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https://github.com/wader/fq.git
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7c5215347d
Remove bitio.Buffer layer. bitio.Buffer was a kitchen sink layer with helpers now it's just a buffer and most functions have been moved to decode instead. bitio package now only have primitive types and functions simialar to standard library io and bytes packages. Make nearly eveything internally use bitio.Bit* interfaces so that slicing work correctly this will also make it possible to start experimenting with more complicated silcing helpers, ex things like: breplace(.header.bitrate; 123) to get a new buffer with bitrate changed.
89 lines
2.7 KiB
Go
89 lines
2.7 KiB
Go
package flac
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// https://xiph.org/flac/format.html
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// https://wiki.hydrogenaud.io/index.php?title=FLAC_decoder_testbench
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// TODO:
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// 16 - Part 6 of Ladybug Castle (partition order 8 with escape codes)
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// 32 - Part 5 of The Four of Us Are Dying (partition order 8 with escape codes)
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import (
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"bytes"
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"crypto/md5"
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"fmt"
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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/internal/mathextra"
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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/scalar"
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)
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var flacMetadatablocksFormat decode.Group
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var flacFrameFormat decode.Group
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func init() {
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registry.MustRegister(decode.Format{
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Name: format.FLAC,
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Description: "Free Lossless Audio Codec file",
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Groups: []string{format.PROBE},
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DecodeFn: flacDecode,
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Dependencies: []decode.Dependency{
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{Names: []string{format.FLAC_METADATABLOCKS}, Group: &flacMetadatablocksFormat},
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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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func flacDecode(d *decode.D, in interface{}) interface{} {
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d.FieldUTF8("magic", 4, d.AssertStr("fLaC"))
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var streamInfo format.FlacStreamInfo
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var flacFrameIn format.FlacFrameIn
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var framesNDecodedSamples uint64
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var streamTotalSamples uint64
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var streamDecodedSamples uint64
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_, v := d.FieldFormat("metadatablocks", flacMetadatablocksFormat, nil)
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flacMetadatablockOut, ok := v.(format.FlacMetadatablocksOut)
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if !ok {
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panic(fmt.Sprintf("expected FlacMetadatablockOut got %#+v", v))
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}
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if flacMetadatablockOut.HasStreamInfo {
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streamInfo = flacMetadatablockOut.StreamInfo
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streamTotalSamples = streamInfo.TotalSamplesInStream
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flacFrameIn = format.FlacFrameIn{StreamInfo: streamInfo}
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}
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md5Samples := md5.New()
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d.FieldArray("frames", func(d *decode.D) {
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for d.NotEnd() {
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// flac frame might need some fields from stream info to decode
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_, v := d.FieldFormat("frame", flacFrameFormat, flacFrameIn)
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ffo, ok := v.(format.FlacFrameOut)
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if !ok {
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panic(fmt.Sprintf("expected FlacFrameOut got %#+v", v))
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}
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samplesInFrame := ffo.Samples
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if streamTotalSamples > 0 {
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samplesInFrame = mathextra.MinUInt64(streamTotalSamples-streamDecodedSamples, ffo.Samples)
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}
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frameStreamSamplesBuf := ffo.SamplesBuf[0 : samplesInFrame*uint64(ffo.Channels*ffo.BitsPerSample/8)]
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framesNDecodedSamples += ffo.Samples
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d.MustCopy(md5Samples, bytes.NewReader(frameStreamSamplesBuf))
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streamDecodedSamples += ffo.Samples
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// reuse buffer if possible
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flacFrameIn.SamplesBuf = ffo.SamplesBuf
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}
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})
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md5CalcValue := d.FieldRootBitBuf("md5_calculated", bitio.NewBitReader(md5Samples.Sum(nil), -1))
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_ = md5CalcValue.TryScalarFn(d.ValidateBitBuf(streamInfo.MD5), scalar.RawHex)
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d.FieldValueU("decoded_samples", framesNDecodedSamples)
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return nil
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}
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