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midi: reworked metaevent decoding for PR comments
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- fixed remaining snake-cased event names in tests and examples (cf. #1004 (comment))
- report 'status' and 'event' seperately (cf. #1004 (comment))
- decoded TimeSignature metaevent as length + byte fields (cf. #1004 (comment))
- decoded SequencerSpecificEvent metaevent as length + byte fields (cf. #1004 (comment))
- reworked Errorf's as Fatalf's for data reads (cf. #1004 (comment))
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@twystd
twystd committed Sep 1, 2024
1 parent 7950dd6 commit e940f47
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Showing 16 changed files with 409 additions and 295 deletions.
179 changes: 83 additions & 96 deletions format/midi/metaevents.go
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Original file line number Diff line number Diff line change
Expand Up @@ -7,48 +7,46 @@ import (
"github.com/wader/fq/pkg/scalar"
)

type MetaEventType uint8

const (
TypeSequenceNumber MetaEventType = 0x00
TypeText MetaEventType = 0x01
TypeCopyright MetaEventType = 0x02
TypeTrackName MetaEventType = 0x03
TypeInstrumentName MetaEventType = 0x04
TypeLyric MetaEventType = 0x05
TypeMarker MetaEventType = 0x06
TypeCuePoint MetaEventType = 0x07
TypeProgramName MetaEventType = 0x08
TypeDeviceName MetaEventType = 0x09
TypeMIDIChannelPrefix MetaEventType = 0x20
TypeMIDIPort MetaEventType = 0x21
TypeTempo MetaEventType = 0x51
TypeSMPTEOffset MetaEventType = 0x54
TypeTimeSignature MetaEventType = 0x58
TypeKeySignature MetaEventType = 0x59
TypeEndOfTrack MetaEventType = 0x2f
TypeSequencerSpecificEvent MetaEventType = 0x7f
TypeSequenceNumber uint64 = 0x00
TypeText uint64 = 0x01
TypeCopyright uint64 = 0x02
TypeTrackName uint64 = 0x03
TypeInstrumentName uint64 = 0x04
TypeLyric uint64 = 0x05
TypeMarker uint64 = 0x06
TypeCuePoint uint64 = 0x07
TypeProgramName uint64 = 0x08
TypeDeviceName uint64 = 0x09
TypeMIDIChannelPrefix uint64 = 0x20
TypeMIDIPort uint64 = 0x21
TypeTempo uint64 = 0x51
TypeSMPTEOffset uint64 = 0x54
TypeTimeSignature uint64 = 0x58
TypeKeySignature uint64 = 0x59
TypeEndOfTrack uint64 = 0x2f
TypeSequencerSpecificEvent uint64 = 0x7f
)

var metaevents = scalar.UintMapSymStr{
0xff00: "sequence_number",
0xff01: "text",
0xff02: "copyright",
0xff03: "track_name",
0xff04: "instrument_name",
0xff05: "lyric",
0xff06: "marker",
0xff07: "cue_point",
0xff08: "program_name",
0xff09: "device_name",
0xff20: "midi_channel_prefix",
0xff21: "midi_port",
0xff51: "tempo",
0xff54: "smpte_offset",
0xff58: "time_signature",
0xff59: "key_signature",
0xff2f: "end_of_track",
0xff7f: "sequencer_specific_event",
TypeSequenceNumber: "sequence_number",
TypeText: "text",
TypeCopyright: "copyright",
TypeTrackName: "track_name",
TypeInstrumentName: "instrument_name",
TypeLyric: "lyric",
TypeMarker: "marker",
TypeCuePoint: "cue_point",
TypeProgramName: "program_name",
TypeDeviceName: "device_name",
TypeMIDIChannelPrefix: "midi_channel_prefix",
TypeMIDIPort: "midi_port",
TypeTempo: "tempo",
TypeSMPTEOffset: "smpte_offset",
TypeTimeSignature: "time_signature",
TypeKeySignature: "key_signature",
TypeEndOfTrack: "end_of_track",
TypeSequencerSpecificEvent: "sequencer_specific_event",
}

var framerates = scalar.UintMapSymUint{
Expand All @@ -72,12 +70,13 @@ func decodeMetaEvent(d *decode.D, event uint8, ctx *context) {
metaevent := func(name string, f func(d *decode.D)) {
d.FieldStruct(name, func(d *decode.D) {
d.FieldStruct("time", delta)
d.FieldU16("event", metaevents)
d.FieldU8("status")
d.FieldU8("event", metaevents)
f(d)
})
}

switch MetaEventType(event) {
switch uint64(event) {
case TypeSequenceNumber:
metaevent("sequence_number", decodeSequenceNumber)

