avcodec: add Newtek SpeedHQ decoder

This decoder can decode all existing SpeedHQ formats (SHQ0–5, 7, and 9),
including correct decoding of the alpha channel.

1080p is decoded in 142 fps on one core of my i7-4600U (2.1 GHz Haswell),
about evenly split between bitstream reader and IDCT. There is currently
no attempt at slice or frame threading, even though the format trivially
supports both.

NewTek very helpfully provided a full set of SHQ samples, as well as
source code for an SHQ2 encoder (not included) and assistance with
understanding some details of the format.

1 files changed, 4 insertions, 11 deletions

diff --git a/libavcodec/mpeg12.c b/libavcodec/mpeg12.c
index a61d45b..ab6c19c 100644
--- a/libavcodec/mpeg12.c
+++ b/libavcodec/mpeg12.c
@@ -67,20 +67,13 @@ static const uint8_t table_mb_btype[11][2] = {
     { 2, 5 }, // 0x1E MB_QUANT|MB_FOR|MB_BACK|MB_PAT
 };
 
-#define INIT_2D_VLC_RL(rl, static_size)\
-{\
-    static RL_VLC_ELEM rl_vlc_table[static_size];\
-    rl.rl_vlc[0] = rl_vlc_table;\
-    init_2d_vlc_rl(&rl, static_size);\
-}
-
-static av_cold void init_2d_vlc_rl(RLTable *rl, unsigned static_size)
+av_cold void ff_init_2d_vlc_rl(RLTable *rl, unsigned static_size, int flags)
 {
     int i;
     VLC_TYPE table[680][2] = {{0}};
     VLC vlc = { .table = table, .table_allocated = static_size };
     av_assert0(static_size <= FF_ARRAY_ELEMS(table));
-    init_vlc(&vlc, TEX_VLC_BITS, rl->n + 2, &rl->table_vlc[0][1], 4, 2, &rl->table_vlc[0][0], 4, 2, INIT_VLC_USE_NEW_STATIC);
+    init_vlc(&vlc, TEX_VLC_BITS, rl->n + 2, &rl->table_vlc[0][1], 4, 2, &rl->table_vlc[0][0], 4, 2, INIT_VLC_USE_NEW_STATIC | flags);
 
     for (i = 0; i < vlc.table_size; i++) {
         int code = vlc.table[i][0];
@@ -173,8 +166,8 @@ av_cold void ff_mpeg12_init_vlcs(void)
         ff_rl_init(&ff_rl_mpeg1, ff_mpeg12_static_rl_table_store[0]);
         ff_rl_init(&ff_rl_mpeg2, ff_mpeg12_static_rl_table_store[1]);
 
-        INIT_2D_VLC_RL(ff_rl_mpeg1, 680);
-        INIT_2D_VLC_RL(ff_rl_mpeg2, 674);
+        INIT_2D_VLC_RL(ff_rl_mpeg1, 680, 0);
+        INIT_2D_VLC_RL(ff_rl_mpeg2, 674, 0);
     }
 }