add MP4A-LATM format (#237)

pkg/formats/mpeg4_audio_generic.go

@@ -0,0 +1,159 @@
+package formats
+
+import (
+	"encoding/hex"
+	"fmt"
+	"strconv"
+
+	"github.com/pion/rtp"
+
+	"github.com/bluenviron/gortsplib/v3/pkg/formats/rtpmpeg4audio"
+	"github.com/bluenviron/mediacommon/pkg/codecs/mpeg4audio"
+)
+
+// MPEG4Audio is an alias for MPEG4AudioGeneric.
+type MPEG4Audio = MPEG4AudioGeneric
+
+// MPEG4AudioGeneric is a RTP format that uses a MPEG-4 audio codec.
+// Specification: https://datatracker.ietf.org/doc/html/rfc3640
+type MPEG4AudioGeneric struct {
+	PayloadTyp       uint8
+	Config           *mpeg4audio.Config
+	SizeLength       int
+	IndexLength      int
+	IndexDeltaLength int
+}
+
+// String implements Format.
+func (f *MPEG4AudioGeneric) String() string {
+	return "MPEG4-audio-gen"
+}
+
+// ClockRate implements Format.
+func (f *MPEG4AudioGeneric) ClockRate() int {
+	return f.Config.SampleRate
+}
+
+// PayloadType implements Format.
+func (f *MPEG4AudioGeneric) PayloadType() uint8 {
+	return f.PayloadTyp
+}
+
+func (f *MPEG4AudioGeneric) unmarshal(
+	payloadType uint8, clock string, codec string,
+	rtpmap string, fmtp map[string]string,
+) error {
+	f.PayloadTyp = payloadType
+
+	for key, val := range fmtp {
+		switch key {
+		case "config":
+			enc, err := hex.DecodeString(val)
+			if err != nil {
+				return fmt.Errorf("invalid AAC config: %v", val)
+			}
+
+			f.Config = &mpeg4audio.Config{}
+			err = f.Config.Unmarshal(enc)
+			if err != nil {
+				return fmt.Errorf("invalid AAC config: %v", val)
+			}
+
+		case "sizelength":
+			n, err := strconv.ParseUint(val, 10, 64)
+			if err != nil {
+				return fmt.Errorf("invalid AAC SizeLength: %v", val)
+			}
+			f.SizeLength = int(n)
+
+		case "indexlength":
+			n, err := strconv.ParseUint(val, 10, 64)
+			if err != nil {
+				return fmt.Errorf("invalid AAC IndexLength: %v", val)
+			}
+			f.IndexLength = int(n)
+
+		case "indexdeltalength":
+			n, err := strconv.ParseUint(val, 10, 64)
+			if err != nil {
+				return fmt.Errorf("invalid AAC IndexDeltaLength: %v", val)
+			}
+			f.IndexDeltaLength = int(n)
+		}
+	}
+
+	if f.Config == nil {
+		return fmt.Errorf("config is missing")
+	}
+
+	if f.SizeLength == 0 {
+		return fmt.Errorf("sizelength is missing")
+	}
+
+	return nil
+}
+
+// Marshal implements Format.
+func (f *MPEG4AudioGeneric) Marshal() (string, map[string]string) {
+	enc, err := f.Config.Marshal()
+	if err != nil {
+		return "", nil
+	}
+
+	sampleRate := f.Config.SampleRate
+	if f.Config.ExtensionSampleRate != 0 {
+		sampleRate = f.Config.ExtensionSampleRate
+	}
+
+	fmtp := map[string]string{
+		"profile-level-id": "1",
+		"mode":             "AAC-hbr",
+	}
+
+	if f.SizeLength > 0 {
+		fmtp["sizelength"] = strconv.FormatInt(int64(f.SizeLength), 10)
+	}
+
+	if f.IndexLength > 0 {
+		fmtp["indexlength"] = strconv.FormatInt(int64(f.IndexLength), 10)
+	}
+
+	if f.IndexDeltaLength > 0 {
+		fmtp["indexdeltalength"] = strconv.FormatInt(int64(f.IndexDeltaLength), 10)
+	}
+
+	fmtp["config"] = hex.EncodeToString(enc)
+
+	return "mpeg4-generic/" + strconv.FormatInt(int64(sampleRate), 10) +
+		"/" + strconv.FormatInt(int64(f.Config.ChannelCount), 10), fmtp
+}
+
+// PTSEqualsDTS implements Format.
+func (f *MPEG4AudioGeneric) PTSEqualsDTS(*rtp.Packet) bool {
+	return true
+}
+
+// CreateDecoder creates a decoder able to decode the content of the format.
+func (f *MPEG4AudioGeneric) CreateDecoder() *rtpmpeg4audio.Decoder {
+	d := &rtpmpeg4audio.Decoder{
+		SampleRate:       f.Config.SampleRate,
+		SizeLength:       f.SizeLength,
+		IndexLength:      f.IndexLength,
+		IndexDeltaLength: f.IndexDeltaLength,
+	}
+	d.Init()
+	return d
+}
+
+// CreateEncoder creates an encoder able to encode the content of the format.
+func (f *MPEG4AudioGeneric) CreateEncoder() *rtpmpeg4audio.Encoder {
+	e := &rtpmpeg4audio.Encoder{
+		PayloadType:      f.PayloadTyp,
+		SampleRate:       f.Config.SampleRate,
+		SizeLength:       f.SizeLength,
+		IndexLength:      f.IndexLength,
+		IndexDeltaLength: f.IndexDeltaLength,
+	}
+	e.Init()
+	return e
+}