AV1 samplebuilder support (WIP)

codecs/av1_packet.go

@@ -134,6 +134,8 @@
 	// Each AV1 RTP Packet is a collection of OBU Elements. Each OBU Element may be a full OBU, or just a fragment of one.
 	// AV1Frame provides the tools to construct a collection of OBUs from a collection of OBU Elements
 	OBUElements [][]byte
+
+	videoDepacketizer
 }
 
 // Unmarshal parses the passed byte slice and stores the result in the AV1Packet this method is called upon
@@ -186,3 +188,48 @@
 
 	return payload[1:], nil
 }
+
+func (p *AV1Packet) IsPartitionHead(payload []byte) bool {
+	// at this point, p.Unmarshal may not have been called yet.  Check
+	// manually for Z == 0 & N == 1.
+	return len(payload) > 0 && (payload[0] & 0x88) != 0x08
+}
+
+// AppendToSample appends the contents of the packet to a sample.  It
+// reconstructs the size of the last OBU if required.
+func (p *AV1Packet) AppendToSample(sample, payload []byte) []byte {
+	if len(payload) < 1 {
+		return sample
+	}
+
+	switch p.W {
+	case 0:
+		sample = append(sample, payload...)
+	case 1:
+		sample = append(sample, obu.WriteToLeb128(uint(len(payload)))...)
+		sample = append(sample, payload...)
+	case 2:
+		l1, ll1, err := obu.ReadLeb128(payload)
+		if err != nil {
+			return sample
+		}
+		sample = append(sample, payload[:l1+ll1]...)
+		l2 := uint(len(payload)) - (l1 + ll1)
+		sample = append(sample, obu.WriteToLeb128(l2)...)
+		sample = append(sample, payload[l1+ll1:]...)
+	case 3:
+		l1, ll1, err := obu.ReadLeb128(payload)
+		if err != nil {
+			return sample
+		}
+		l2, ll2, err := obu.ReadLeb128(payload[l1+ll1:])
+		if err != nil {
+			return sample
+		}
+		l3 := uint(len(payload)) - (l1 + ll1 + l2 + ll2)
+		sample = append(sample, payload[:l1+ll1+l2+ll2]...)
+		sample = append(sample, obu.WriteToLeb128(l3)...)
+		sample = append(sample, payload[l1+ll1+l2+ll2:]...)
+	}
+	return sample
+}