/
segment.go
345 lines (292 loc) · 8.06 KB
/
segment.go
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package gaudio
import (
"bytes"
"crypto/md5"
"encoding/binary"
"errors"
"fmt"
"io"
"os"
"github.com/gotracker/gomixing/mixing"
"github.com/gotracker/gomixing/sampling"
tformat "github.com/gotracker/playback/format"
"github.com/gotracker/playback/output"
"github.com/gotracker/playback/player/feature"
"github.com/gotracker/playback/song"
"github.com/hajimehoshi/go-mp3"
"github.com/mewkiz/flac"
"github.com/mjibson/go-dsp/wav"
"github.com/zeozeozeo/gomodplay/pkg/mod"
)
type Segment struct {
Data []float32
Channels int // Amount of channels (will be 2, even if there is one)
SampleRate uint64 // The sample rate of the segment
Length uint64 // Length of the segment in samples
LengthSeconds float64 // Length of the segment in seconds
Format AudioFormat
}
var (
errInvalidChecksum error = errors.New("invalid checksum")
)
// Loads an audio file from a reader.
func LoadAudio(reader io.Reader, format AudioFormat) (*Segment, error) {
segment := &Segment{}
switch format {
case FormatMP3:
err := decodeMp3(segment, reader)
if err != nil {
return nil, err
}
case FormatWAVE:
err := decodeWav(segment, reader)
if err != nil {
return nil, err
}
case FormatFLAC:
err := decodeFlac(segment, reader)
if err != nil {
return nil, err
}
case FormatMOD:
err := decodeMod(segment, reader)
if err != nil {
return nil, err
}
case FormatGotrackerMod, FormatS3M, FormatXM, FormatIT:
err := decodeTrackerModule(segment, reader, format)
if err != nil {
return nil, err
}
}
// segment.Normalize()
return segment, nil
}
// Loads an audio file from the file path.
func LoadAudioFromPath(path string, format AudioFormat) (*Segment, error) {
file, err := os.Open(path)
if err != nil {
return nil, err
}
defer file.Close()
return LoadAudio(file, format)
}
// Converts a float32 array to a Segment.
// Structure of the audio array values (assume you have 2 channels):
// [channel 1 val, channel 2 val, channel 1 val, channel 2 val, ...]
func SegmentFromData(data []float32, channels int, sampleRate uint64) *Segment {
if channels < 1 {
channels = 1
}
if sampleRate < 1 {
sampleRate = 1
}
segmentLength := uint64(len(data)) / uint64(channels)
segment := &Segment{
Data: data,
Channels: channels,
SampleRate: sampleRate,
Length: segmentLength,
LengthSeconds: float64(segmentLength) / float64(sampleRate),
Format: FormatRAW,
}
// segment.Normalize()
return segment
}
// Returns a silent segment, with the length of n seconds.
func Silent(seconds float64, sampleRate uint64, channels uint) *Segment {
if sampleRate < 1 {
sampleRate = 1
}
if seconds < 0 {
seconds = 0
}
dataLength := uint64(seconds*float64(sampleRate)) * uint64(channels)
return &Segment{
Data: make([]float32, dataLength),
Channels: int(channels),
SampleRate: sampleRate,
Length: dataLength / uint64(channels),
LengthSeconds: (float64(dataLength) / float64(channels)) / float64(sampleRate),
Format: FormatRAW,
}
}
// Returns an empty segment.