Expand Down Expand Up @@ -142,7 +141,7 @@ func decodeSequenceNumber(d *decode.D) {
seqno := uint64(0)

if data, err := vlf(d); err != nil {
d.Errorf("%v", err)
d.Fatalf("%v", err)
} else {
if len(data) > 0 {
seqno += uint64(data[0])
Expand Down Expand Up @@ -199,7 +198,7 @@ func decodeMIDIChannelPrefix(d *decode.D) {
channel := uint64(0)

if data, err := vlf(d); err != nil {
d.Errorf("%v", err)
d.Fatalf("%v", err)
} else {
for _, b := range data {
channel <<= 8
Expand All @@ -216,7 +215,7 @@ func decodeMIDIPort(d *decode.D) {
port := uint64(0)

if data, err := vlf(d); err != nil {
d.Errorf("%v", err)
d.Fatalf("%v", err)
} else {
for _, b := range data {
port <<= 8
Expand All @@ -233,7 +232,7 @@ func decodeTempo(d *decode.D) {
tempo := uint64(0)

if data, err := vlf(d); err != nil {
d.Errorf("%v", err)
d.Fatalf("%v", err)
} else {
for _, b := range data {
tempo <<= 8
Expand All @@ -252,7 +251,7 @@ func decodeSMPTEOffset(d *decode.D) {

d.FieldStrFn("bytes", func(d *decode.D) string {
if data, err = vlf(d); err != nil {
d.Errorf("%v", err)
d.Fatalf("%v", err)
} else {
return fmt.Sprintf("%v", data)
}
Expand Down Expand Up @@ -288,38 +287,29 @@ func decodeSMPTEOffset(d *decode.D) {

func decodeTimeSignature(d *decode.D) {
d.FieldStruct("signature", func(d *decode.D) {
var data []uint8
var err error

d.FieldStrFn("bytes", func(d *decode.D) string {
if data, err = vlf(d); err != nil {
d.Errorf("%v", err)
} else {
return fmt.Sprintf("%v", data)
}
length := d.FieldUintFn("length", vlq)

return "[]"
})

if len(data) > 0 {
d.FieldValueUint("numerator", uint64(data[0]))
if length > 0 {
d.FieldU8("numerator")
}

if len(data) > 1 {
denominator := uint64(1)
for i := uint8(0); i < data[1]; i++ {
denominator <<= 1
}

d.FieldValueUint("denominator", denominator)
if length > 1 {
d.FieldUintFn("denominator", func(d *decode.D) uint64 {
denominator := uint64(1)
v := d.U8()
for i := uint64(0); i < v; i++ {
denominator <<= 1
}
return denominator
})
}

if len(data) > 2 {
d.FieldValueUint("ticks_per_click", uint64(data[2]))
if length > 2 {
d.FieldU8("ticks_per_click")
}

if len(data) > 3 {
d.FieldValueUint("thirty_seconds_per_quarter", uint64(data[3]))
if length > 3 {
d.FieldU8("thirty_seconds_per_quarter")
}
})
}
Expand All @@ -329,7 +319,7 @@ func decodeKeySignature(d *decode.D) {
key := uint64(0)

if data, err := vlf(d); err != nil {
d.Errorf("%v", err)
d.Fatalf("%v", err)
} else {
if len(data) > 0 {
key <<= 8
Expand All @@ -352,7 +342,7 @@ func decodeEndOfTrack(d *decode.D) {
length := 0

if data, err := vlf(d); err != nil {
d.Errorf("%v", err)
d.Fatalf("%v", err)
} else {
length = len(data)
}
Expand All @@ -363,30 +353,27 @@ func decodeEndOfTrack(d *decode.D) {

func decodeSequencerSpecificEvent(d *decode.D) {
d.FieldStruct("info", func(d *decode.D) {
var data []uint8
var err error

d.FieldStrFn("bytes", func(d *decode.D) string {
if data, err = vlf(d); err != nil {
d.Errorf("%v", err)
} else {
return fmt.Sprintf("%v", data)
}

return "[]"
})

if len(data) > 2 && data[0] == 0x00 {
d.FieldValueStr("manufacturer", fmt.Sprintf("%02X%02X", data[1], data[2]), manufacturers)

if len(data) > 3 {
d.FieldValueStr("data", fmt.Sprintf("%v", data[3:]))
}

} else if len(data) > 0 {
d.FieldValueStr("manufacturer", fmt.Sprintf("%02x", data[0]), manufacturers)
if len(data) > 1 {
d.FieldValueStr("data", fmt.Sprintf("%v", data[1:]))
if length := d.FieldUintFn("length", vlq); length > 0 {
b := d.PeekUintBits(8)

