[FFmpeg-cvslog] dca_parser: Extend DTS core sync word and fix existing check
foo86
git at videolan.org
Tue May 12 12:15:56 CEST 2015
ffmpeg | branch: master | foo86 <foobaz86 at gmail.com> | Wed Apr 29 11:14:55 2015 +0300| [0670acc4f1c4ceb16968818a654e07a3f550a8c9] | committer: Luca Barbato
dca_parser: Extend DTS core sync word and fix existing check
The previous version checked for 14-bit streams and did not properly
work across buffer boundaries.
Use the 64-bit parser state to make extended sync word detection work
across buffer boundary and check the extended sync word for 16-bit LE
and BE core streams to reduce probability of alias sync detection.
Signed-off-by: Michael Niedermayer <michaelni at gmx.at>
Signed-off-by: Luca Barbato <lu_zero at gentoo.org>
> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=0670acc4f1c4ceb16968818a654e07a3f550a8c9
---
libavcodec/dca_parser.c | 48 +++++++++++++++++++++++++++--------------------
1 file changed, 28 insertions(+), 20 deletions(-)
diff --git a/libavcodec/dca_parser.c b/libavcodec/dca_parser.c
index 401402d..d827daa 100644
--- a/libavcodec/dca_parser.c
+++ b/libavcodec/dca_parser.c
@@ -32,13 +32,20 @@ typedef struct DCAParseContext {
uint32_t lastmarker;
int size;
int framesize;
- int hd_pos;
} 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)
+#define IS_CORE_MARKER(state) \
+ (((state & 0xFFFFFFFFF0FF) == (((uint64_t)DCA_SYNCWORD_CORE_14B_LE << 16) | 0xF007)) || \
+ ((state & 0xFFFFFFFFFFF0) == (((uint64_t)DCA_SYNCWORD_CORE_14B_BE << 16) | 0x07F0)) || \
+ ((state & 0xFFFFFFFF00FC) == (((uint64_t)DCA_SYNCWORD_CORE_LE << 16) | 0x00FC)) || \
+ ((state & 0xFFFFFFFFFC00) == (((uint64_t)DCA_SYNCWORD_CORE_BE << 16) | 0xFC00)))
+
+#define IS_EXSS_MARKER(state) ((state & 0xFFFFFFFF) == DCA_SYNCWORD_SUBSTREAM)
+
+#define IS_MARKER(state) (IS_CORE_MARKER(state) || IS_EXSS_MARKER(state))
+
+#define CORE_MARKER(state) ((state >> 16) & 0xFFFFFFFF)
+#define EXSS_MARKER(state) (state & 0xFFFFFFFF)
/**
* Find the end of the current frame in the bitstream.
@@ -48,24 +55,25 @@ static int dca_find_frame_end(DCAParseContext *pc1, const uint8_t *buf,
int buf_size)
{
int start_found, i;
- uint32_t state;
+ uint64_t state;
ParseContext *pc = &pc1->pc;
start_found = pc->frame_start_found;
- state = pc->state;
+ state = pc->state64;
i = 0;
if (!start_found) {
for (i = 0; i < buf_size; i++) {
state = (state << 8) | buf[i];
- if (IS_MARKER(state, i, buf, buf_size)) {
- if (pc1->lastmarker && state == pc1->lastmarker) {
+ if (IS_MARKER(state)) {
+ if (!pc1->lastmarker ||
+ pc1->lastmarker == CORE_MARKER(state) ||
+ pc1->lastmarker == DCA_SYNCWORD_SUBSTREAM) {
start_found = 1;
- i++;
- break;
- } else if (!pc1->lastmarker) {
- start_found = 1;
- pc1->lastmarker = state;
+ if (IS_EXSS_MARKER(state))
+ pc1->lastmarker = EXSS_MARKER(state);
+ else
+ pc1->lastmarker = CORE_MARKER(state);
i++;
break;
}
@@ -76,20 +84,20 @@ static int dca_find_frame_end(DCAParseContext *pc1, const uint8_t *buf,
for (; i < buf_size; i++) {
pc1->size++;
state = (state << 8) | buf[i];
- if (state == DCA_SYNCWORD_SUBSTREAM && !pc1->hd_pos)
- pc1->hd_pos = pc1->size;
- if (state == pc1->lastmarker && IS_MARKER(state, i, buf, buf_size)) {
+ if (IS_MARKER(state) &&
+ (pc1->lastmarker == CORE_MARKER(state) ||
+ pc1->lastmarker == DCA_SYNCWORD_SUBSTREAM)) {
if (pc1->framesize > pc1->size)
continue;
pc->frame_start_found = 0;
- pc->state = -1;
+ pc->state64 = -1;
pc1->size = 0;
- return i - 3;
+ return IS_EXSS_MARKER(state) ? i - 3 : i - 5;
}
}
}
pc->frame_start_found = start_found;
- pc->state = state;
+ pc->state64 = state;
return END_NOT_FOUND;
}
More information about the ffmpeg-cvslog
mailing list