74 lines
1.9 KiB
Go
74 lines
1.9 KiB
Go
// Helper functions for extracting pcm audio from web and local sources.
|
|
package dca0
|
|
|
|
import (
|
|
"errors"
|
|
"io"
|
|
"os/exec"
|
|
"strconv"
|
|
)
|
|
|
|
type PcmOptions struct {
|
|
FfmpegPath string
|
|
Channels int
|
|
SampleRate int
|
|
// Seek means where to start in seconds.
|
|
Seek float32
|
|
// Duration means where to stop (in seconds after the time specified by Seek).
|
|
// If Duration is set to 0, the stream will ignore it and encode all the way
|
|
// to the end of the input.
|
|
Duration float32
|
|
}
|
|
|
|
func getDefaultPcmOptions(ffmpegPath string) PcmOptions {
|
|
return PcmOptions{
|
|
FfmpegPath: ffmpegPath,
|
|
Channels: 2,
|
|
// 48000 is the only one used by discord currently.
|
|
SampleRate: 48000,
|
|
Seek: 0,
|
|
Duration: 0,
|
|
}
|
|
}
|
|
|
|
// Input can be either a local file or an http(s) address. It can be of any
|
|
// audio format supported by ffmpeg.
|
|
// Wait must be called on the returned command to free its resources after
|
|
// everything has been read.
|
|
func getPcm(input string, opts PcmOptions) (io.ReadCloser, *exec.Cmd, error) {
|
|
if input == "" {
|
|
return nil, nil, errors.New("dca0.getPcm() called with empty input")
|
|
}
|
|
var cmdOpts []string
|
|
cmdOpts = append(cmdOpts, []string{
|
|
"-vn", // No video.
|
|
"-sn", // No subtitle.
|
|
"-dn", // No data encoding.
|
|
}...)
|
|
if opts.Seek != 0.0 {
|
|
cmdOpts = append(cmdOpts,
|
|
"-accurate_seek",
|
|
"-ss", strconv.FormatFloat(float64(opts.Seek), 'f', 5, 32))
|
|
}
|
|
if opts.Duration != 0.0 {
|
|
cmdOpts = append(cmdOpts,
|
|
"-t", strconv.FormatFloat(float64(opts.Duration), 'f', 5, 32))
|
|
}
|
|
cmdOpts = append(cmdOpts, []string{
|
|
"-i", input,
|
|
"-f", "s16le", // Signed int16 samples.
|
|
"-ar", strconv.Itoa(opts.SampleRate),
|
|
"-ac", strconv.Itoa(opts.Channels), // Number of audio channels.
|
|
"pipe:1", // Output to stdout.
|
|
}...)
|
|
cmd := exec.Command(opts.FfmpegPath, cmdOpts...)
|
|
stdout, err := cmd.StdoutPipe()
|
|
if err != nil {
|
|
return nil, nil, err
|
|
}
|
|
if err := cmd.Start(); err != nil {
|
|
return nil, nil, err
|
|
}
|
|
return stdout, cmd, nil
|
|
}
|