88 lines
1.7 KiB
Go
88 lines
1.7 KiB
Go
package sound
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import (
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"context"
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"fmt"
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"io"
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"os/exec"
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)
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// FMConfig defines the tunables for an FM instance
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type FMConfig struct {
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Frequency float32
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}
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// FM is a sound.Output implementation that outputs to an FM frequency
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type FM struct {
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config *FMConfig
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}
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// NewFM creates a new FM instance with the given config
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func NewFM(config FMConfig) *FM {
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return &FM{
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config: &config,
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}
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}
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// Play the given input to the FM frequency
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func (f *FM) Play(ctx context.Context, filePath string) error {
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ctx, cancel := context.WithCancel(ctx)
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defer cancel()
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soxCmd := exec.CommandContext(
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ctx,
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"sox",
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filePath,
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"-r", "22050",
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"-c", "1",
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"-b", "16",
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"-t", "wav",
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"-",
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)
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reader, err := soxCmd.StdoutPipe()
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if err != nil {
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return fmt.Errorf("failed to open STDOUT pipe for converting the input file to the FM transmitter format: %w", err)
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}
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err = soxCmd.Start()
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if err != nil {
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return fmt.Errorf("failed to start conversion for the input file for the FM transmitter: %w", err)
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}
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fmCmd := exec.CommandContext(
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ctx,
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"fm_transmitter",
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"-f",
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fmt.Sprintf("%.1f", f.config.Frequency),
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"-",
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)
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writer, err := fmCmd.StdinPipe()
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if err != nil {
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return fmt.Errorf("failed to create STDIN pipe for FM transmitter: %w", err)
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}
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err = fmCmd.Start()
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if err != nil {
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return fmt.Errorf("failed to start FM transmitter command: %w", err)
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}
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_, err = io.Copy(writer, reader)
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if err != nil {
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return fmt.Errorf("failed to write audio output to FM transmitter: %w", err)
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}
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err = soxCmd.Wait()
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if err != nil {
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return fmt.Errorf("audio conversion command resulted in an error: %w", err)
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}
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err = fmCmd.Wait()
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if err != nil {
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return fmt.Errorf("FM transmitter command resulted in an error: %w", err)
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}
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return nil
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}
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