merge format and formatdecenc into formats (#222)

pkg/formats/opus.go

@@ -0,0 +1,107 @@
+package formats
+
+import (
+	"fmt"
+	"strconv"
+	"strings"
+
+	"github.com/pion/rtp"
+
+	"github.com/bluenviron/gortsplib/v3/pkg/formats/rtpsimpleaudio"
+)
+
+// Opus is a format that uses the Opus codec.
+type Opus struct {
+	PayloadTyp uint8
+	IsStereo   bool
+}
+
+// String implements Format.
+func (t *Opus) String() string {
+	return "Opus"
+}
+
+// ClockRate implements Format.
+func (t *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 (t *Opus) PayloadType() uint8 {
+	return t.PayloadTyp
+}
+
+func (t *Opus) unmarshal(payloadType uint8, clock string, codec string, rtpmap string, fmtp map[string]string) error {
+	t.PayloadTyp = payloadType
+
+	tmp := strings.SplitN(clock, "/", 2)
+	if len(tmp) != 2 {
+		return fmt.Errorf("invalid clock (%v)", clock)
+	}
+
+	sampleRate, err := strconv.ParseInt(tmp[0], 10, 64)
+	if err != nil {
+		return err
+	}
+	if sampleRate != 48000 {
+		return fmt.Errorf("invalid sample rate: %d", sampleRate)
+	}
+
+	channelCount, err := strconv.ParseInt(tmp[1], 10, 64)
+	if err != nil {
+		return err
+	}
+	if channelCount != 2 {
+		return fmt.Errorf("invalid channel count: %d", channelCount)
+	}
+
+	for key, val := range fmtp {
+		if key == "sprop-stereo" {
+			t.IsStereo = (val == "1")
+		}
+	}
+
+	return nil
+}
+
+// Marshal implements Format.
+func (t *Opus) Marshal() (string, map[string]string) {
+	fmtp := map[string]string{
+		"sprop-stereo": func() string {
+			if t.IsStereo {
+				return "1"
+			}
+			return "0"
+		}(),
+	}
+
+	// RFC7587: The RTP clock rate in "a=rtpmap" MUST be 48000, and the
+	// number of channels MUST be 2.
+	return "opus/48000/2", fmtp
+}
+
+// PTSEqualsDTS implements Format.
+func (t *Opus) PTSEqualsDTS(*rtp.Packet) bool {
+	return true
+}
+
+// CreateDecoder creates a decoder able to decode the content of the format.
+func (t *Opus) CreateDecoder() *rtpsimpleaudio.Decoder {
+	d := &rtpsimpleaudio.Decoder{
+		SampleRate: 48000,
+	}
+	d.Init()
+	return d
+}
+
+// CreateEncoder creates an encoder able to encode the content of the format.
+func (t *Opus) CreateEncoder() *rtpsimpleaudio.Encoder {
+	e := &rtpsimpleaudio.Encoder{
+		PayloadType: t.PayloadTyp,
+		SampleRate:  48000,
+	}
+	e.Init()
+	return e
+}