From: Christophe Gisquet <christophe.gisquet@gmail.com>
To: ffmpeg-devel@ffmpeg.org
Subject: [FFmpeg-devel] [PATCH 1/2] Expose and start using skip_remaining
Date: Thu, 7 Sep 2023 21:27:20 +0200
Message-ID: <20230907192721.50459-2-christophe.gisquet@gmail.com> (raw)
In-Reply-To: <20230907192721.50459-1-christophe.gisquet@gmail.com>
Bitstream readers sometimes have already checked there are enough
bits, and the check is redundant.
---
libavcodec/bitstream.h | 8 +++++---
libavcodec/bitstream_template.h | 22 +++++++++++-----------
libavcodec/get_bits.h | 1 +
3 files changed, 17 insertions(+), 14 deletions(-)
diff --git a/libavcodec/bitstream.h b/libavcodec/bitstream.h
index 35b7873b9c..dd043fb349 100644
--- a/libavcodec/bitstream.h
+++ b/libavcodec/bitstream.h
@@ -95,6 +95,7 @@
# define bits_peek_signed bits_peek_signed_le
# define bits_peek_signed_nz bits_peek_signed_nz_le
# define bits_skip bits_skip_le
+# define bits_skip_remaining bits_skip_remaining_le
# define bits_seek bits_seek_le
# define bits_align bits_align_le
# define bits_read_xbits bits_read_xbits_le
@@ -124,6 +125,7 @@
# define bits_peek_signed bits_peek_signed_be
# define bits_peek_signed_nz bits_peek_signed_nz_be
# define bits_skip bits_skip_be
+# define bits_skip_remaining bits_skip_remaining_be
# define bits_seek bits_seek_be
# define bits_align bits_align_be
# define bits_read_xbits bits_read_xbits_be
@@ -146,7 +148,7 @@
n = table[index].len; \
\
if (max_depth > 1 && n < 0) { \
- bits_skip(bc, bits); \
+ skip_remaining(bc, bits); \
\
nb_bits = -n; \
\
@@ -154,7 +156,7 @@
level = table[index].level; \
n = table[index].len; \
if (max_depth > 2 && n < 0) { \
- bits_skip(bc, nb_bits); \
+ skip_remaining(bc, nb_bits); \
nb_bits = -n; \
\
index = bits_peek(bc, nb_bits) + level; \
@@ -163,7 +165,7 @@
} \
} \
run = table[index].run; \
- bits_skip(bc, n); \
+ skip_remaining(bc, n); \
} while (0)
#endif /* AVCODEC_BITSTREAM_H */
diff --git a/libavcodec/bitstream_template.h b/libavcodec/bitstream_template.h
index 0308e3a924..3f90fc6a07 100644
--- a/libavcodec/bitstream_template.h
+++ b/libavcodec/bitstream_template.h
@@ -175,7 +175,7 @@ static inline uint64_t BS_FUNC(priv_val_show)(BSCTX *bc, unsigned int n)
#endif
}
-static inline void BS_FUNC(priv_skip_remaining)(BSCTX *bc, unsigned int n)
+static inline void BS_FUNC(skip_remaining)(BSCTX *bc, unsigned int n)
{
#ifdef BITSTREAM_TEMPLATE_LE
bc->bits >>= n;
@@ -192,7 +192,7 @@ static inline uint64_t BS_FUNC(priv_val_get)(BSCTX *bc, unsigned int n)
av_assert2(n > 0 && n < 64);
ret = BS_FUNC(priv_val_show)(bc, n);
- BS_FUNC(priv_skip_remaining)(bc, n);
+ BS_FUNC(skip_remaining)(bc, n);
return ret;
}
@@ -375,7 +375,7 @@ static inline int BS_FUNC(peek_signed)(BSCTX *bc, unsigned int n)
static inline void BS_FUNC(skip)(BSCTX *bc, unsigned int n)
{
if (n < bc->bits_valid)
