 11, 13, 14,  7,  0 },
-        { 14, 13, 11,  8,  6,  4,  3,  2,  2,  3,  5,  7,  9, 10, 12, 14,  3,  0 },
-        { 13, 12, 10,  7,  5,  4,  3,  2,  2,  3,  4,  6,  8,  9, 11, 13,  4,  0 },
-        { 13, 12, 10,  7,  5,  4,  3,  2,  2,  3,  4,  6,  8,  9, 11, 13,  4,  0 },
+        { 2,  2,  3,  4,  7,  7, 10, 11, 12, 14, 14, 13,  9,  8,  7,  5,  2 },
+        { 2,  3, 14, 14, 13, 12, 11, 10,  9,  8,  7,  6,  5,  4,  3,  3,  2 },
+        { 2,  3,  3,  4,  4,  5,  7,  9, 11, 12, 13, 13, 10,  8,  6,  4,  2 },
+        { 2,  3,  3,  4,  4,  5,  7,  9, 11, 12, 13, 13, 10,  8,  6,  4,  2 },
     },
     {
-        { 16, 14, 12, 10,  8,  5,  3,  1,  2,  4,  7,  9, 11, 13, 15, 17,  6, 17 },
-        { 15, 13, 11,  8,  6,  4,  2,  2,  2,  3,  5,  7, 10, 12, 14, 16,  9, 16 },
-        { 14, 12, 11,  9,  8,  6,  3,  1,  2,  5,  7, 10, 13, 15, 16, 17,  4, 17 },
-        { 16, 14, 12,  9,  7,  5,  2,  2,  2,  3,  4,  6,  8, 11, 13, 15, 10, 16 },
+        { 3,  5,  8,  9, 12, 15, 17, 17, 16, 14, 13, 11, 10,  7,  6,  4,  2,  1 },
+        { 4,  7,  8, 10, 11, 12, 15, 16, 16, 14, 13,  9,  6,  5,  3,  2,  2,  2 },
+        { 4,  5,  6,  7, 12, 13, 17, 17, 16, 15, 14, 11, 10,  9,  8,  3,  2,  1 },
+        { 2,  5,  7,  8, 14, 15, 16, 16, 13, 12, 11, 10,  9,  6,  4,  3,  2,  2 },
     },
     {
-        { 13, 11, 10,  8,  7,  5,  2,  2,  2,  4,  6,  9, 12, 14, 15, 16,  3, 16 },
-        { 11, 11, 10,  9,  8,  7,  5,  4,  3,  3,  3,  3,  3,  3,  4,  5,  6,  5 },
-        {  9,  9,  7,  6,  5,  4,  3,  3,  2,  3,  4,  5,  4,  5,  5,  6,  8,  6 },
-        { 13, 12, 10,  8,  5,  3,  3,  2,  2,  3,  4,  7,  9, 11, 14, 15,  6, 15 },
+        { 2,  4,  7,  9, 10, 12, 13, 15, 16, 16, 14, 11,  8,  6,  5,  3,  2,  2 },
+        { 3,  5,  5,  7, 10, 11, 11,  9,  8,  6,  5,  4,  4,  3,  3,  3,  3,  3 },
+        { 5,  8,  9,  9,  7,  6,  6,  6,  5,  5,  5,  4,  4,  4,  3,  3,  3,  2 },
+        { 2,  3,  5,  7,  8, 11, 12, 13, 15, 15, 14, 10,  9,  6,  4,  3,  3,  2 },
     }
 };
 
-static const uint16_t imc_huffman_bits[4][4][18] = {
+static const uint8_t imc_huffman_syms[4][4][18] = {
     {
-        { 0xCC32, 0x6618, 0x1987, 0x0660, 0x00CD, 0x0018, 0x0007, 0x0000, 0x0002, 0x000D, 0x0032, 0x0199, 0x0331, 0x0CC2, 0x330D, 0xCC33, 0x0067, 0x0000 },
-        { 0x02FE, 0x00BE, 0x005E, 0x002D, 0x000A, 0x0009, 0x0003, 0x0003, 0x0000, 0x0002, 0x0008, 0x002C, 0x005D, 0x017E, 0x05FE, 0x05FF, 0x005C, 0x0000 },
-        { 0x5169, 0x5168, 0x28B5, 0x0517, 0x00A3, 0x0029, 0x0008, 0x0003, 0x0000, 0x0009, 0x0015, 0x0050, 0x0144, 0x028A, 0x0A2C, 0x145B, 0x000B, 0x0000 },
-        { 0x1231, 0x048D, 0x0247, 0x0090, 0x0025, 0x0008, 0x0001, 0x0003, 0x0000, 0x0005, 0x0013, 0x0049, 0x0122, 0x0919, 0x48C3, 0x48C2, 0x2460, 0x0000 },
+        {  7,  8,  5, 10,  3, 13,  1,  0, 15, 14,  2, 12, 11,  4, 16,  9,  6 },
+        {  8,  9,  6, 10,  5,  4, 11,  3, 16, 12,  2,  1, 13,  0, 14, 15,  7 },
+        {  8,  6,  9, 11, 12, 13, 14,  1,  0,  2, 15,  3,  4,  5, 10, 16,  7 },
