This is easily possible because ff_init_vlc_sparse() already transforms
both LE as well as BE codes to a normal form internally before
processing them further. This will be used in subsequent commits.
Signed-off-by: Andreas Rheinhardt
---
libavcodec/bitstream.c | 6 +++---
libavcodec/vlc.h | 29 +++--
2 files changed, 22 insertions(+), 13 deletions(-)
diff --git a/libavcodec/bitstream.c b/libavcodec/bitstream.c
index 95e5092b44..77c2b9ce05 100644
--- a/libavcodec/bitstream.c
+++ b/libavcodec/bitstream.c
@@ -182,7 +182,7 @@ static int build_table(VLC *vlc, int table_nb_bits, int
nb_codes,
j = code >> (32 - table_nb_bits);
nb = 1 << (table_nb_bits - n);
inc = 1;
-if (flags & INIT_VLC_LE) {
+if (flags & INIT_VLC_OUTPUT_LE) {
j = bitswap_32(code);
inc = 1 << n;
}
@@ -217,7 +217,7 @@ static int build_table(VLC *vlc, int table_nb_bits, int
nb_codes,
subtable_bits = FFMAX(subtable_bits, n);
}
subtable_bits = FFMIN(subtable_bits, table_nb_bits);
-j = (flags & INIT_VLC_LE) ? bitswap_32(code_prefix) >> (32 -
table_nb_bits) : code_prefix;
+j = (flags & INIT_VLC_OUTPUT_LE) ? bitswap_32(code_prefix) >> (32
- table_nb_bits) : code_prefix;
table[j][1] = -subtable_bits;
ff_dlog(NULL, "%4x: n=%d (subtable)\n",
j, codes[i].bits + table_nb_bits);
@@ -319,7 +319,7 @@ int ff_init_vlc_sparse(VLC *vlc_arg, int nb_bits, int
nb_codes,
av_free(buf); \
return AVERROR(EINVAL); \
} \
-if (flags & INIT_VLC_LE)\
+if (flags & INIT_VLC_INPUT_LE) \
buf[j].code = bitswap_32(buf[j].code); \
else\
buf[j].code <<= 32 - buf[j].bits; \
diff --git a/libavcodec/vlc.h b/libavcodec/vlc.h
index 42ccddf3fc..22d3e33485 100644
--- a/libavcodec/vlc.h
+++ b/libavcodec/vlc.h
@@ -51,26 +51,35 @@ int ff_init_vlc_sparse(VLC *vlc, int nb_bits, int nb_codes,
int flags);
void ff_free_vlc(VLC *vlc);
-#define INIT_VLC_LE 2
+/* If INIT_VLC_INPUT_LE is set, the LSB bit of the codes used to
+ * initialize the VLC table is the first bit to be read. */
+#define INIT_VLC_INPUT_LE 2
+/* If set the VLC is intended for a little endian bitstream reader. */
+#define INIT_VLC_OUTPUT_LE 8
+#define INIT_VLC_LE (INIT_VLC_INPUT_LE | INIT_VLC_OUTPUT_LE)
#define INIT_VLC_USE_NEW_STATIC 4
-#define INIT_VLC_SPARSE_STATIC(vlc, bits, a, b, c, d, e, f, g, h, i, j,
static_size) \
+#define INIT_CUSTOM_VLC_SPARSE_STATIC(vlc, bits, a, b, c, d, e, f, g, \
+ h, i, j, flags, static_size) \
do { \
static VLC_TYPE table[static_size][2]; \
(vlc)->table = table;\
(vlc)->table_allocated = static_size; \
ff_init_vlc_sparse(vlc, bits, a, b, c, d, e, f, g, h, i, j,\
-INIT_VLC_USE_NEW_STATIC); \
+ flags | INIT_VLC_USE_NEW_STATIC); \
} while (0)
+#define INIT_VLC_SPARSE_STATIC(vlc, bits, a, b, c, d, e, f, g, h, i, j,
static_size) \
+INIT_CUSTOM_VLC_SPARSE_STATIC(vlc, bits, a, b, c, d, e, f, g, \
+ h, i, j, 0, static_size)
+
#define INIT_LE_VLC_SPARSE_STATIC(vlc, bits, a, b, c, d, e, f, g, h, i, j,
static_size) \
-do { \
-static VLC_TYPE table[static_size][2]; \
-(vlc)->table = table;\
-(vlc)->table_allocated = static_size; \
-ff_init_vlc_sparse(vlc, bits, a, b, c, d, e, f, g, h, i, j,\
-INIT_VLC_USE_NEW_STATIC | INIT_VLC_LE);\
-} while (0)
+INIT_CUSTOM_VLC_SPARSE_STATIC(vlc, bits, a, b, c, d, e, f, g, \
+ h, i, j, INIT_VLC_LE, static_size)
+
+#define INIT_CUSTOM_VLC_STATIC(vlc, bits, a, b, c, d, e, f, g, flags,
static_size) \
+INIT_CUSTOM_VLC_SPARSE_STATIC(vlc, bits, a, b, c, d, e, f, g, \
+ NULL, 0, 0, flags, static_size)
#define INIT_VLC_STATIC(vlc, bits, a, b, c, d, e, f, g, static_size) \
