add MP4A-LATM format (#237)

pkg/formats/mpeg4_video_es.go

@@ -0,0 +1,80 @@
+package formats
+
+import (
+	"encoding/hex"
+	"fmt"
+	"strconv"
+	"strings"
+
+	"github.com/pion/rtp"
+)
+
+// MPEG4Video is an alias for MPEG4VideoES.
+type MPEG4Video = MPEG4VideoES
+
+// MPEG4VideoES is a RTP format that uses the video codec defined in MPEG-4 part 2.
+// Specification: https://datatracker.ietf.org/doc/html/rfc6416#section-7.1
+type MPEG4VideoES struct {
+	PayloadTyp     uint8
+	ProfileLevelID int
+	Config         []byte
+}
+
+// String implements Format.
+func (f *MPEG4VideoES) String() string {
+	return "MPEG4-video-es"
+}
+
+// ClockRate implements Format.
+func (f *MPEG4VideoES) ClockRate() int {
+	return 90000
+}
+
+// PayloadType implements Format.
+func (f *MPEG4VideoES) PayloadType() uint8 {
+	return f.PayloadTyp
+}
+
+func (f *MPEG4VideoES) unmarshal(
+	payloadType uint8, clock string, codec string,
+	rtpmap string, fmtp map[string]string,
+) error {
+	f.PayloadTyp = payloadType
+	f.ProfileLevelID = 1 // default value defined by specification
+
+	for key, val := range fmtp {
+		switch key {
+		case "profile-level-id":
+			tmp, err := strconv.ParseInt(val, 10, 64)
+			if err != nil {
+				return fmt.Errorf("invalid profile-level-id: %v", val)
+			}
+
+			f.ProfileLevelID = int(tmp)
+
+		case "config":
+			var err error
+			f.Config, err = hex.DecodeString(val)
+			if err != nil {
+				return fmt.Errorf("invalid config: %v", val)
+			}
+		}
+	}
+
+	return nil
+}
+
+// Marshal implements Format.
+func (f *MPEG4VideoES) Marshal() (string, map[string]string) {
+	fmtp := map[string]string{
+		"profile-level-id": strconv.FormatInt(int64(f.ProfileLevelID), 10),
+		"config":           strings.ToUpper(hex.EncodeToString(f.Config)),
+	}
+
+	return "MP4V-ES/90000", fmtp
+}
+
+// PTSEqualsDTS implements Format.
+func (f *MPEG4VideoES) PTSEqualsDTS(*rtp.Packet) bool {
+	return true
+}