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decode cue chunk (encoder's missing)
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,107 @@ | ||
| package wav | ||
|
|
||
| import ( | ||
| "bytes" | ||
| "encoding/binary" | ||
| "fmt" | ||
|
|
||
| "github.com/mattetti/audio/riff" | ||
| ) | ||
|
|
||
| // CuePoint defines an offset which marks a noteworthy sections of the audio | ||
| // content. For example, the beginning and end of a verse in a song may have cue | ||
| // points to make them easier to find. | ||
| type CuePoint struct { | ||
| // ID is the unique identifier of the cue point | ||
| ID [4]byte | ||
| // Play position specifies the sample offset associated with the cue point | ||
| // in terms of the sample's position in the final stream of samples | ||
| // generated by the play list. If a play list chunk is | ||
| // specified, the position value is equal to the sample number at which this | ||
| // cue point will occur during playback of the entire play list as defined | ||
| // by the play list's order. If no play list chunk is specified this value | ||
| // should be 0. | ||
| Position uint32 | ||
| // DataChunkID - This value specifies the four byte ID used by the chunk | ||
| // containing the sample that corresponds to this cue point. A Wave file | ||
| // with no play list is always "data". A Wave file with a play list | ||
| // containing both sample data and silence may be either "data" or "slnt". | ||
| DataChunkID [4]byte | ||
| // ChunkStart specifies the byte offset into the Wave List Chunk of the | ||
| // chunk containing the sample that corresponds to this cue point. This is | ||
| // the same chunk described by the Data Chunk ID value. If no Wave List | ||
| // Chunk exists in the Wave file, this value is 0. If a Wave List Chunk | ||
| // exists, this is the offset into the "wavl" chunk. The first chunk in the | ||
| // Wave List Chunk would be specified with a value of 0. | ||
| ChunkStart uint32 | ||
| // BlockStart specifies the byte offset into the "data" or "slnt" Chunk to | ||
| // the start of the block containing the sample. The start of a block is | ||
| // defined as the first byte in uncompressed PCM wave data or the last byte | ||
| // in compressed wave data where decompression can begin to find the value | ||
| // of the corresponding sample value. | ||
| BlockStart uint32 | ||
| // SampleOffset specifies an offset into the block (specified by Block | ||
| // Start) for the sample that corresponds to the cue point. In uncompressed | ||
| // PCM waveform data, this is simply the byte offset into the "data" chunk. | ||
| // In compressed waveform data, this value is equal to the number of samples | ||
| // (may or may not be bytes) from the Block Start to the sample that | ||
| // corresponds to the cue point. | ||
| SampleOffset uint32 | ||
| } | ||
|
|
||
| // DecodeCueChunk decodes the optional cue chunk and extracts cue points. | ||
| func DecodeCueChunk(d *Decoder, ch *riff.Chunk) error { | ||
| if ch == nil { | ||
