58 lines
2.1 KiB
Go
58 lines
2.1 KiB
Go
package audio
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// SampleRate is the number of audio samples a Streamer should produce per one second of audio.
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//
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// This value should be set at most once before using audio package. It is safe to assume that this
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// value does not change during runtime.
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var SampleRate float64 = 48000
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// Streamer is able to stream a finite or infinite sequence of audio samples.
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type Streamer interface {
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// Stream copies at most len(samples) next audio samples to the samples slice.
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//
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// The sample rate of the samples is specified by the global SampleRate variable/constant.
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// The value at samples[i][0] is the value of the left channel of the i-th sample.
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// Similarly, samples[i][1] is the value of the right channel of the i-th sample.
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//
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// Stream returns the number of streamed samples. If the Streamer is drained and no more
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// samples will be produced, it returns 0 and false. Stream must not touch any samples
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// outside samples[:n].
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//
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// There are 3 valid return pattterns of the Stream method:
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//
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// 1. n == len(samples) && ok
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//
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// Stream streamed all of the requested samples. Cases 1, 2 and 3 may occur in the following
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// calls.
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//
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// 2. 0 < n && n < len(samples) && ok
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//
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// Stream streamed n samples and drained the Streamer. Only case 3 may occur in the
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// following calls.
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//
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// 3. n == 0 && !ok
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//
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// The Streamer is drained and no more samples will come. Only this case may occur in the
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// following calls.
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Stream(samples [][2]float64) (n int, ok bool)
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}
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// StreamerFunc is a Streamer created by simply wrapping a streaming function (usually a closure,
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// which encloses a time tracking variable). This sometimes simplifies creating new streamers.
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//
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// Example:
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//
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// noise := StreamerFunc(func(samples [][2]float64) (n int, ok bool) {
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// for i := range samples {
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// samples[i][0] = rand.Float64()*2 - 1
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// samples[i][1] = rand.Float64()*2 - 1
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// }
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// return len(samples), true
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// })
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type StreamerFunc func(samples [][2]float64) (n int, ok bool)
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// Stream calls the wrapped streaming function.
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func (sf StreamerFunc) Stream(samples [][2]float64) (n int, ok bool) {
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return sf(samples)
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}
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