mirror of
https://github.com/wader/fq.git
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9b81d4d3ab
Preparation to make decoder use less memory and API more type safe. Now each scalar type has it's own struct type so it can store different things and enables to have a scalar interface. Also own types will enable experimenting with decode DLS designs like using chained methods that are type aware.
180 lines
4.9 KiB
Go
180 lines
4.9 KiB
Go
package ogg
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// https://xiph.org/ogg/doc/framing.html
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import (
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"bytes"
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"fmt"
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"github.com/wader/fq/format"
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"github.com/wader/fq/pkg/bitio"
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"github.com/wader/fq/pkg/decode"
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"github.com/wader/fq/pkg/interp"
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)
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var oggPageFormat decode.Group
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var vorbisPacketFormat decode.Group
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var opusPacketFormat decode.Group
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var flacMetadatablockFormat decode.Group
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var flacFrameFormat decode.Group
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func init() {
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interp.RegisterFormat(decode.Format{
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Name: format.OGG,
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Description: "OGG file",
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Groups: []string{format.PROBE},
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DecodeFn: decodeOgg,
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Dependencies: []decode.Dependency{
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{Names: []string{format.OGG_PAGE}, Group: &oggPageFormat},
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{Names: []string{format.VORBIS_PACKET}, Group: &vorbisPacketFormat},
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{Names: []string{format.OPUS_PACKET}, Group: &opusPacketFormat},
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{Names: []string{format.FLAC_METADATABLOCK}, Group: &flacMetadatablockFormat},
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{Names: []string{format.FLAC_FRAME}, Group: &flacFrameFormat},
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},
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})
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}
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var (
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vorbisIdentification = []byte("\x01vorbis")
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opusIdentification = []byte("OpusHead")
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flacIdentification = []byte("\x7fFLAC")
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)
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type streamCodec int
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const (
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codecUnknown streamCodec = iota
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codecVorbis
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codecOpus
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codecFlac
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)
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type stream struct {
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sequenceNo uint32
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packetBuf []byte
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packetD *decode.D
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codec streamCodec
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flacStreamInfo format.FlacStreamInfo
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}
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func decodeOgg(d *decode.D, _ any) any {
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validPages := 0
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streams := map[uint32]*stream{}
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streamsD := d.FieldArrayValue("streams")
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d.FieldArray("pages", func(d *decode.D) {
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for !d.End() {
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_, dv, _ := d.TryFieldFormat("page", oggPageFormat, nil)
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if dv == nil {
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break
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}
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oggPageOut, ok := dv.(format.OggPageOut)
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if !ok {
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panic("page decode is not a oggPageOut")
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}
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s, sFound := streams[oggPageOut.StreamSerialNumber]
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if !sFound {
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var packetsD *decode.D
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streamsD.FieldStruct("stream", func(d *decode.D) {
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d.FieldValueUint("serial_number", uint64(oggPageOut.StreamSerialNumber))
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packetsD = d.FieldArrayValue("packets")
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})
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s = &stream{
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sequenceNo: oggPageOut.SequenceNo,
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packetD: packetsD,
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codec: codecUnknown,
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}
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streams[oggPageOut.StreamSerialNumber] = s
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}
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// if !sFound && !oggPageOut.IsFirstPage {
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// // TODO: not first page and we haven't seen the stream before
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// // log.Println("not first page and we haven't seen the stream before")
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// }
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// hasData := len(s.packetBuf) > 0
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// if oggPageOut.IsContinuedPacket && !hasData {
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// // TODO: continuation but we haven't seen any packet data yet
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// // log.Println("continuation but we haven't seen any packet data yet")
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// }
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// if !oggPageOut.IsFirstPage && s.sequenceNo+1 != oggPageOut.SequenceNo {
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// // TODO: page gap
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// // log.Println("page gap")
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// }
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for _, bs := range oggPageOut.Segments {
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s.packetBuf = append(s.packetBuf, bs...)
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if len(bs) < 255 {
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br := bitio.NewBitReader(s.packetBuf, -1)
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if s.codec == codecUnknown {
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if bytes.HasPrefix(s.packetBuf, vorbisIdentification) {
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s.codec = codecVorbis
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} else if bytes.HasPrefix(s.packetBuf, opusIdentification) {
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s.codec = codecOpus
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} else if bytes.HasPrefix(s.packetBuf, flacIdentification) {
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s.codec = codecFlac
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}
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}
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switch s.codec {
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case codecVorbis:
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// TODO: err
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if _, _, err := s.packetD.TryFieldFormatBitBuf("packet", br, vorbisPacketFormat, nil); err != nil {
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s.packetD.FieldRootBitBuf("packet", br)
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}
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case codecOpus:
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// TODO: err
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if _, _, err := s.packetD.TryFieldFormatBitBuf("packet", br, opusPacketFormat, nil); err != nil {
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s.packetD.FieldRootBitBuf("packet", br)
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}
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case codecFlac:
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if len(s.packetBuf) == 0 {
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return
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}
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switch {
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case s.packetBuf[0] == 0x7f:
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s.packetD.FieldStructRootBitBufFn("packet", br, func(d *decode.D) {
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d.FieldU8("type")
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d.FieldUTF8("signature", 4)
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d.FieldU8("major")
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d.FieldU8("minor")
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d.FieldU16("header_packets")
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d.FieldUTF8("flac_signature", 4)
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dv, v := d.FieldFormat("metadatablock", flacMetadatablockFormat, nil)
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flacMetadatablockOut, ok := v.(format.FlacMetadatablockOut)
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if dv != nil && !ok {
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panic(fmt.Sprintf("expected FlacMetadatablockOut, got %#+v", flacMetadatablockOut))
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}
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s.flacStreamInfo = flacMetadatablockOut.StreamInfo
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})
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case s.packetBuf[0] == 0xff:
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s.packetD.FieldFormatBitBuf("packet", br, flacFrameFormat, nil)
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default:
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s.packetD.FieldFormatBitBuf("packet", br, flacMetadatablockFormat, nil)
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}
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case codecUnknown:
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s.packetD.FieldRootBitBuf("packet", br)
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}
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s.packetBuf = nil
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}
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}
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s.sequenceNo = oggPageOut.SequenceNo
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if oggPageOut.IsLastPage {
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delete(streams, oggPageOut.StreamSerialNumber)
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}
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validPages++
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}
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})
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if validPages == 0 {
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d.Fatalf("no pages found")
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}
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return nil
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}
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