midi: accomodated MIDI event running status

wader · Aug 17, 2024 · b2e71a3 · b2e71a3
1 parent 0226fc6
commit b2e71a3
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Showing 3 changed files with 72 additions and 61 deletions.
diff --git a/format/midi/TODO.md b/format/midi/TODO.md
@@ -35,8 +35,9 @@
     - [x] key signature
           - [ ] check key mappings
     - [x] time signature
-    - [ ] sequencer specific event
+    - [x] sequencer specific event
           - [ ] map manufacturer
+    - [ ] Use FieldUTF8String
 
 - midi events
     - [x] note off
@@ -48,7 +49,7 @@
     - [x] program change
     - [x] channel pressure
     - [x] pitch bend
-    - [ ] running status
+    - [x] running status
 
 - sysex events
     - [ ] message

diff --git a/format/midi/midi.go b/format/midi/midi.go
@@ -90,14 +90,25 @@ func decodeMTrk(d *decode.D) {
 
 	d.FieldArray("events", func(d *decode.D) {
 		d.FramedFn(int64(length)*8, func(d *decode.D) {
+			var running uint8 = 0x000
+
 			for d.BitsLeft() > 0 {
-				decodeEvent(d)
+				_, status, _ := peekEvent(d)
+				if status < 0x80 {
+					status = running
+				} else if status == 0xff || status == 0xf0 || status == 0xf7 {
+					running = 0x00
+				} else {
+					running = status
+				}
+
+				decodeEvent(d, running)
 			}
 		})
 	})
 }
 
-func decodeEvent(d *decode.D) {
+func decodeEvent(d *decode.D, running uint8) {
 	_, status, event := peekEvent(d)
 
 	// ... meta event?
@@ -109,7 +120,11 @@ func decodeEvent(d *decode.D) {
 	// ... sysex event
 
 	// ... midi event?
-	decodeMIDIEvent(d, status)
+	if status < 0x80 {
+		decodeMIDIEvent(d, running)
+	} else {
+		decodeMIDIEvent(d, status)
+	}
 }
 
 func peekEvent(d *decode.D) (uint64, uint8, uint8) {

diff --git a/format/midi/midievents.go b/format/midi/midievents.go
@@ -107,33 +107,77 @@ var controllers = scalar.UintMapSymStr{
 func decodeMIDIEvent(d *decode.D, status uint8) {
 	event := status & 0xf0
 
+	channel := func(d *decode.D) uint64 {
+		b := d.PeekBytes(1)
+		if b[0] >= 0x80 {
+			d.BytesLen(1)
+		}
+
+		return uint64(status & 0x0f)
+	}
+
 	switch MidiEventType(event) {
 	case TypeNoteOff:
-		d.FieldStruct("NoteOff", decodeNoteOff)
+		d.FieldStruct("NoteOff", func(d *decode.D) {
+			d.FieldUintFn("delta", vlq)
+			d.FieldUintFn("channel", channel)
+
+			decodeNoteOff(d)
+		})
 		return
 
 	case TypeNoteOn:
-		d.FieldStruct("NoteOn", decodeNoteOn)
+		d.FieldStruct("NoteOn", func(d *decode.D) {
+			d.FieldUintFn("delta", vlq)
+			d.FieldUintFn("channel", channel)
+
+			decodeNoteOn(d)
+		})
 		return
 
 	case TypePolyphonicPressure:
-		d.FieldStruct("PolyphonicPressure", decodePolyphonicPressure)
+		d.FieldStruct("PolyphonicPressure", func(d *decode.D) {
+			d.FieldUintFn("delta", vlq)
+			d.FieldUintFn("channel", channel)
+
+			decodePolyphonicPressure(d)
+		})
 		return
 
 	case TypeController:
-		d.FieldStruct("Controller", decodeController)
+		d.FieldStruct("Controller", func(d *decode.D) {
+			d.FieldUintFn("delta", vlq)
+			d.FieldUintFn("channel", channel)
+
+			decodeController(d)
+		})
 		return
 
 	case TypeProgramChange:
-		d.FieldStruct("ProgramChange", decodeProgramChange)
+		d.FieldStruct("ProgramChange", func(d *decode.D) {
+			d.FieldUintFn("delta", vlq)
+			d.FieldUintFn("channel", channel)
+
+			decodeProgramChange(d)
+		})
 		return
 
 	case TypeChannelPressure:
-		d.FieldStruct("ChannelPressure", decodeChannelPressure)
+		d.FieldStruct("ChannelPressure", func(d *decode.D) {
+			d.FieldUintFn("delta", vlq)
+			d.FieldUintFn("channel", channel)
+
+			decodeChannelPressure(d)
+		})
 		return
 
 	case TypePitchBend:
-		d.FieldStruct("PitchBend", decodePitchBend)
+		d.FieldStruct("PitchBend", func(d *decode.D) {
+			d.FieldUintFn("delta", vlq)
+			d.FieldUintFn("channel", channel)
+
+			decodePitchBend(d)
+		})
 		return
 	}
 
@@ -146,82 +190,33 @@ func decodeMIDIEvent(d *decode.D, status uint8) {
 }
 
 func decodeNoteOff(d *decode.D) {
-	d.FieldUintFn("delta", vlq)
-	d.FieldUintFn("channel", func(d *decode.D) uint64 {
-		b := d.BytesLen(1)
-
-		return uint64(b[0] & 0x0f)
-	})
-
 	d.FieldU8("note")
 	d.FieldU8("velocity")
 }
 
 func decodeNoteOn(d *decode.D) {
-	d.FieldUintFn("delta", vlq)
-	d.FieldUintFn("channel", func(d *decode.D) uint64 {
-		b := d.BytesLen(1)
-
-		return uint64(b[0] & 0x0f)
-	})
-
 	d.FieldU8("note")
 	d.FieldU8("velocity")
 }
 
 func decodePolyphonicPressure(d *decode.D) {
-	d.FieldUintFn("delta", vlq)
-	d.FieldUintFn("channel", func(d *decode.D) uint64 {
-		b := d.BytesLen(1)
-
-		return uint64(b[0] & 0x0f)
-	})
-
 	d.FieldU8("pressure")
 }
 
 func decodeController(d *decode.D) {
-	d.FieldUintFn("delta", vlq)
-	d.FieldUintFn("channel", func(d *decode.D) uint64 {
-		b := d.BytesLen(1)
-
-		return uint64(b[0] & 0x0f)
-	})
-
 	d.FieldU8("controller", controllers)
 	d.FieldU8("value")
 }
 
 func decodeProgramChange(d *decode.D) {
-	d.FieldUintFn("delta", vlq)
-	d.FieldUintFn("channel", func(d *decode.D) uint64 {
-		b := d.BytesLen(1)
-
-		return uint64(b[0] & 0x0f)
-	})
-
 	d.FieldU8("program")
 }
 
 func decodeChannelPressure(d *decode.D) {
-	d.FieldUintFn("delta", vlq)
-	d.FieldUintFn("channel", func(d *decode.D) uint64 {
-		b := d.BytesLen(1)
-
-		return uint64(b[0] & 0x0f)
-	})
-
 	d.FieldU8("pressure")
 }
 
 func decodePitchBend(d *decode.D) {
-	d.FieldUintFn("delta", vlq)
-	d.FieldUintFn("channel", func(d *decode.D) uint64 {
-		b := d.BytesLen(1)
-
-		return uint64(b[0] & 0x0f)
-	})
-
 	d.FieldUintFn("bend", func(d *decode.D) uint64 {
 		data := d.BytesLen(2)