libmp4: fix 'mfhd' parsing

Signed-off-by: Jean-Baptiste Kempf <jb@videolan.org>
(cherry picked from commit 0b1b7516)
Signed-off-by: Jean-Baptiste Kempf <jb@videolan.org>

modules/demux/mp4/libmp4.c

@@ -483,6 +483,8 @@ static int MP4_ReadBox_mfhd(  stream_t *p_stream, MP4_Box_t *p_box )
 {
     MP4_READBOX_ENTER( MP4_Box_data_mfhd_t );
 
+    MP4_GETVERSIONFLAGS( p_box->data.p_mvhd );
+
     MP4_GET4BYTES( p_box->data.p_mfhd->i_sequence_number );
 
 #ifdef MP4_VERBOSE

modules/demux/mp4/libmp4.h

@@ -828,9 +828,10 @@ typedef struct
 
 typedef struct MP4_Box_data_mfhd_s
 {
-    uint32_t i_sequence_number;
+    uint8_t  i_version;
+    uint32_t i_flags;
 
-    uint8_t *p_vendor_extension;
+    uint32_t i_sequence_number;
 
 } MP4_Box_data_mfhd_t;