midi: experimenting with struct metaevent data

wader · Aug 13, 2024 · 9dfcb96 · 9dfcb96
1 parent 8b236a1
commit 9dfcb96
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Showing 3 changed files with 22 additions and 20 deletions.
diff --git a/format/midi/TODO.md b/format/midi/TODO.md
@@ -2,7 +2,7 @@
 
 - [ ] add to probe group
 - [x] move delta into events
-- [ ] somehow map VLF fields
+- [ ] tests
 
 - formats
     - [ ] format 0

diff --git a/format/midi/metaevents.go b/format/midi/metaevents.go
@@ -31,7 +31,7 @@ func decodeTrackName(d *decode.D) {
 	d.FieldUintFn("delta", vlq)
 	d.FieldU8("status")
 	d.FieldU8("event")
-	d.FieldStrFn("Name", func(d *decode.D) string {
+	d.FieldStrFn("name", func(d *decode.D) string {
 		return string(vlf(d))
 	})
 }
@@ -58,27 +58,28 @@ func decodeTimeSignature(d *decode.D) {
 	d.FieldUintFn("delta", vlq)
 	d.FieldU8("status")
 	d.FieldU8("event")
+	d.FieldStruct("signature", func(d *decode.D) {
+		bytes := vlf(d)
 
-	bytes := vlf(d)
+		if len(bytes) > 0 {
+			d.FieldValueUint("numerator", uint64(bytes[0]))
+		}
 
-	if len(bytes) > 0 {
-		d.FieldValueUint("numerator", uint64(bytes[0]))
-	}
+		if len(bytes) > 1 {
+			denominator := uint16(1)
+			for i := uint8(0); i < bytes[1]; i++ {
+				denominator *= 2
+			}
 
-	if len(bytes) > 1 {
-		denominator := uint16(1)
-		for i := uint8(0); i < bytes[1]; i++ {
-			denominator *= 2
+			d.FieldValueUint("denominator", uint64(denominator))
 		}
 
-		d.FieldValueUint("denominator", uint64(denominator))
-	}
-
-	if len(bytes) > 2 {
-		d.FieldValueUint("ticksPerClick", uint64(bytes[2]))
-	}
+		if len(bytes) > 2 {
+			d.FieldValueUint("ticksPerClick", uint64(bytes[2]))
+		}
 
-	if len(bytes) > 3 {
-		d.FieldValueUint("thirtySecondsPerQuarter", uint64(bytes[3]))
-	}
+		if len(bytes) > 3 {
+			d.FieldValueUint("thirtySecondsPerQuarter", uint64(bytes[3]))
+		}
+	})
 }
diff --git a/format/midi/midi.go b/format/midi/midi.go
@@ -92,7 +92,8 @@ func decodeMTrk(d *decode.D) {
 	d.FieldArray("events", func(d *decode.D) {
 		d.FramedFn(int64(length)*8, func(d *decode.D) {
 			for d.BitsLeft() > 0 {
-				d.FieldStruct("event", decodeEvent)
+				// d.FieldStruct("event", decodeEvent)
+				decodeEvent(d)
 			}
 		})
 	})