[FFmpeg-devel] [PATCH] avcodec/get_bits: unbreak get_bits_le() with cached reader
Paul B Mahol
onemda at gmail.com
Tue Mar 26 12:13:30 EET 2019
Signed-off-by: Paul B Mahol <onemda at gmail.com>
---
libavcodec/get_bits.h | 82 +++++++++++++++++++++++++++++------------
libavcodec/utvideodec.c | 4 +-
2 files changed, 60 insertions(+), 26 deletions(-)
diff --git a/libavcodec/get_bits.h b/libavcodec/get_bits.h
index c2f267186e..c4ab607744 100644
--- a/libavcodec/get_bits.h
+++ b/libavcodec/get_bits.h
@@ -226,34 +226,32 @@ static inline int get_bits_count(const GetBitContext *s)
}
#if CACHED_BITSTREAM_READER
-static inline void refill_32(GetBitContext *s)
+static inline void refill_32(GetBitContext *s, int is_le)
{
#if !UNCHECKED_BITSTREAM_READER
if (s->index >> 3 >= s->buffer_end - s->buffer)
return;
#endif
-#ifdef BITSTREAM_READER_LE
+ if (is_le)
s->cache = (uint64_t)AV_RL32(s->buffer + (s->index >> 3)) << s->bits_left | s->cache;
-#else
+ else
s->cache = s->cache | (uint64_t)AV_RB32(s->buffer + (s->index >> 3)) << (32 - s->bits_left);
-#endif
s->index += 32;
s->bits_left += 32;
}
-static inline void refill_64(GetBitContext *s)
+static inline void refill_64(GetBitContext *s, int is_le)
{
#if !UNCHECKED_BITSTREAM_READER
if (s->index >> 3 >= s->buffer_end - s->buffer)
return;
#endif
-#ifdef BITSTREAM_READER_LE
+ if (is_le)
s->cache = AV_RL64(s->buffer + (s->index >> 3));
-#else
+ else
s->cache = AV_RB64(s->buffer + (s->index >> 3));
-#endif
s->index += 64;
s->bits_left = 64;
}
@@ -385,7 +383,11 @@ static inline unsigned int get_bits(GetBitContext *s, int n)
av_assert2(n>0 && n<=32);
if (n > s->bits_left) {
- refill_32(s);
+#ifdef BITSTREAM_READER_LE
+ refill_32(s, 1);
+#else
+ refill_32(s, 0);
+#endif
if (s->bits_left < 32)
s->bits_left = n;
}
@@ -420,7 +422,7 @@ static inline unsigned int get_bits_le(GetBitContext *s, int n)
#if CACHED_BITSTREAM_READER
av_assert2(n>0 && n<=32);
if (n > s->bits_left) {
- refill_32(s);
+ refill_32(s, 1);
if (s->bits_left < 32)
s->bits_left = n;
}
@@ -446,7 +448,11 @@ static inline unsigned int show_bits(GetBitContext *s, int n)
register unsigned int tmp;
#if CACHED_BITSTREAM_READER
if (n > s->bits_left)
- refill_32(s);
+#ifdef BITSTREAM_READER_LE
+ refill_32(s, 1);
+#else
+ refill_32(s, 0);
+#endif
tmp = show_val(s, n);
#else
@@ -474,7 +480,11 @@ static inline void skip_bits(GetBitContext *s, int n)
n -= skip;
s->index += skip;
}
- refill_64(s);
+#ifdef BITSTREAM_READER_LE
+ refill_64(s, 1);
+#else
+ refill_64(s, 0);
+#endif
if (n)
skip_remaining(s, n);
}
@@ -489,7 +499,11 @@ static inline unsigned int get_bits1(GetBitContext *s)
{
#if CACHED_BITSTREAM_READER
if (!s->bits_left)
- refill_64(s);
+#ifdef BITSTREAM_READER_LE
+ refill_64(s, 1);
+#else
+ refill_64(s, 0);
+#endif
#ifdef BITSTREAM_READER_LE
return get_val(s, 1, 1);
@@ -605,16 +619,8 @@ static inline int check_marker(void *logctx, GetBitContext *s, const char *msg)
return bit;
}
-/**
- * Initialize GetBitContext.
