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metadata.go
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metadata.go
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package wav
// Metadata represents optional metadata added to the wav file.
type Metadata struct {
SamplerInfo *SamplerInfo
// Artist of the original subject of the file. For example, Michaelangelo.
Artist string
// Comments provides general comments about the file or the subject of the
// file. If the comment is several sentences long, end each sentence with a
// period. Do not include newline characters.
Comments string
// Copyright records the copyright information for the file.
Copyright string
// CreationDate specifies the date the subject of the file was created. List
// dates in year-month-day format, padding one-digit months and days with a
// zero on the left. For example: 1553-05-03 for May 3, 1553. The year
// should always be given using four digits.
CreationDate string
// Engineer stores the name of the engineer who worked on the file. If there
// are multiple engineers, separate the names by a semicolon and a blank.
// For example: Smith, John; Adams, Joe.
Engineer string
// Technician identifies the technician who sampled the subject file. For
// example: Smith, John.
Technician string
// Genre describes the original work, such as jazz, classical, rock, etc.
Genre string
// Keywords provides a list of keywords that refer to the file or subject of
// the file. Separate multiple keywords with a semicolon and a blank. For
// example, Seattle; zoology; The Civil War.
Keywords string
// Medium describes the original subject of the file, such as record, CD and so forth.
Medium string
// Title stores the title of the subject of the file, such as bohemian rhapsody.
Title string
// Product AKA album specifies the name of the title the file was originally
// intended for: A Night at the Opera
Product string
// Subject describes the contents of the file, such as Metadata Management.
Subject string
// Software identifies the name of the software package used to create the
// file, such as go-audio.
Software string
// Source identifies the name of the person or organization who supplied the
// original subject of the file. For example: Splice.
Source string
// Location or Archival Location - Indicates where the subject of the file is archived.
Location string
// TrackNbr is the track number
TrackNbr string
// CuePoints is a list of cue points in the wav file.
CuePoints []*CuePoint
}
// SamplerInfo is extra metadata pertinent to a sampler type usage.
type SamplerInfo struct {
// Manufacturer field specifies the MIDI Manufacturer's Association
// (MMA) Manufacturer code for the sampler intended to receive this file's
// waveform. Each manufacturer of a MIDI product is assigned a unique ID
// which identifies the company. If no particular manufacturer is to be
// specified, a value of 0 should be used. The value is stored with some
// extra information to enable translation to the value used in a MIDI
// System Exclusive transmission to the sampler. The high byte indicates the
// number of low order bytes (1 or 3) that are valid for the manufacturer
// code. For example, the value for Digidesign will be 0x01000013 (0x13) and
// the value for Microsoft will be 0x30000041 (0x00, 0x00, 0x41).
Manufacturer [4]byte
// Product field specifies the MIDI model ID defined by the manufacturer
// corresponding to the Manufacturer field. Contact the manufacturer of the
// sampler to get the model ID. If no particular manufacturer's product is
// to be specified, a value of 0 should be used.
Product [4]byte
// SamplePeriod The sample period specifies the duration of time that passes
// during the playback of one sample in nanoseconds (normally equal to 1 /
// Samplers Per Second, where Samples Per Second is the value found in the
// format chunk).
SamplePeriod uint32
// MIDIUnityNote The MIDI unity note value has the same meaning as the instrument chunk's
// MIDI Unshifted Note field which specifies the musical note at which the
// sample will be played at it's original sample rate (the sample rate
// specified in the format chunk).
MIDIUnityNote uint32
// MIDIPitchFraction The MIDI pitch fraction specifies the fraction of a
// semitone up from the specified MIDI unity note field. A value of
// 0x80000000 means 1/2 semitone (50 cents) and a value of 0x00000000 means
// no fine tuning between semitones.
MIDIPitchFraction uint32
// SMPTEFormat The SMPTE format specifies the Society of Motion Pictures and
// Television E time format used in the following SMPTE Offset field. If a
// value of 0 is set, SMPTE Offset should also be set to 0. (0, 24, 25, 29, 30)
SMPTEFormat uint32
// SMPTEOffset The SMPTE Offset value specifies the time offset to be used
// for the synchronization / calibration to the first sample in the
// waveform. This value uses a format of 0xhhmmssff where hh is a signed
// value that specifies the number of hours (-23 to 23), mm is an unsigned
// value that specifies the number of minutes (0 to 59), ss is an unsigned
// value that specifies the number of seconds (0 to 59) and ff is an
// unsigned value that specifies the number of frames (0 to -1).
SMPTEOffset uint32
// NumSampleLoops The sample loops field specifies the number Sample Loop
// definitions in the following list. This value may be set to 0 meaning
// that no sample loops follow.
NumSampleLoops uint32
// Loops A list of sample loops is simply a set of consecutive loop
// descriptions. The sample loops do not have to be in any particular order
// because each sample loop associated cue point position is used to
// determine the play order.
Loops []*SampleLoop
}
// SampleLoop indicates a loop and its properties within the audio file
type SampleLoop struct {
// CuePointID - The Cue Point ID specifies the unique ID that corresponds to one of the
// defined cue points in the cue point list. Furthermore, this ID
// corresponds to any labels defined in the associated data list chunk which
// allows text labels to be assigned to the various sample loops.
CuePointID [4]byte
// Type - The type field defines how the waveform samples will be looped.
// 0 Loop forward (normal)
// 1 Alternating loop (forward/backward, also known as Ping Pong)
// 2 Loop backward (reverse)
// 3 Reserved for future standard types
// 32 - 0xFFFFFFFF Sampler specific types (defined by manufacturer)
Type uint32
// Start - The start value specifies the byte offset into the waveform data
// of the first sample to be played in the loop.
Start uint32
// End - The end value specifies the byte offset into the waveform data of
// the last sample to be played in the loop.
End uint32
// Fraction - The fractional value specifies a fraction of a sample at which
// to loop. This allows a loop to be fine tuned at a resolution greater than
// one sample. The value can range from 0x00000000 to 0xFFFFFFFF. A value of
// 0 means no fraction, a value of 0x80000000 means 1/2 of a sample length.
// 0xFFFFFFFF is the smallest fraction of a sample that can be represented.
Fraction uint32
// PlayCount - The play count value determines the number of times to play
// the loop. A value of 0 specifies an infinite sustain loop. An infinite
// sustain loop will continue looping until some external force interrupts
// playback, such as the musician releasing the key that triggered the
// wave's playback. All other values specify an absolute number of times to
// loop.
PlayCount uint32
}