decoder: simplify audio path

DecoderPlayAudio() has no effects with a NULL block.

src/input/decoder.c

@@ -1073,7 +1073,7 @@ static void DecoderPlayAudio( decoder_t *p_dec, block_t *p_audio,
     audio_output_t *p_aout = p_owner->p_aout;
 
     /* */
-    if( p_audio && p_audio->i_pts <= VLC_TS_INVALID ) // FIXME --VLC_TS_INVALID verify audio_output/*
+    if( p_audio->i_pts <= VLC_TS_INVALID ) // FIXME --VLC_TS_INVALID verify audio_output/*
     {
         msg_Warn( p_dec, "non-dated audio buffer received" );
         *pi_lost_sum += 1;
@@ -1083,23 +1083,15 @@ static void DecoderPlayAudio( decoder_t *p_dec, block_t *p_audio,
 
     /* */
     vlc_mutex_lock( &p_owner->lock );
-
-    if( p_audio && p_owner->b_waiting )
+race:
+    if( p_owner->b_waiting )
     {
         p_owner->b_has_data = true;
         vlc_cond_signal( &p_owner->wait_acknowledge );
     }
 
-    for( ;; )
-    {
-        bool b_paused;
-
     bool b_reject = DecoderWaitUnblock( p_dec );
-
-        b_paused = p_owner->b_paused;
-
-        if (!p_audio)
-            break;
+    bool b_paused = p_owner->b_paused;
 
     /* */
     int i_rate = INPUT_RATE_DEFAULT;
@@ -1116,7 +1108,7 @@ static void DecoderPlayAudio( decoder_t *p_dec, block_t *p_audio,
                      p_audio->i_pts - AOUT_MAX_PREPARE_TIME );
 
     if( unlikely(p_owner->b_paused != b_paused) )
-            continue; /* race with input thread? retry... */
+        goto race; /* race with input thread? retry... */
     if( p_aout == NULL )
         b_reject = true;
 
@@ -1133,9 +1125,6 @@ static void DecoderPlayAudio( decoder_t *p_dec, block_t *p_audio,
         *pi_lost_sum += 1;
         block_Release( p_audio );
     }
-
-        break;
-    }
     vlc_mutex_unlock( &p_owner->lock );
 }
 
@@ -1147,11 +1136,10 @@ static void DecoderDecodeAudio( decoder_t *p_dec, block_t *p_block )
     int i_lost = 0;
     int i_played = 0;
 
-    if (!p_block) {
-        /* Play a NULL block to output buffered frames */
-        DecoderPlayAudio( p_dec, NULL, &i_played, &i_lost );
-    }
-    else while( (p_aout_buf = p_dec->pf_decode_audio( p_dec, &p_block )) )
+    if( p_block == NULL )
+        return; /* TODO: remove this check, drain audio decoders properly */
+
+    while( (p_aout_buf = p_dec->pf_decode_audio( p_dec, &p_block )) )
     {
         if( DecoderIsFlushing( p_dec ) )
         {