[FFmpeg-cvslog] avformat/m4vdec: Fix detection of raw MPEG-4 ES Studio

Michael Niedermayer git at videolan.org
Sat Jun 16 01:30:47 EEST 2018


ffmpeg | branch: release/4.0 | Michael Niedermayer <michael at niedermayer.cc> | Sun Apr 29 23:56:14 2018 +0200| [7bc5d49c60af8d17f255600104c1e819fd97ce30] | committer: Michael Niedermayer

avformat/m4vdec: Fix detection of raw MPEG-4 ES Studio

Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
(cherry picked from commit 34dbdcfc20d69b7b67fd13112445cd05b9b5d979)
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=7bc5d49c60af8d17f255600104c1e819fd97ce30
---

 libavformat/m4vdec.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/libavformat/m4vdec.c b/libavformat/m4vdec.c
index 34d434f7d2..ebc7ab4f81 100644
--- a/libavformat/m4vdec.c
+++ b/libavformat/m4vdec.c
@@ -24,11 +24,14 @@
 
 #define VISUAL_OBJECT_START_CODE       0x000001b5
 #define VOP_START_CODE                 0x000001b6
+#define SLICE_STARTCODE      0x1B7
+#define EXT_STARTCODE        0x1B8
 
 static int mpeg4video_probe(AVProbeData *probe_packet)
 {
     uint32_t temp_buffer = -1;
     int VO = 0, VOL = 0, VOP = 0, VISO = 0, res = 0;
+    int res_main = 0;
     int i;
 
     for (i = 0; i < probe_packet->buf_size; i++) {
@@ -46,11 +49,19 @@ static int mpeg4video_probe(AVProbeData *probe_packet)
             VO++;
         else if (temp_buffer >= 0x120 && temp_buffer < 0x130)
             VOL++;
+        else if (temp_buffer == SLICE_STARTCODE || temp_buffer == EXT_STARTCODE)
+            res_main++;
         else if (!(0x1AF < temp_buffer && temp_buffer < 0x1B7) &&
                  !(0x1B9 < temp_buffer && temp_buffer < 0x1C4))
             res++;
     }
 
+    // res_main repesents the reserved codes within the "main" profile, they are
+    // added to the reserved ones if it appears that this is a "main" profile
+    // stream
+    if (res_main && 2*res_main < VOP)
+        res += res_main;
+
     if (VOP >= VISO && VOP >= VOL && VO >= VOL && VOL > 0 && res == 0)
         return VOP+VO > 4 ? AVPROBE_SCORE_EXTENSION : AVPROBE_SCORE_EXTENSION/2;
 



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