| return fmt.Errorf("can't decode a nil chunk") | ||
| } | ||
| if d == nil { | ||
| return fmt.Errorf("nil decoder") | ||
| } | ||
| if ch.ID == CIDCue { | ||
| // read the entire chunk in memory | ||
| buf := make([]byte, ch.Size) | ||
| var err error | ||
| if _, err = ch.Read(buf); err != nil { | ||
| return fmt.Errorf("failed to read the CUE chunk - %v", err) | ||
| } | ||
| r := bytes.NewReader(buf) | ||
| var nbrCues uint32 | ||
| if err := binary.Read(r, binary.LittleEndian, &nbrCues); err != nil { | ||
| return fmt.Errorf("failed to read the number of cues - %v", err) | ||
| } | ||
| if nbrCues > 0 { | ||
| fmt.Println("nbrCues", nbrCues) | ||
| if d.Metadata == nil { | ||
| d.Metadata = &Metadata{} | ||
| } | ||
| d.Metadata.CuePoints = []*CuePoint{} | ||
| scratch := make([]byte, 4) | ||
| for i := uint32(0); i < nbrCues; i++ { | ||
| c := &CuePoint{} | ||
| if _, err = r.Read(scratch); err != nil { | ||
| return fmt.Errorf("failed to read the cue point ID") | ||
| } | ||
| copy(c.ID[:], scratch[:4]) | ||
| if err := binary.Read(r, binary.LittleEndian, &c.Position); err != nil { | ||
| return err | ||
| } | ||
| if _, err = r.Read(scratch); err != nil { | ||
| return fmt.Errorf("failed to read the data chunk id") | ||
| } | ||
| copy(c.DataChunkID[:], scratch[:4]) | ||
| if err := binary.Read(r, binary.LittleEndian, &c.ChunkStart); err != nil { | ||
| return err | ||
| } | ||
| if err := binary.Read(r, binary.LittleEndian, &c.BlockStart); err != nil { | ||
| return err | ||
| } | ||
| if err := binary.Read(r, binary.LittleEndian, &c.SampleOffset); err != nil { | ||
| return err | ||
| } | ||
| d.Metadata.CuePoints = append(d.Metadata.CuePoints, c) | ||
| } | ||
| } | ||
|
|
||
| } | ||
| return nil | ||
| } |
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,85 @@ | ||
| package wav_test | ||
|
|
||
| import ( | ||
| "os" | ||
| "reflect" | ||
| "testing" | ||
|
|
||
| "github.com/go-audio/wav" | ||
| ) | ||
|
|
||
| func TestDecoder_ReadMetadata(t *testing.T) { | ||
| testCases := []struct { | ||
| in string | ||
| metadata *wav.Metadata | ||
| }{ | ||
| {in: "fixtures/listinfo.wav", | ||
| metadata: &wav.Metadata{ | ||
| Artist: "artist", Title: "track title", Product: "album title", | ||
| TrackNbr: "42", CreationDate: "2017", Genre: "genre", Comments: "my comment", | ||
| }, | ||
| }, | ||
| {in: "fixtures/kick.wav"}, | ||
| {in: "fixtures/flloop.wav", metadata: &wav.Metadata{ | ||
| Software: "FL Studio (beta)", | ||
| CuePoints: []*wav.CuePoint{ | ||
| 0: {ID: [4]uint8{0x1, 0x0, 0x0, 0x0}, Position: 0x0, DataChunkID: [4]uint8{'d', 'a', 't', 'a'}}, | ||
| 1: {ID: [4]uint8{0x2, 0x0, 0x0, 0x0}, Position: 0x1a5e, DataChunkID: [4]uint8{'d', 'a', 't', 'a'}, SampleOffset: 0x1a5e}, | ||
| 2: {ID: [4]uint8{0x3, 0x0, 0x0, 0x0}, Position: 0x34bc, DataChunkID: [4]uint8{'d', 'a', 't', 'a'}, SampleOffset: 0x34bc}, | ||
| 3: {ID: [4]uint8{0x4, 0x0, 0x0, 0x0}, Position: 0x4f1a, DataChunkID: [4]uint8{'d', 'a', 't', 'a'}, SampleOffset: 0x4f1a}, | ||
