Files
gortsplib/pkg/formats/opus.go
2023-08-16 13:26:17 +02:00

117 lines
2.4 KiB
Go

package formats
import (
"fmt"
"strconv"
"strings"
"github.com/pion/rtp"
"github.com/bluenviron/gortsplib/v4/pkg/formats/rtpsimpleaudio"
)
// Opus is a RTP format for the Opus codec.
// Specification: https://datatracker.ietf.org/doc/html/rfc7587
type Opus struct {
PayloadTyp uint8
IsStereo bool
}
func (f *Opus) unmarshal(payloadType uint8, clock string, _ string, _ string, fmtp map[string]string) error {
f.PayloadTyp = payloadType
tmp := strings.SplitN(clock, "/", 2)
if len(tmp) != 2 {
return fmt.Errorf("invalid clock (%v)", clock)
}
sampleRate, err := strconv.ParseUint(tmp[0], 10, 31)
if err != nil || sampleRate != 48000 {
return fmt.Errorf("invalid sample rate: %d", sampleRate)
}
channelCount, err := strconv.ParseUint(tmp[1], 10, 31)
if err != nil || channelCount != 2 {
return fmt.Errorf("invalid channel count: %d", channelCount)
}
for key, val := range fmtp {
if key == "sprop-stereo" {
f.IsStereo = (val == "1")
}
}
return nil
}
// Codec implements Format.
func (f *Opus) Codec() string {
return "Opus"
}
// ClockRate implements Format.
func (f *Opus) ClockRate() int {
// RFC7587: the RTP timestamp is incremented with a 48000 Hz
// clock rate for all modes of Opus and all sampling rates.
return 48000
}
// PayloadType implements Format.
func (f *Opus) PayloadType() uint8 {
return f.PayloadTyp
}
// RTPMap implements Format.
func (f *Opus) RTPMap() string {
// RFC7587: The RTP clock rate in "a=rtpmap" MUST be 48000, and the
// number of channels MUST be 2.
return "opus/48000/2"
}
// FMTP implements Format.
func (f *Opus) FMTP() map[string]string {
fmtp := map[string]string{
"sprop-stereo": func() string {
if f.IsStereo {
return "1"
}
return "0"
}(),
}
return fmtp
}
// PTSEqualsDTS implements Format.
func (f *Opus) PTSEqualsDTS(*rtp.Packet) bool {
return true
}
// CreateDecoder creates a decoder able to decode the content of the format.
func (f *Opus) CreateDecoder() (*rtpsimpleaudio.Decoder, error) {
d := &rtpsimpleaudio.Decoder{
SampleRate: 48000,
}
err := d.Init()
if err != nil {
return nil, err
}
return d, nil
}
// CreateEncoder creates an encoder able to encode the content of the format.
func (f *Opus) CreateEncoder() (*rtpsimpleaudio.Encoder, error) {
e := &rtpsimpleaudio.Encoder{
PayloadType: f.PayloadTyp,
SampleRate: 48000,
}
err := e.Init()
if err != nil {
return nil, err
}
return e, nil
}