Check extended sync word for 16-bit LE and BE core streams to reduce
probability of alias sync detection. Previously sync word extension was
checked only for 14-bit streams.
This is sufficient to make the sample in ticket #4492 parse successfully.
The proper solution, however, would involve taking extension sub-stream
length into account by the parser.
---
libavcodec/dca_parser.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/libavcodec/dca_parser.c b/libavcodec/dca_parser.c
index 9797760..41658a5 100644
--- a/libavcodec/dca_parser.c
+++ b/libavcodec/dca_parser.c
@@ -38,7 +38,9 @@ typedef struct DCAParseContext {
#define IS_MARKER(state, i, buf, buf_size) \
((state == DCA_SYNCWORD_CORE_14B_LE && (i < buf_size - 2) && (buf[i + 1] &
0xF0) == 0xF0 && buf[i + 2] == 0x07) || \
(state == DCA_SYNCWORD_CORE_14B_BE && (i < buf_size - 2) && buf[i + 1]
== 0x07 && (buf[i + 2] & 0xF0) == 0xF0) || \
- state == DCA_SYNCWORD_CORE_LE || state == DCA_SYNCWORD_CORE_BE || state
== DCA_SYNCWORD_SUBSTREAM)
+ (state == DCA_SYNCWORD_CORE_LE && (i < buf_size - 2) && (buf[i + 2] &
0xFC) == 0xFC) || \
+ (state == DCA_SYNCWORD_CORE_BE && (i < buf_size - 1) && (buf[i + 1] &
0xFC) == 0xFC) || \
+ state == DCA_SYNCWORD_SUBSTREAM)
/**
* Find the end of the current frame in the bitstream.
--
2.1.4
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