mpeg_audio packetizer: flush remaining data

vlc 1.mp3 --sout 2.mp3 && vlc 2.mp3 --sout 3.mp3
will now give identical 2.mp3 and 3.mp3

Refs: #3178

modules/codec/mpeg_audio.c

@@ -190,10 +190,9 @@ static block_t *DecodeBlock( decoder_t *p_dec, block_t **pp_block )
     uint8_t *p_buf;
     block_t *p_out_buffer;
 
-    if( !pp_block || !*pp_block ) return NULL;
-
-    block_t *p_block = *pp_block;
+    block_t *p_block = pp_block ? *pp_block : NULL;
 
+    if (p_block) {
         if( p_block->i_flags&(BLOCK_FLAG_DISCONTINUITY|BLOCK_FLAG_CORRUPTED) )
         {
             if( p_block->i_flags&BLOCK_FLAG_CORRUPTED )
@@ -216,6 +215,8 @@ static block_t *DecodeBlock( decoder_t *p_dec, block_t **pp_block )
         }
 
         block_BytestreamPush( &p_sys->bytestream, p_block );
+    } else
+        p_sys->i_state = STATE_SEND_DATA; /* return all the data we have left */
 
     while( 1 )
     {
@@ -470,7 +471,11 @@ static block_t *DecodeBlock( decoder_t *p_dec, block_t **pp_block )
                 p_sys->i_pts = p_sys->bytestream.p_block->i_pts = VLC_TS_INVALID;
 
             /* So p_block doesn't get re-added several times */
-            *pp_block = block_BytestreamPop( &p_sys->bytestream );
+            p_block = block_BytestreamPop( &p_sys->bytestream );
+            if (pp_block)
+                *pp_block = p_block;
+            else if (p_block)
+                block_Release(p_block);
 
             return p_out_buffer;
         }