[vlc-commits] demux: ts: workaround HLS dumps

[Francois Cartegnie]

vlc | branch: master | Francois Cartegnie <fcvlcdev at free.fr> | Tue Jul 24 22:26:21 2018 +0200| [3a794b149b9bf2bd2225f94c1cf05c4d5f31724c] | committer: Francois Cartegnie

demux: ts: workaround HLS dumps

Triggers duplicate packets on some boundaries
and artifacts. There's no way to tell if that's
a real discontinuity or duplicate packet.
At least we can discard false positives for duplicates.

> http://git.videolan.org/gitweb.cgi/vlc.git/?a=commit;h=3a794b149b9bf2bd2225f94c1cf05c4d5f31724c
---

 modules/demux/mpeg/ts.c     | 10 +++++++++-
 modules/demux/mpeg/ts_pid.c |  1 +
 modules/demux/mpeg/ts_pid.h |  2 ++
 3 files changed, 12 insertions(+), 1 deletion(-)

diff --git a/modules/demux/mpeg/ts.c b/modules/demux/mpeg/ts.c
index cb906be89f..18c4246268 100644
--- a/modules/demux/mpeg/ts.c
+++ b/modules/demux/mpeg/ts.c
@@ -2517,9 +2517,16 @@ static block_t * ProcessTSPacket( demux_t *p_demux, ts_pid_t *pid, block_t *p_pk
                          pid->i_pid, i_cc );
                 pid->i_cc = i_cc;
             }
-            else if( i_diff == 0 && pid->i_dup == 0 )
+            else if( i_diff == 0 && pid->i_dup == 0 &&
+                     !memcmp(pid->prevpktbytes, /* see comment below */
+                             &p_pkt->p_buffer[1], PREVPKTKEEPBYTES)  )
             {
                 /* Discard duplicated payload 2.4.3.3 */
+                /* Added previous pkt bytes comparison for
+                 * stupid HLS dumps/joined segments which are
+                 * triggering erroneous duplicates instead of discontinuity.
+                 * That should not need CRC or full payload as it should be
+                 * restarting with PSI packets */
                 pid->i_dup++;
                 block_Release( p_pkt );
                 return NULL;
@@ -2535,6 +2542,7 @@ static block_t * ProcessTSPacket( demux_t *p_demux, ts_pid_t *pid, block_t *p_pk
             }
             else pid->i_cc = i_cc;
         }
+        memcpy(pid->prevpktbytes, &p_pkt->p_buffer[1], PREVPKTKEEPBYTES);
     }
     else /* Ignore all 00 or 10 as in 2.4.3.3 CC counter must not be
             incremented in those cases, but there is humax inserting
diff --git a/modules/demux/mpeg/ts_pid.c b/modules/demux/mpeg/ts_pid.c
index 6d4b88cbd5..80d1a77ce0 100644
--- a/modules/demux/mpeg/ts_pid.c
+++ b/modules/demux/mpeg/ts_pid.c
@@ -175,6 +175,7 @@ static void PIDReset( ts_pid_t *pid )
     pid->i_dup      = 0;
     pid->i_flags    &= ~FLAG_SCRAMBLED;
     pid->type = TYPE_FREE;
+    memset(pid->prevpktbytes, 0, PREVPKTKEEPBYTES);
 }
 
 bool PIDSetup( demux_t *p_demux, ts_pid_type_t i_type, ts_pid_t *pid, ts_pid_t *p_parent )
diff --git a/modules/demux/mpeg/ts_pid.h b/modules/demux/mpeg/ts_pid.h
index 3a0e6bcffd..cf2c2a9c9d 100644
--- a/modules/demux/mpeg/ts_pid.h
+++ b/modules/demux/mpeg/ts_pid.h
@@ -49,6 +49,7 @@ enum
 
 #define SEEN(x) ((x)->i_flags & FLAG_SEEN)
 #define SCRAMBLED(x) ((x).i_flags & FLAG_SCRAMBLED)
+#define PREVPKTKEEPBYTES 16
 
 struct ts_pid_t
 {
@@ -58,6 +59,7 @@ struct ts_pid_t
     uint8_t     i_cc;   /* countinuity counter */
     uint8_t     i_dup;  /* duplicate counter */
     uint8_t     type;
+    uint8_t     prevpktbytes[PREVPKTKEEPBYTES];
 
     uint16_t    i_refcount;