remove empty midi tracks when importing a midi file (~alextee/zrythm-bug#141)

inc/audio/midi_file.h

@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2020 Alexandros Theodotou <alex at zrythm dot org>
+ * Copyright (C) 2020-2021 Alexandros Theodotou <alex at zrythm dot org>
  *
  * This file is part of Zrythm
  *
@@ -26,6 +26,8 @@
 #ifndef __AUDIO_MIDI_FILE_H__
 #define __AUDIO_MIDI_FILE_H__
 
+#include "ext/midilib/src/midifile.h"
+
 #include <stdbool.h>
 
 /**
@@ -34,6 +36,15 @@
  * @{
  */
 
+/**
+ * Returns whether the given track in the midi file
+ * has data.
+ */
+bool
+midi_file_track_has_data (
+  const char * abs_path,
+  int          track_idx);
+
 /**
  * Returns the number of tracks in the MIDI file.
  */

src/audio/midi_file.c

@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2020 Alexandros Theodotou <alex at zrythm dot org>
+ * Copyright (C) 2020-2021 Alexandros Theodotou <alex at zrythm dot org>
  *
  * This file is part of Zrythm
  *
@@ -23,6 +23,65 @@
 
 #include <gtk/gtk.h>
 
+/**
+ * Returns whether the given track in the midi file
+ * has data.
+ */
+bool
+midi_file_track_has_data (
+  const char * abs_path,
+  int          track_idx)
+{
+  MIDI_FILE * mf = midiFileOpen (abs_path);
+  g_return_val_if_fail (mf, false);
+
+  MIDI_MSG msg;
+  midiReadInitMessage (&msg);
+
+  int ev;
+  g_debug ("reading MIDI Track %d", track_idx);
+  bool have_data = false;
+  while (midiReadGetNextMessage (
+           mf, track_idx, &msg))
+    {
+      if (msg.bImpliedMsg)
+        {
+          ev = msg.iImpliedMsg;
+        }
+      else
+        {
+          ev = msg.iType;
+        }
+
+      switch(ev)
+        {
+        case msgNoteOff:
+        case msgMetaEvent:
+          break;
+        case msgNoteOn:
+        case msgNoteKeyPressure:
+        case msgSetParameter:
+        case msgSetProgram:
+        case msgChangePressure:
+        case msgSetPitchWheel:
+        case msgSysEx1:
+        case msgSysEx2:
+          have_data = true;
+          break;
+        }
+
+      if (have_data)
+        {
+          break;
+        }
+    }
+
+  midiReadFreeMessage (&msg);
+  midiFileClose (mf);
+
+  return have_data;
+}
+
 /**
  * Returns the number of tracks in the MIDI file.
  */
@@ -35,9 +94,26 @@ midi_file_get_num_tracks (
     midiFileOpen (abs_path);
   g_return_val_if_fail (mf, -1);
 
+  int actual_num = 0;
+
   int num = midiReadGetNumTracks (mf);
   g_debug ("%s: num tracks = %d", abs_path, num);
+
+  if (!non_empty_only)
+  {
+    midiFileClose (mf);
+    return num;
+  }
+
+  for (int i = 0; i < num; i++)
+    {
+      if (midi_file_track_has_data (abs_path, i))
+        {
+          actual_num++;
+        }
+    }
+
   midiFileClose (mf);
 
-  return num;
+  return actual_num;
 }

src/audio/midi_region.c

@@ -40,6 +40,7 @@
 #include "audio/channel.h"
 #include "audio/exporter.h"
 #include "audio/midi_event.h"
+#include "audio/midi_file.h"
 #include "audio/midi_note.h"
 #include "audio/midi_region.h"
 #include "audio/region.h"
@@ -413,9 +414,9 @@ midi_region_new_from_midi_file (
   g_return_val_if_fail (mf, NULL);
 
   char str[128];
+  char txt[60000];
   int ev;
   MIDI_MSG msg;
-  int i, iNum;
   unsigned int j;
   Position pos, global_pos;
   MidiNote * mn;
@@ -429,19 +430,30 @@ midi_region_new_from_midi_file (
     lane_pos, idx_inside_lane);
 
   midiReadInitMessage (&msg);
-  iNum = midiReadGetNumTracks(mf);
+  int num_tracks = midiReadGetNumTracks (mf);
   double ppqn = (double) midiFileGetPPQN (mf);
   double transport_ppqn =
     transport_get_ppqn (TRANSPORT);
 
-  for(i = 0; i < iNum; i++)
+  int actual_iter = 0;
+
+  for (int i = 0; i < num_tracks; i++)
     {
-      if (i != idx)
-        continue;
+      if (!midi_file_track_has_data (abs_path, i))
+        {
+          continue;
+        }
+
+      if (actual_iter != idx)
+        {
+          actual_iter++;
+          continue;
+        }
 
       g_message (
         "%s: reading MIDI Track %d", __func__, i);
-      while(midiReadGetNextMessage (mf, i, &msg))
+      g_return_val_if_fail (i < 1000, NULL);
+      while (midiReadGetNextMessage (mf, i, &msg))
         {
           /* convert time to zrythm time */
           ticks =
@@ -715,7 +727,6 @@ handle_note_off:
             }
           else
             {
-              char txt[600];
               char tmp[100];
               strcpy (txt, "[");
               if (msg.bImpliedMsg)
@@ -734,6 +745,11 @@ handle_note_off:
               g_debug ("%s", txt);
             }
         }
+
+      if (actual_iter == idx)
+        {
+          break;
+        }
     }
 
   midiReadFreeMessage (&msg);
@@ -763,7 +779,9 @@ handle_note_off:
     position_is_before (
       &self->base.pos, &self->base.end_pos), NULL);
 
-  g_message ("%s: done", __func__);
+  g_message (
+    "%s: done ~ %d MIDI notes read", __func__,
+    self->num_midi_notes);
 
   return self;
 }

tests/actions/tracklist_selections.c

@@ -80,16 +80,13 @@ test_create_from_midi_file (void)
 
   char * midi_file;
 
-  /* TODO this should pass in the future */
-#if 0
   midi_file =
     g_build_filename (
       TESTS_SRCDIR,
       "1_empty_track_1_track_with_data.mid",
       NULL);
-  test_num_tracks_with_file (midi_file, 2);
+  test_num_tracks_with_file (midi_file, 1);
   g_free (midi_file);
-#endif
 
   midi_file =
     g_build_filename (
@@ -103,6 +100,13 @@ test_create_from_midi_file (void)
     TRACKLIST->tracks[TRACKLIST->num_tracks - 1]->
       lanes[0]->regions[0]->num_midi_notes, ==, 3);
 
+  midi_file =
+    g_build_filename (
+      TESTS_SRCDIR, "those_who_remain.mid",
+      NULL);
+  test_num_tracks_with_file (midi_file, 1);
+  g_free (midi_file);
+
   test_helper_zrythm_cleanup ();
 }