func Empty(sampleRate uint64, channels uint) *Segment {
return &Segment{
Channels: int(channels),
SampleRate: sampleRate,
Length: 0,
LengthSeconds: 0,
Format: FormatRAW,
}
}
func convertBytesToFloat32(data []byte, dataLength uint64) []float32 {
resultLength := dataLength / uint64(2)
result := make([]float32, resultLength)
for i := uint64(0); i < resultLength; i++ {
s16 := int16(binary.LittleEndian.Uint16(data[2*i : 2*i+2]))
float := float32(s16) / 0x7FFF
result[i] = float
}
return result
}
func decodeMp3(segment *Segment, reader io.Reader) error {
decoder, err := mp3.NewDecoder(reader)
if err != nil {
return err
}
segment.SampleRate = uint64(decoder.SampleRate())
buf := new(bytes.Buffer)
_, err = buf.ReadFrom(decoder)
if err != nil {
return err
}
dataLength := uint64(decoder.Length())
segment.Data = convertBytesToFloat32(buf.Bytes(), dataLength)
segment.Channels = 2 // go-mp3 always outputs 2 channels
segment.Length = dataLength / 4
segment.LengthSeconds = float64(segment.Length) / float64(segment.SampleRate)
segment.Format = FormatMP3
return nil
}
func decodeWav(segment *Segment, reader io.Reader) error {
decoder, err := wav.New(reader)
if err != nil {
return err
}
segment.Data, err = decoder.ReadFloats(decoder.Samples)
if err != nil {
fmt.Printf("died %s", err)
return err
}
segment.SampleRate = uint64(decoder.SampleRate)
segment.Channels = int(decoder.NumChannels)
segment.Length = uint64(decoder.Samples / segment.Channels)
segment.LengthSeconds = float64(segment.Length) / float64(segment.SampleRate)
segment.Format = FormatWAVE
return nil
}
func decodeFlac(segment *Segment, reader io.Reader) error {
stream, err := flac.New(reader)
if err != nil {
return err
}
segment.Channels = int(stream.Info.NChannels)
segment.SampleRate = uint64(stream.Info.SampleRate)
segment.Length = stream.Info.NSamples
segment.LengthSeconds = float64(segment.Length) / float64(segment.SampleRate)
segment.Format = FormatFLAC
// TODO: Find a better way to do this
dataLength := segment.Length * uint64(segment.Channels)
channelsData := make([][]float32, segment.Channels)
segment.Data = make([]float32, dataLength)
md5sum := md5.New()
for {
frame, err := stream.ParseNext()
if err != nil {
if err == io.EOF {
break
}
return err
}
frame.Hash(md5sum)
// Iterate through all channels (subframes)
for channelNum, subframe := range frame.Subframes {
for _, sample := range subframe.Samples {
channelsData[channelNum] = append(channelsData[channelNum], float32(sample)/0x7FFF)
}
}
}
gotSum, wantSum := md5sum.Sum(nil), stream.Info.MD5sum[:]
if !bytes.Equal(gotSum, wantSum) {
return errInvalidChecksum
}
for i := uint64(0); i < dataLength; i++ {
segment.Data[i] = channelsData[i%uint64(segment.Channels)][i/uint64(segment.Channels)]
}
return nil
}
func decodeMod(segment *Segment, reader io.Reader) error {
sampleRate := 44100
player := mod.NewModPlayer(uint32(sampleRate))
err := player.LoadModFile(reader)
if err != nil {
return err
}
segment.Channels = 2
segment.SampleRate = uint64(sampleRate)
segment.Format = FormatMOD
player.Play()
for {
samples := make([][2]float32, 1)
_, ok := player.Stream(samples)
if !ok || player.State.HasLooped {
break
}
segment.Data = append(segment.Data, samples[0][0], samples[0][1])
segment.Length++
}
segment.LengthSeconds = float64(segment.Length) / float64(sampleRate)
segment.Normalize()
return nil
}
// Decodes .xm, .it, .s3m, .mod modules (with Gotracker)
func decodeTrackerModule(segment *Segment, reader io.Reader, format AudioFormat) error {
var features []feature.Feature
features = append(features,
feature.UseNativeSampleFormat(true),
feature.IgnoreUnknownEffect{Enabled: true},
feature.SongLoop{Count: 0},
)
// Make a readseeker
buf := new(bytes.Buffer)
buf.ReadFrom(reader)
readseeker := FakeReadSeeker(buf.Bytes())
// Setup player
player, _, err := tformat.LoadFromReader(GetFormatString(format), &readseeker, features...)
if err != nil {
return err
}
if err := player.SetupSampler(44100, 2); err != nil {
return err
}
if err := player.Configure(features); err != nil {
return err
}
premixDataChannel := make(chan *output.PremixData, 8)
defer close(premixDataChannel)
// Create mixers
mixer := mixing.Mixer{
Channels: 2,
}
panMixer := mixing.GetPanMixer(2)
go func() {
// Wait for data to appear
for premix := range premixDataChannel {
data := mixer.Flatten(
panMixer,
premix.SamplesLen,
premix.Data,
premix.MixerVolume,
sampling.Format16BitLESigned,
)
// Convert the data to float32 and append it to the segment
segment.Data = append(segment.Data, convertBytesToFloat32(data, uint64(len(data)))...)
}
}()
// Render the song
for {
if err := player.Update(0, premixDataChannel); err != nil {
if errors.Is(err, song.ErrStopSong) {
break
}
return err
}
}
segment.Channels = 2
segment.Format = format
segment.SampleRate = 44100
segment.UpdateLength()
return nil
}