- BS_FUNC(priv_skip_remaining)(bc, n);
+ BS_FUNC(skip_remaining)(bc, n);
else {
n -= bc->bits_valid;
bc->bits = 0;
@@ -389,7 +389,7 @@ static inline void BS_FUNC(skip)(BSCTX *bc, unsigned int n)
}
BS_FUNC(priv_refill_64)(bc);
if (n)
- BS_FUNC(priv_skip_remaining)(bc, n);
+ BS_FUNC(skip_remaining)(bc, n);
}
}
@@ -425,7 +425,7 @@ static inline int BS_FUNC(read_xbits)(BSCTX *bc, unsigned int n)
{
int32_t cache = BS_FUNC(peek)(bc, 32);
int sign = ~cache >> 31;
- BS_FUNC(priv_skip_remaining)(bc, n);
+ BS_FUNC(skip_remaining)(bc, n);
return ((((uint32_t)(sign ^ cache)) >> (32 - n)) ^ sign) - sign;
}
@@ -508,14 +508,14 @@ static inline int BS_FUNC(read_vlc)(BSCTX *bc, const VLCElem *table,
int n = table[idx].len;
if (max_depth > 1 && n < 0) {
- BS_FUNC(priv_skip_remaining)(bc, bits);
+ BS_FUNC(skip_remaining)(bc, bits);
code = BS_FUNC(priv_set_idx)(bc, code, &n, &nb_bits, table);
if (max_depth > 2 && n < 0) {
- BS_FUNC(priv_skip_remaining)(bc, nb_bits);
+ BS_FUNC(skip_remaining)(bc, nb_bits);
code = BS_FUNC(priv_set_idx)(bc, code, &n, &nb_bits, table);
}
}
- BS_FUNC(priv_skip_remaining)(bc, n);
+ BS_FUNC(skip_remaining)(bc, n);
return code;
}
@@ -534,17 +534,17 @@ static inline int BS_FUNC(read_vlc_multi)(BSCTX *bc, uint8_t *dst,
code = table[idx].sym;
n = table[idx].len;
if (max_depth > 1 && n < 0) {
- BS_FUNC(priv_skip_remaining)(bc, bits);
+ BS_FUNC(skip_remaining)(bc, bits);
code = BS_FUNC(priv_set_idx)(bc, code, &n, &nb_bits, table);
if (max_depth > 2 && n < 0) {
- BS_FUNC(priv_skip_remaining)(bc, nb_bits);
+ BS_FUNC(skip_remaining)(bc, nb_bits);
code = BS_FUNC(priv_set_idx)(bc, code, &n, &nb_bits, table);
}
}
AV_WN16(dst, code);
ret = n > 0;
}
- BS_FUNC(priv_skip_remaining)(bc, n);
+ BS_FUNC(skip_remaining)(bc, n);
return ret;
}
diff --git a/libavcodec/get_bits.h b/libavcodec/get_bits.h
index 0594e104bb..2e24632cb5 100644
--- a/libavcodec/get_bits.h
+++ b/libavcodec/get_bits.h
@@ -79,6 +79,7 @@ typedef BitstreamContext GetBitContext;
#define get_bits_left bits_left
#define skip_bits_long bits_skip
#define skip_bits bits_skip
+#define skip_remaining bits_skip_remaining
#define get_bits bits_read_nz
#define get_bitsz bits_read
#define get_bits_long bits_read
--
2.42.0
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next prev parent reply other threads:[~2023-09-07 19:27 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-09-07 19:27 [FFmpeg-devel] [PATCH 0/2] cached bistream: small improvements Christophe Gisquet
2023-09-07 19:27 ` Christophe Gisquet [this message]
2023-09-07 22:40 ` [FFmpeg-devel] [PATCH 1/2] Expose and start using skip_remaining Andreas Rheinhardt
2023-09-11 20:43 ` Christophe Gisquet
2023-09-07 19:27 ` [FFmpeg-devel] [PATCH 2/2] read_xbits: request fewer bits Christophe Gisquet
2023-09-07 22:48 ` Andreas Rheinhardt
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