[FFmpeg-cvslog] avformat/dv: consider a header match at byte 0 to count as detection of dv in probe

[Michael Niedermayer]

ffmpeg | branch: master | Michael Niedermayer <michaelni at gmx.at> | Sat Nov  9 17:31:35 2013 +0100| [ef8f293472851e77800bc6bd8004d7b27ec4a2bf] | committer: Michael Niedermayer

avformat/dv: consider a header match at byte 0 to count as detection of dv in probe

This reduces the amount of data needed to identify dv

Signed-off-by: Michael Niedermayer <michaelni at gmx.at>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=ef8f293472851e77800bc6bd8004d7b27ec4a2bf
---

 libavformat/dv.c |    8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/libavformat/dv.c b/libavformat/dv.c
index bc649e6..3590406 100644
--- a/libavformat/dv.c
+++ b/libavformat/dv.c
@@ -585,6 +585,7 @@ static int dv_probe(AVProbeData *p)
     unsigned state, marker_pos = 0;
     int i;
     int matches           = 0;
+    int firstmatch        = 0;
     int secondary_matches = 0;
 
     if (p->buf_size < 5)
@@ -597,8 +598,11 @@ static int dv_probe(AVProbeData *p)
             // should appear around every 12000 bytes, at least 10 per frame
             if ((state & 0xff07ff7f) == 0x1f07003f) {
                 secondary_matches++;
-                if ((state & 0xffffff7f) == 0x1f07003f)
+                if ((state & 0xffffff7f) == 0x1f07003f) {
                     matches++;
+                    if (!i)
+                        firstmatch = 1;
+                }
             }
             if (state == 0x003f0700 || state == 0xff3f0700)
                 marker_pos = i;
@@ -608,7 +612,7 @@ static int dv_probe(AVProbeData *p)
     }
 
     if (matches && p->buf_size / matches < 1024 * 1024) {
-        if (matches > 4 ||
+        if (matches > 4 || firstmatch ||
             (secondary_matches >= 10 &&
              p->buf_size / secondary_matches < 24000))
             // not max to avoid dv in mov to match