mvp: fall back to stereo

When the channel count is greater than 2, fall back to stereo sound.

NEWS

@@ -17,6 +17,7 @@ ver 0.15 - (200?/??/??)
 * audio outputs:
   - shout: enlarged buffer size to 32 kB
   - null: allow disabling synchronization
+  - mvp: fall back to stereo
 * commands:
   - "playlistinfo" supports a range now
   - added "sticker database", command "sticker", which allows clients

src/output/mvp_plugin.c

@@ -134,7 +134,11 @@ mvp_set_pcm_params(struct mvp_data *md, struct audio_format *audio_format)
 		break;
 
 	default:
-		return false;
+		g_debug("unsupported channel count %u - falling back to stereo",
+			audio_format->channels);
+		audio_format->channels = 2;
+		mix[0] = 0;
+		break;
 	}
 
 	/* 0,1=24bit(24) , 2,3=16bit */