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120 lines
3.7 KiB
Go
120 lines
3.7 KiB
Go
package flac
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// TODO: 24 bit picture length truncate warning
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import (
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"github.com/wader/fq/format"
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"github.com/wader/fq/format/registry"
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"github.com/wader/fq/pkg/decode"
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"github.com/wader/fq/pkg/ranges"
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)
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var flacPicture []*decode.Format
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var vorbisCommentFormat []*decode.Format
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func init() {
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registry.MustRegister(&decode.Format{
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Name: format.FLAC_METADATABLOCKS,
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Description: "FLAC metadatablocks",
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DecodeFn: metadatablocskDecode,
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RootV: decode.Array{},
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RootName: "metadatablocks",
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Dependencies: []decode.Dependency{
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{Names: []string{format.FLAC_PICTURE}, Formats: &flacPicture},
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{Names: []string{format.VORBIS_COMMENT}, Formats: &vorbisCommentFormat},
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},
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})
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}
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const (
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MetadataBlockStreaminfo = 0
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MetadataBlockPadding = 1
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MetadataBlockApplication = 2
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MetadataBlockSeektable = 3
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MetadataBlockVorbisComment = 4
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MetadataBlockCuesheet = 5
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MetadataBlockPicture = 6
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)
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var metadataBlockNames = map[uint]string{
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MetadataBlockStreaminfo: "Streaminfo",
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MetadataBlockPadding: "Padding",
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MetadataBlockApplication: "Application",
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MetadataBlockSeektable: "Seektable",
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MetadataBlockVorbisComment: "Vorbis comment",
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MetadataBlockCuesheet: "Cuesheet",
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MetadataBlockPicture: "Picture",
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}
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func metadatablocskDecode(d *decode.D, in interface{}) interface{} {
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mb := format.FlacMetadatablocksOut{}
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isLastBlock := false
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for !isLastBlock {
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d.FieldStructFn("metadatablock", func(d *decode.D) {
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isLastBlock = d.FieldBool("last_block")
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typ := d.FieldUFn("type", func() (uint64, decode.DisplayFormat, string) {
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t := d.U7()
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name := "Unknown"
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if s, ok := metadataBlockNames[uint(t)]; ok {
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name = s
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}
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return t, decode.NumberDecimal, name
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})
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length := d.FieldU24("length")
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switch typ {
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case MetadataBlockStreaminfo:
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d.FieldU16("minimum_block_size")
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d.FieldU16("maximum_block_size")
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d.FieldU24("minimum_frame_size")
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d.FieldU24("maximum_frame_size")
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sampleRate := d.FieldU("sample_rate", 20)
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// <3> (number of channels)-1. FLAC supports from 1 to 8 channels
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d.FieldUFn("channels", func() (uint64, decode.DisplayFormat, string) { return d.U3() + 1, decode.NumberDecimal, "" })
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// <5> (bits per sample)-1. FLAC supports from 4 to 32 bits per sample. Currently the reference encoder and decoders only support up to 24 bits per sample.
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bitPerSample := d.FieldUFn("bits_per_sample", func() (uint64, decode.DisplayFormat, string) {
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return d.U5() + 1, decode.NumberDecimal, ""
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})
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totalSamplesInStream := d.FieldU("total_samples_in_stream", 36)
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md5Range := ranges.Range{Start: d.Pos(), Len: 16 * 8}
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d.FieldBitBufLen("md5", 16*8)
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mb.StreamInfo = format.FlacMetadatablockStreamInfo{
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SampleRate: sampleRate,
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BitPerSample: bitPerSample,
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TotalSamplesInStream: totalSamplesInStream,
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MD5Range: md5Range,
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}
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mb.HasStreamInfo = true
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case MetadataBlockVorbisComment:
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d.FieldFormatLen("comment", int64(length*8), vorbisCommentFormat, nil)
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case MetadataBlockPicture:
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d.FieldFormatLen("picture", int64(length*8), flacPicture, nil)
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case MetadataBlockSeektable:
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seektableCount := length / 18
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d.FieldArrayFn("seekpoints", func(d *decode.D) {
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for i := uint64(0); i < seektableCount; i++ {
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d.FieldStructFn("seekpoint", func(d *decode.D) {
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d.FieldUFn("sample_number", func() (uint64, decode.DisplayFormat, string) {
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n := d.U64()
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d := ""
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if n == 0xffffffffffffffff {
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d = "Placeholder"
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}
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return n, decode.NumberDecimal, d
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})
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d.FieldU64("offset")
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d.FieldU16("number_of_samples")
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})
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}
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})
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default:
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d.FieldBitBufLen("data", int64(length*8))
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}
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})
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}
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return mb
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}
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