Do not loose pts on stream properties changes.

It closes #2349.

modules/packetizer/flac.c

@@ -285,8 +285,9 @@ static block_t *Packetize( decoder_t *p_dec, block_t **pp_block )
             if( p_sys->i_rate != p_dec->fmt_out.audio.i_rate )
             {
                 p_dec->fmt_out.audio.i_rate = p_sys->i_rate;
+                const mtime_t i_end_date = date_Get( &p_sys->end_date );
                 date_Init( &p_sys->end_date, p_sys->i_rate, 1 );
-                date_Set( &p_sys->end_date, p_sys->i_pts );
+                date_Set( &p_sys->end_date, i_end_date );
             }
             p_sys->i_state = STATE_NEXT_SYNC;
             p_sys->i_frame_size = p_sys->b_stream_info && p_sys->stream_info.min_framesize > 0 ?

modules/packetizer/mlp.c

@@ -302,8 +302,9 @@ static block_t *Packetize( decoder_t *p_dec, block_t **pp_block )
                 msg_Info( p_dec, "MLP channels: %d samplerate: %d",
                           p_sys->mlp.i_channels, p_sys->mlp.i_rate );
 
+                const mtime_t i_end_date = date_Get( &p_sys->end_date );
                 date_Init( &p_sys->end_date, p_sys->mlp.i_rate, 1 );
-                date_Set( &p_sys->end_date, p_sys->i_pts );
+                date_Set( &p_sys->end_date, i_end_date );
             }
 
             p_dec->fmt_out.audio.i_rate     = p_sys->mlp.i_rate;

modules/packetizer/mpeg4audio.c

@@ -1205,8 +1205,9 @@ static void SetupOutput( decoder_t *p_dec, block_t *p_block )
         msg_Info( p_dec, "AAC channels: %d samplerate: %d",
                   p_sys->i_channels, p_sys->i_rate );
 
+        const mtime_t i_end_date = date_Get( &p_sys->end_date );
         date_Init( &p_sys->end_date, p_sys->i_rate, 1 );
-        date_Set( &p_sys->end_date, p_sys->i_pts );
+        date_Set( &p_sys->end_date, i_end_date );
     }
 
     p_dec->fmt_out.audio.i_rate     = p_sys->i_rate;