103 lines
2.2 KiB
Go
103 lines
2.2 KiB
Go
package audio
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import (
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"os/exec"
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"fmt"
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"regexp"
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"runtime"
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"io"
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)
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type microphone struct {
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command *exec.Cmd
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audioStream io.Reader
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diagnosticOutput io.Reader
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Format string
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Device string
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Encoding Encoding
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}
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func NewMicrophone() (*microphone, error) {
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if runtime.GOOS != "darwin" {
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panic(fmt.Errorf("audio.microphone is only supported on macOS"))
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}
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format := "avfoundation"
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device, err := getMicDevice(format)
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if err != nil {
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return nil, err
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}
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return µphone{
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Format: format,
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Device: device,
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Encoding: defaultEncoding,
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}, nil
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}
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func (m *microphone) Start() error {
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m.command = exec.Command("ffmpeg", "-re",
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"-f", m.Format,
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"-i", fmt.Sprintf(":%s", m.Device),
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"-f", m.Encoding.Codec,
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"-ar", fmt.Sprintf("%d", m.Encoding.Bitrate),
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"-ac", fmt.Sprintf("%d", m.Encoding.Channels),
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"-",
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)
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// these should never fail, unless you use the module incorrectly
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audioStream, err := m.command.StdoutPipe()
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if err != nil {
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panic(err)
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}
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diagnosticOutput, err := m.command.StderrPipe()
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if err != nil {
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panic(err)
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}
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m.audioStream, m.diagnosticOutput = audioStream, diagnosticOutput
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return m.command.Start()
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}
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func (m *microphone) Stop() error {
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return m.command.Process.Kill()
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}
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func (m *microphone) AudioStream() io.Reader {
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if m.audioStream == nil {
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panic(fmt.Errorf("AudioStream() called before Start()"))
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}
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return m.audioStream
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}
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func (m *microphone) DiagnosticOutput() io.Reader {
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if m.diagnosticOutput == nil {
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panic(fmt.Errorf("DiagnosticOutput() called before Start()"))
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}
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return m.diagnosticOutput
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}
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func getMicDevice(format string) (string, error) {
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cmd := exec.Command("ffmpeg",
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"-f", format,
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"-list_devices", "true",
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"-i", "\"\"",
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)
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// ignore error, this ffmpeg command returns exit status 1
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outputBytes, _ := cmd.CombinedOutput()
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output := string(outputBytes)
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parsedOutput := parseDeviceNumber(output)
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if parsedOutput == "" {
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return "", fmt.Errorf("Command: %s\nFailed to parse FFmpeg output:\n%s", cmd, output)
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}
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return parsedOutput, nil
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}
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func parseDeviceNumber(ffmpegOutput string) string {
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re := regexp.MustCompile(`\[(\d)\].*?[Mm]icrophone`)
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matches := re.FindStringSubmatch(ffmpegOutput)
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if (len(matches) == 2) {
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return matches[1]
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}
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return ""
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}
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