[vlc-commits] access: dvdnav: skip cell on lost VOBU syncro

[Francois Cartegnie]

vlc | branch: master | Francois Cartegnie <fcvlcdev at free.fr> | Fri Feb 21 15:59:13 2020 +0100| [601cac14a6d2ac34246f8111d34025c6ff788f8e] | committer: Francois Cartegnie

access: dvdnav: skip cell on lost VOBU syncro

Corrupted titles for dvdread fun

> http://git.videolan.org/gitweb.cgi/vlc.git/?a=commit;h=601cac14a6d2ac34246f8111d34025c6ff788f8e
---

 modules/access/dvdread.c | 49 ++++++++++++++++++++++++++++++------------------
 1 file changed, 31 insertions(+), 18 deletions(-)

diff --git a/modules/access/dvdread.c b/modules/access/dvdread.c
index 109a529dd8..65d087c330 100644
--- a/modules/access/dvdread.c
+++ b/modules/access/dvdread.c
@@ -1167,26 +1167,39 @@ static void DvdReadHandleDSI( demux_t *p_demux, uint8_t *p_data )
 {
     demux_sys_t *p_sys = p_demux->p_sys;
 
-    navRead_DSI( &p_sys->dsi_pack, &p_data[DSI_START_BYTE] );
-
-    /*
-     * Determine where we go next.  These values are the ones we mostly
-     * care about.
-     */
-    p_sys->i_cur_block = p_sys->dsi_pack.dsi_gi.nv_pck_lbn;
-    p_sys->i_pack_len = p_sys->dsi_pack.dsi_gi.vobu_ea;
-
+    /* Check we are really on a DSI packet
+     * http://www.mpucoder.com/DVD/dsi_pkt.html
+     * Some think it's funny to fill with 0x42 */
+    const uint8_t dsiheader[7] = { 0x00, 0x00, 0x01, 0xbf, 0x03, 0xfa, 0x01 };
+    if(!memcmp(&p_data[DSI_START_BYTE-7], dsiheader, 7))
+    {
+        navRead_DSI( &p_sys->dsi_pack, &p_data[DSI_START_BYTE] );
 
-    /*
-     * If we're not at the end of this cell, we can determine the next
-     * VOBU to display using the VOBU_SRI information section of the
-     * DSI.  Using this value correctly follows the current angle,
-     * avoiding the doubled scenes in The Matrix, and makes our life
-     * really happy.
-     */
+        /*
+         * Determine where we go next.  These values are the ones we mostly
+        * care about.
+        */
+        p_sys->i_cur_block = p_sys->dsi_pack.dsi_gi.nv_pck_lbn;
+        p_sys->i_pack_len = p_sys->dsi_pack.dsi_gi.vobu_ea;
 
-    p_sys->i_next_vobu = p_sys->i_cur_block +
-        ( p_sys->dsi_pack.vobu_sri.next_vobu & 0x7fffffff );
+        /*
+        * If we're not at the end of this cell, we can determine the next
+        * VOBU to display using the VOBU_SRI information section of the
+        * DSI.  Using this value correctly follows the current angle,
+        * avoiding the doubled scenes in The Matrix, and makes our life
+        * really happy.
+        */
+
+        p_sys->i_next_vobu = p_sys->i_cur_block +
+            ( p_sys->dsi_pack.vobu_sri.next_vobu & 0x7fffffff );
+    }
+    else
+    {
+        /* resync after decoy/corrupted titles */
+        msg_Warn(p_demux, "Invalid DSI packet in VOBU %d found, skipping Cell %d / %d",
+                 p_sys->i_next_vobu, p_sys->i_cur_cell, p_sys->i_title_end_cell);
+        p_sys->dsi_pack.vobu_sri.next_vobu = SRI_END_OF_CELL;
+    }
 
     if( p_sys->dsi_pack.vobu_sri.next_vobu != SRI_END_OF_CELL
         && p_sys->i_angle > 1 )