if length > 2 && b == 0 {
d.FieldStrFn("manufacturer", func(d *decode.D) string {
manufacturer := d.BytesLen(3)

return fmt.Sprintf("%02X%02X", manufacturer[1], manufacturer[2])
}, manufacturers)

if length > 3 {
d.FieldRawLen("data", 8*(int64(length)-3))
}
} else if length > 0 {
d.FieldStrFn("manufacturer", func(d *decode.D) string {
return fmt.Sprintf("%02X", d.U8())
}, manufacturers)

if length > 1 {
d.FieldRawLen("data", 8*(int64(length)-1))
}
}
}
})
Expand Down
2 changes: 1 addition & 1 deletion format/midi/midi.go
View file
Original file line number Diff line number Diff line change
Expand Up @@ -195,7 +195,7 @@ func vlf(d *decode.D) ([]uint8, error) {
// Variable length string with a big endian varint length
func vlstring(d *decode.D) string {
if data, err := vlf(d); err != nil {
d.Errorf("%v", err)
d.Fatalf("%v", err)
} else {
return string(data)
}
Expand Down
6 changes: 3 additions & 3 deletions format/midi/midi.md
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Original file line number Diff line number Diff line change
Expand Up @@ -7,7 +7,7 @@

1. Extract the track names from a MIDI file
```
fq -d midi -d midi '.. | select(.event=="track name")? | "\(.name)"' twinkle.mid
fq -d midi -d midi '.. | select(.event=="track_name")? | "\(.name)"' twinkle.mid
```

2. Extract the tempo changes from a MIDI file
Expand All @@ -17,12 +17,12 @@ fq -d midi '.. | select(.event=="tempo")?.tempo' twinkle.mid

3. Extract the key changes from a MIDI file
```
fq -d midi '.. | select(.event=="key signature")?.key' key-signatures.mid
fq -d midi '.. | select(.event=="key_signature")?.key' key-signatures.mid
```

4. Extract NoteOn and NoteOff events:
```
fq -d midi 'grep_by(.event=="note on" or .event=="note off") | "\(.event) \(.time.tick) \(.note)"' twinkle.mid
fq -d midi 'grep_by(.event=="note_on" or .event=="note_off") | "\(.event) \(.time.tick) \(.note)"' twinkle.mid
```

### Authors
Expand Down
6 changes: 3 additions & 3 deletions format/midi/sysex.go
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Original file line number Diff line number Diff line change
Expand Up @@ -71,7 +71,7 @@ func decodeSysExMessage(d *decode.D, ctx *context) {

d.FieldStrFn("bytes", func(d *decode.D) string {
if bytes, err = vlf(d); err != nil {
d.Errorf("%v", err)
d.Fatalf("%v", err)
} else {
return fmt.Sprintf("%v", bytes)
}
Expand Down Expand Up @@ -113,7 +113,7 @@ func decodeSysExContinuation(d *decode.D, ctx *context) {

d.FieldStrFn("bytes", func(d *decode.D) string {
if data, err = vlf(d); err != nil {
d.Errorf("%v", err)
d.Fatalf("%v", err)
} else {
return fmt.Sprintf("%v", data)
}
Expand Down Expand Up @@ -142,7 +142,7 @@ func decodeSysExEscape(d *decode.D, ctx *context) {

d.FieldStrFn("bytes", func(d *decode.D) string {
if data, err = vlf(d); err != nil {
d.Errorf("%v", err)
d.Fatalf("%v", err)
} else {
return fmt.Sprintf("%v", data)
}
Expand Down
3 changes: 2 additions & 1 deletion format/midi/testdata/Makefile
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Original file line number Diff line number Diff line change
Expand Up @@ -15,7 +15,8 @@ run: build
debug: build
# go run . -d midi dv format/midi/workdir/15ba2fe0cd4bf33a.mid
# go run . -d midi dv format/midi/testdata/unknown-chunks.mid
go test ./format -run TestFormats/all/all.fqtest
# go test ./format -run TestFormats/all/all.fqtest
go run . -d midi dv format/midi/workdir/sequencer-specific-event.mid

test: build
go test ./format -run TestFormats/midi
Expand Down
1 change: 0 additions & 1 deletion format/midi/testdata/README.md
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Original file line number Diff line number Diff line change
Expand Up @@ -30,7 +30,6 @@ Test file with all supported MIDI key signatures.

Test file with all supported MIDI notes.


8. _twinkle.mid_

Sample MIDI file for the example queries in the help.
Expand Down
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