PS: fix length computation

Should close #9412
Ref #7303 #8180 #7889 #10123 #2608

(cherry picked from commit 2d8e53ac7e404e4ba1b68d70112d991e4adea0a1)
(cherry picked from commit 63a3b568ad2b49778f73d9d8fbec8e281b5f1291)
Signed-off-by: Jean-Baptiste Kempf <jb@videolan.org>

modules/demux/ps.c

@@ -258,7 +258,7 @@ static void FindLength( demux_t *p_demux )
         stream_Seek( p_demux->s, i_size - i_end );
 
         i = 0;
-        while( vlc_object_alive (p_demux) && i < 40 && Demux2( p_demux, true ) > 0 ) i++;
+        while( vlc_object_alive (p_demux) && i < 400 && Demux2( p_demux, true ) > 0 ) i++;
         if( i_current_pos >= 0 ) stream_Seek( p_demux->s, i_current_pos );
     }
 
@@ -266,7 +266,7 @@ static void FindLength( demux_t *p_demux )
     for( int i = 0; i < PS_TK_COUNT; i++ )
     {
         ps_track_t *tk = &p_sys->tk[i];
-        if( tk->i_first_pts >= 0 && tk->i_last_pts > 0 &&
+        if( tk->i_last_pts > 0 &&
             tk->i_last_pts > tk->i_first_pts )
         {
             int64_t i_length = (int64_t)tk->i_last_pts - tk->i_first_pts;