127 lines
2.7 KiB
Go
127 lines
2.7 KiB
Go
package go_alac
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import (
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"github.com/edgeware/mp4ff/bits"
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"github.com/edgeware/mp4ff/mp4"
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"io"
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"time"
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)
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type FormatEncoder struct {
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encoder *FrameEncoder
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writer io.Writer
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buffer []byte
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segmentDuration int64
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trackId uint32
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seqNumber uint32
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}
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type alacBox struct {
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cookie []byte
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}
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func (b *alacBox) Type() string {
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return "alac"
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}
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// Size - calculated size of box
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func (b *alacBox) Size() uint64 {
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return uint64(12 + len(b.cookie))
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}
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// Encode - write box to w
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func (b *alacBox) Encode(w io.Writer) error {
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sw := bits.NewFixedSliceWriter(int(b.Size()))
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err := b.EncodeSW(sw)
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if err != nil {
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return err
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}
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_, err = w.Write(sw.Bytes())
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return err
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}
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func (b *alacBox) EncodeSW(sw bits.SliceWriter) error {
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err := mp4.EncodeHeaderSW(b, sw)
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if err != nil {
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return err
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}
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sw.WriteUint32(0) //version
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sw.WriteBytes(b.cookie)
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return sw.AccError()
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}
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func (b *alacBox) Info(w io.Writer, specificBoxLevels, indent, indentStep string) error {
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return nil
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}
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func NewFormatEncoder(writer io.Writer, sampleRate, channels, bitDepth int, fastMode bool, segmentDuration time.Duration) *FormatEncoder {
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e := &FormatEncoder{
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encoder: NewFrameEncoder(sampleRate, channels, bitDepth, fastMode),
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writer: writer,
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segmentDuration: segmentDuration.Milliseconds(),
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}
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if e.encoder == nil {
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return nil
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}
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init := mp4.CreateEmptyInit()
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init.AddEmptyTrack(uint32(sampleRate), "audio", "en")
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e.trackId = init.Moov.Mvhd.NextTrackID - 1
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trak := init.Moov.Trak
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stsd := trak.Mdia.Minf.Stbl.Stsd
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//TODO: this does not work with 96kHz freq etc.
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mp4a := mp4.CreateAudioSampleEntryBox("alac", uint16(channels), uint16(bitDepth), uint16(sampleRate), &alacBox{
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cookie: e.encoder.GetMagicCookie(),
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})
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stsd.AddChild(mp4a)
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init.Encode(writer)
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return e
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}
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func (e *FormatEncoder) outputPacket(packet []byte) {
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//TODO: more frames
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seg := mp4.NewMediaSegment()
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frag, _ := mp4.CreateFragment(e.seqNumber, e.trackId)
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seg.AddFragment(frag)
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frag.AddFullSampleToTrack(mp4.FullSample{
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Sample: mp4.Sample{
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Dur: 4096, //TODO
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Size: uint32(len(packet)),
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},
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DecodeTime: uint64(4096 * e.seqNumber),
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Data: packet,
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}, e.trackId)
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seg.Encode(e.writer)
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e.seqNumber++
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}
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func (e *FormatEncoder) Write(pcm []byte) {
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if e.encoder == nil {
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return
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}
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e.buffer = append(e.buffer, pcm...)
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inputSize := e.encoder.GetInputSize()
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for len(e.buffer) >= inputSize {
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e.outputPacket(e.encoder.WritePacket(e.buffer[:inputSize]))
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e.buffer = e.buffer[inputSize:]
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}
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}
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func (e *FormatEncoder) Flush() {
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if e.encoder == nil {
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return
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}
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if len(e.buffer) > 0 {
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e.outputPacket(e.encoder.WritePacket(e.buffer))
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e.buffer = nil
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}
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//TODO: flush end
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}
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