Update app.py

app.py

@@ -103,7 +103,13 @@ def render_midi(input_midi, render_options):
     new_fn = fn1+'.mid'
 
     patches = [0] * 16
+    channels = [0, 1, 2, 3, 4, 5, 6, 7, 8, 10, 11, 12, 13, 14, 15]
 
+    score_patches = sorted(set([e[6] for e in output_score])
+
+    for channel, patch in enumerate(channels[:len(score_patches)]):
+        patches[patch] = score_patches[channel]
+        
     detailed_stats = TMIDIX.Tegridy_ms_SONG_to_MIDI_Converter(output_score,
                                                               output_signature = 'Advanced MIDI Renderer',
                                                               output_file_name = fn1,