aes3: use VLC_TS_INVALID (refs #3135)

modules/codec/aes3.c

@@ -297,7 +297,7 @@ static block_t *Parse( decoder_t *p_dec, int *pi_frame_length, int *pi_bits,
     *pp_block = NULL; /* So the packet doesn't get re-sent */
 
     /* Date management */
-    if( p_block->i_pts > 0 &&
+    if( p_block->i_pts > VLC_TS_INVALID &&
         p_block->i_pts != date_Get( &p_sys->end_date ) )
     {
         date_Set( &p_sys->end_date, p_block->i_pts );