+        {  8,  6,  5,  3, 12, 16, 15, 14,  0, 13,  1,  2, 11,  4, 10,  9,  7 },
     },
     {
-        { 0x2D1D, 0x0B46, 0x02D0, 0x00B5, 0x0059, 0x000A, 0x0003, 0x0001, 0x0000, 0x0004, 0x0017, 0x005B, 0x0169, 0x05A2, 0x168F, 0x2D1C, 0x0058, 0x0000 },
-        { 0x1800, 0x0C01, 0x0301, 0x0061, 0x0019, 0x0007, 0x0004, 0x0003, 0x0000, 0x0005, 0x000D, 0x0031, 0x00C1, 0x0181, 0x0601, 0x1801, 0x0002, 0x0000 },
-        { 0x1556, 0x0AAA, 0x02AB, 0x0054, 0x0014, 0x000B, 0x0002, 0x0003, 0x0000, 0x0003, 0x0008, 0x002B, 0x00AB, 0x0154, 0x0554, 0x1557, 0x0009, 0x0000 },
-        { 0x1556, 0x0AAA, 0x02AB, 0x0054, 0x0014, 0x000B, 0x0002, 0x0003, 0x0000, 0x0003, 0x0008, 0x002B, 0x00AB, 0x0154, 0x0554, 0x1557, 0x0009, 0x0000 },
+        {  8,  7,  9,  5, 16,  4,  2, 13,  1, 15,  0, 14, 12,  3, 11, 10,  6 },
+        {  8, 16,  0, 15,  1, 14,  2, 13, 12,  3, 11,  4, 10,  5,  6,  9,  7 },
+        {  8,  6,  9, 10, 16,  4,  3, 13, 14,  1,  0, 15,  2, 12, 11,  5,  7 },
+        {  8,  6,  9, 10, 16,  4,  3, 13, 14,  1,  0, 15,  2, 12, 11,  5,  7 },
     },
     {
-        { 0x2993, 0x0A65, 0x0298, 0x00A7, 0x0028, 0x0004, 0x0000, 0x0001, 0x0001, 0x0003, 0x0015, 0x0052, 0x014D, 0x0533, 0x14C8, 0x5324, 0x000B, 0x5325 },
-        { 0x09B8, 0x026F, 0x009A, 0x0012, 0x0005, 0x0000, 0x0001, 0x0002, 0x0003, 0x0001, 0x0003, 0x0008, 0x004C, 0x0136, 0x04DD, 0x1373, 0x0027, 0x1372 },
-        { 0x0787, 0x01E0, 0x00F1, 0x003D, 0x001F, 0x0006, 0x0001, 0x0001, 0x0001, 0x0002, 0x000E, 0x0079, 0x03C2, 0x0F0D, 0x1E19, 0x3C30, 0x0000, 0x3C31 },
-        { 0x4B06, 0x12C0, 0x04B1, 0x0097, 0x0024, 0x0008, 0x0002, 0x0003, 0x0000, 0x0003, 0x0005, 0x0013, 0x004A, 0x0259, 0x0961, 0x2582, 0x012D, 0x4B07 },
+        {  6,  5,  4, 11,  2, 14, 15, 17,  0,  1, 13, 12,  3, 10, 16,  9,  8,  7 },
+        {  5, 11,  3, 12,  2, 13,  0, 17, 15, 14,  1, 16,  4, 10,  9,  6,  7,  8 },
+        { 16,  9,  5, 10,  1, 12, 15, 17, 14, 13,  0,  2, 11,  3,  4,  6,  8,  7 },
+        {  8,  5,  4, 12,  1, 15,  0, 17, 14,  2, 13, 16,  3, 11, 10,  9,  6,  7 },
     },
     {
-        { 0x0A5A, 0x0297, 0x014A, 0x0053, 0x0028, 0x000B, 0x0003, 0x0000, 0x0002, 0x0004, 0x0015, 0x00A4, 0x052C, 0x14B7, 0x296C, 0x52DB, 0x0003, 0x52DA },
-        { 0x0193, 0x0192, 0x00C8, 0x0065, 0x0033, 0x0018, 0x0007, 0x0004, 0x0000, 0x0004, 0x0005, 0x0007, 0x0006, 0x0003, 0x0005, 0x0005, 0x000D, 0x0004 },
-        { 0x0012, 0x0013, 0x0005, 0x0003, 0x0000, 0x0003, 0x0005, 0x0004, 0x0003, 0x0003, 0x0005, 0x0005, 0x0004, 0x0004, 0x0003, 0x0005, 0x0008, 0x0004 },
-        { 0x0D66, 0x06B2, 0x01AD, 0x006A, 0x000C, 0x0005, 0x0004, 0x0000, 0x0003, 0x0002, 0x0007, 0x0034, 0x00D7, 0x0358, 0x1ACF, 0x359C, 0x001B, 0x359D },
+        {  7,  9,  4, 11,  2, 12,  0, 14, 17, 15, 13,  1,  3, 10,  5, 16,  8,  6 },
+        {  8, 17, 15,  5,  2,  1,  0,  3,  4, 16,  6,  7, 14, 13,  9, 10, 12, 11 },
+        {  4, 16,  0,  1,  2,  3, 17, 15, 14, 13, 11,  5, 12, 10,  9,  7,  6,  8 },
+        {  7,  9,  4, 11,  3, 13,  1,  0, 15, 17, 14,  2, 12, 16, 10,  6,  5,  8 },
     }
 };