Audio decoder: output buffered decoded frames on EOF

If EOF happens during buffering, the buffered frames will be flushed
and never played back.
This should only be visible for very short files such as:
http://streams.videolan.org/issues/9195/73ms-VLC-KO.wav

Note, pulse will lose the audio for such short files, alsa and afile work better

Closes: #3152

src/input/decoder.c

@@ -422,6 +422,9 @@ bool input_DecoderIsEmpty( decoder_t * p_dec )
     assert( !p_owner->b_buffering );
 
     bool b_empty = block_FifoCount( p_dec->p_owner->p_fifo ) <= 0;
+    if (p_owner->buffer.i_count) /* buffered frames */
+        b_empty = false;
+
     if( b_empty )
     {
         vlc_mutex_lock( &p_owner->lock );
@@ -923,7 +926,10 @@ static void *DecoderThread( void *p_data )
 
         /* Make sure there is no cancellation point other than this one^^.
          * If you need one, be sure to push cleanup of p_block. */
-        DecoderSignalBuffering( p_dec, p_block == NULL );
+        bool end_buffering = !p_block || p_block->i_flags & BLOCK_FLAG_CORE_EOS;
+        DecoderSignalBuffering( p_dec, end_buffering );
+        if (end_buffering)
+            input_DecoderStopBuffering( p_dec );
 
         if( p_block )
         {
@@ -1164,7 +1170,7 @@ static void DecoderPlayAudio( decoder_t *p_dec, block_t *p_audio,
     audio_output_t *p_aout = p_owner->p_aout;
 
     /* */
-    if( p_audio->i_pts <= VLC_TS_INVALID ) // FIXME --VLC_TS_INVALID verify audio_output/*
+    if( p_audio && 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;
@@ -1175,7 +1181,7 @@ static void DecoderPlayAudio( decoder_t *p_dec, block_t *p_audio,
     /* */
     vlc_mutex_lock( &p_owner->lock );
 
-    if( p_owner->b_buffering || p_owner->buffer.p_audio )
+    if( p_audio && (p_owner->b_buffering || p_owner->buffer.p_audio) )
     {
         p_audio->p_next = NULL;
 
@@ -1214,6 +1220,9 @@ static void DecoderPlayAudio( decoder_t *p_dec, block_t *p_audio,
                 p_owner->buffer.pp_audio_next = &p_owner->buffer.p_audio;
         }
 
+        if (!p_audio)
+            break;
+
         /* */
         int i_rate = INPUT_RATE_DEFAULT;
 
@@ -1263,7 +1272,11 @@ static void DecoderDecodeAudio( decoder_t *p_dec, block_t *p_block )
     int i_lost = 0;
     int i_played = 0;
 
-    while( (p_aout_buf = p_dec->pf_decode_audio( p_dec, &p_block )) )
+    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( DecoderIsExitRequested( p_dec ) )
         {
@@ -1889,7 +1902,7 @@ static void DecoderProcessAudio( decoder_t *p_dec, block_t *p_block, bool b_flus
                 DecoderDecodeAudio( p_dec, p_null );
         }
     }
-    else if( p_block )
+    else
     {
         DecoderDecodeAudio( p_dec, p_block );
     }