- * @param buffer bitstream buffer, must be AV_INPUT_BUFFER_PADDING_SIZE bytes
- * larger than the actual read bits because some optimized bitstream
- * readers read 32 or 64 bit at once and could read over the end
- * @param bit_size the size of the buffer in bits
- * @return 0 on success, AVERROR_INVALIDDATA if the buffer_size would overflow.
- */
-static inline int init_get_bits(GetBitContext *s, const uint8_t *buffer,
- int bit_size)
+static inline int init_get_bits_xe(GetBitContext *s, const uint8_t *buffer,
+ int bit_size, int is_le)
{
int buffer_size;
int ret = 0;
@@ -634,12 +640,32 @@ static inline int init_get_bits(GetBitContext *s, const uint8_t *buffer,
s->index = 0;
#if CACHED_BITSTREAM_READER
- refill_64(s);
+ s->cache = 0;
+ s->bits_left = 0;
+ refill_64(s, is_le);
#endif
return ret;
}
+/**
+ * Initialize GetBitContext.
+ * @param buffer bitstream buffer, must be AV_INPUT_BUFFER_PADDING_SIZE bytes
+ * larger than the actual read bits because some optimized bitstream
+ * readers read 32 or 64 bit at once and could read over the end
+ * @param bit_size the size of the buffer in bits
+ * @return 0 on success, AVERROR_INVALIDDATA if the buffer_size would overflow.
+ */
+static inline int init_get_bits(GetBitContext *s, const uint8_t *buffer,
+ int bit_size)
+{
+#ifdef BITSTREAM_READER_LE
+ return init_get_bits_xe(s, buffer, bit_size, 1);
+#else
+ return init_get_bits_xe(s, buffer, bit_size, 0);
+#endif
+}
+
/**
* Initialize GetBitContext.
* @param buffer bitstream buffer, must be AV_INPUT_BUFFER_PADDING_SIZE bytes
@@ -656,6 +682,14 @@ static inline int init_get_bits8(GetBitContext *s, const uint8_t *buffer,
return init_get_bits(s, buffer, byte_size * 8);
}
+static inline int init_get_bits8_le(GetBitContext *s, const uint8_t *buffer,
+ int byte_size)
+{
+ if (byte_size > INT_MAX / 8 || byte_size < 0)
+ byte_size = -1;
+ return init_get_bits_xe(s, buffer, byte_size * 8, 1);
+}
+
static inline const uint8_t *align_get_bits(GetBitContext *s)
{
int n = -get_bits_count(s) & 7;
diff --git a/libavcodec/utvideodec.c b/libavcodec/utvideodec.c
index 3891df3570..d5af9d53a8 100644
--- a/libavcodec/utvideodec.c
+++ b/libavcodec/utvideodec.c
@@ -258,11 +258,11 @@ static int decode_plane(UtvideoContext *c, int plane_no,
GetBitContext cbit, pbit;
uint8_t *dest, *p;
- ret = init_get_bits8(&cbit, c->control_stream[plane_no][slice], c->control_stream_size[plane_no][slice]);
+ ret = init_get_bits8_le(&cbit, c->control_stream[plane_no][slice], c->control_stream_size[plane_no][slice]);
if (ret < 0)
return ret;
- ret = init_get_bits8(&pbit, c->packed_stream[plane_no][slice], c->packed_stream_size[plane_no][slice]);
+ ret = init_get_bits8_le(&pbit, c->packed_stream[plane_no][slice], c->packed_stream_size[plane_no][slice]);
if (ret < 0)
return ret;
--
2.17.1
More information about the ffmpeg-devel
mailing list