codec.go

package meowcaller

import "github.com/purpshell/meowcaller/signaling"

// AudioCodec identifies the wire audio codec negotiated for a call. WhatsApp 1:1
// audio is carried in RTP payload type 120 regardless of codec; the codec itself
// is chosen by signaling (the server's voip_settings), not the RTP payload type.
type AudioCodec int8

const (
	// AudioCodecMlow is Meta's 16 kHz MLow codec (the default).
	AudioCodecMlow AudioCodec = iota
	// AudioCodecOpus is RFC 6716 Opus.
	AudioCodecOpus
)

// String renders the codec name for logs.
func (c AudioCodec) String() string {
	switch c {
	case AudioCodecOpus:
		return "opus"
	default:
		return "mlow"
	}
}

// selectAudioCodec maps parsed voip_settings to the codec the media loop should
// use. Absent settings or an explicit MLow selection keep the call on MLow; only
// use_mlow_codec_v1=false switches it to Opus.
func selectAudioCodec(vs *signaling.VoipSettings) AudioCodec {
	if vs == nil || !vs.Present || vs.UseMlowCodecV1 {
		return AudioCodecMlow
	}
	return AudioCodecOpus
}