| 4: {ID: [4]uint8{0x5, 0x0, 0x0, 0x0}, Position: 0x6978, DataChunkID: [4]uint8{'d', 'a', 't', 'a'}, SampleOffset: 0x6978}, | ||
| 5: {ID: [4]uint8{0x6, 0x0, 0x0, 0x0}, Position: 0x83d6, DataChunkID: [4]uint8{0x64, 0x61, 0x74, 0x61}, SampleOffset: 0x83d6}, | ||
| 6: {ID: [4]uint8{0x7, 0x0, 0x0, 0x0}, Position: 0x9e34, DataChunkID: [4]uint8{0x64, 0x61, 0x74, 0x61}, SampleOffset: 0x9e34}, | ||
| 7: {ID: [4]uint8{0x8, 0x0, 0x0, 0x0}, Position: 0xb892, DataChunkID: [4]uint8{0x64, 0x61, 0x74, 0x61}, SampleOffset: 0xb892}, | ||
| 8: {ID: [4]uint8{0x9, 0x0, 0x0, 0x0}, Position: 0xd2f0, DataChunkID: [4]uint8{0x64, 0x61, 0x74, 0x61}, SampleOffset: 0xd2f0}, | ||
| 9: {ID: [4]uint8{0xa, 0x0, 0x0, 0x0}, Position: 0xed4e, DataChunkID: [4]uint8{0x64, 0x61, 0x74, 0x61}, SampleOffset: 0xed4e}, | ||
| 10: {ID: [4]uint8{0xb, 0x0, 0x0, 0x0}, Position: 0x107ac, DataChunkID: [4]uint8{0x64, 0x61, 0x74, 0x61}, SampleOffset: 0x107ac}, | ||
| 11: {ID: [4]uint8{0xc, 0x0, 0x0, 0x0}, Position: 0x1220a, DataChunkID: [4]uint8{0x64, 0x61, 0x74, 0x61}, SampleOffset: 0x1220a}, | ||
| 12: {ID: [4]uint8{0xd, 0x0, 0x0, 0x0}, Position: 0x13c68, DataChunkID: [4]uint8{0x64, 0x61, 0x74, 0x61}, SampleOffset: 0x13c68}, | ||
| 13: {ID: [4]uint8{0xe, 0x0, 0x0, 0x0}, Position: 0x156c6, DataChunkID: [4]uint8{0x64, 0x61, 0x74, 0x61}, SampleOffset: 0x156c6}, | ||
| 14: {ID: [4]uint8{0xf, 0x0, 0x0, 0x0}, Position: 0x17124, DataChunkID: [4]uint8{0x64, 0x61, 0x74, 0x61}, SampleOffset: 0x17124}, | ||
| 15: {ID: [4]uint8{0x10, 0x0, 0x0, 0x0}, Position: 0x18b82, DataChunkID: [4]uint8{0x64, 0x61, 0x74, 0x61}, SampleOffset: 0x18b82}, | ||
| }, | ||
| SamplerInfo: &wav.SamplerInfo{SamplePeriod: 22676, MIDIUnityNote: 60, NumSampleLoops: 1, | ||
| Loops: []*wav.SampleLoop{ | ||
| {CuePointID: [4]byte{0, 0, 2, 0}, Type: 1024, Start: 0, End: 107999, Fraction: 0, PlayCount: 0}, | ||
| }}, | ||
| }}, | ||
| } | ||
|
|
||
| for _, tc := range testCases { | ||
| t.Run(tc.in, func(t *testing.T) { | ||
| f, err := os.Open(tc.in) | ||
| if err != nil { | ||
| t.Fatal(err) | ||
| } | ||
| d := wav.NewDecoder(f) | ||
| d.ReadMetadata() | ||
| if err = d.Err(); err != nil { | ||
| t.Fatal(err) | ||
| } | ||
| if tc.metadata != nil { | ||
| if tc.metadata.SamplerInfo != nil { | ||
| if !reflect.DeepEqual(tc.metadata.SamplerInfo, d.Metadata.SamplerInfo) { | ||
| t.Fatalf("Expected sampler info\n%#v to equal\n%#v\n", d.Metadata.SamplerInfo, tc.metadata.SamplerInfo) | ||
| } | ||
| } | ||
| if tc.metadata.CuePoints != nil { | ||
| if !reflect.DeepEqual(tc.metadata.CuePoints, d.Metadata.CuePoints) { | ||
| for i, c := range d.Metadata.CuePoints { | ||
| if !reflect.DeepEqual(c, tc.metadata.CuePoints[i]) { | ||
| t.Errorf("[%d] expected %#v got %#v", i, tc.metadata.CuePoints[i], c) | ||
| } | ||
| } | ||
| t.Errorf("Expected cue points\n%#v to equal\n%#v\n", d.Metadata.CuePoints, tc.metadata.CuePoints) | ||
| } | ||
| } | ||
|
|
||
| if !reflect.DeepEqual(tc.metadata, d.Metadata) { | ||
| t.Fatalf("Expected\n%#v\n to equal\n%#v\n", d.Metadata, tc.metadata) | ||
| } | ||
| } | ||
| f.Close() | ||
| }) | ||
| } | ||
| } |