install go2rtc on bob

installs_on_host/go2rtc/pkg/pcm/handlers.go

@@ -0,0 +1,109 @@
+package pcm
+
+import (
+	"sync"
+	"time"
+
+	"github.com/AlexxIT/go2rtc/pkg/core"
+	"github.com/pion/rtp"
+)
+
+// RepackG711 - Repack G.711 PCMA/PCMU into frames of size 1024
+//  1. Fixes WebRTC audio quality issue (monotonic timestamp)
+//  2. Fixes Reolink Doorbell backchannel issue (zero timestamp)
+//     https://github.com/AlexxIT/go2rtc/issues/331
+func RepackG711(zeroTS bool, handler core.HandlerFunc) core.HandlerFunc {
+	const PacketSize = 1024
+
+	var buf []byte
+	var seq uint16
+	var ts uint32
+
+	// fix https://github.com/AlexxIT/go2rtc/issues/432
+	var mu sync.Mutex
+
+	return func(packet *rtp.Packet) {
+		mu.Lock()
+
+		buf = append(buf, packet.Payload...)
+		if len(buf) < PacketSize {
+			mu.Unlock()
+			return
+		}
+
+		pkt := &rtp.Packet{
+			Header: rtp.Header{
+				Version:        2,
+				Marker:         true,               // should be true
+				PayloadType:    packet.PayloadType, // will be owerwriten
+				SequenceNumber: seq,
+				SSRC:           packet.SSRC,
+			},
+			Payload: buf[:PacketSize],
+		}
+
+		seq++
+
+		// don't know if zero TS important for Reolink Doorbell
+		// don't have this strange devices for tests
+		if !zeroTS {
+			pkt.Timestamp = ts
+			ts += PacketSize
+		}
+
+		buf = buf[PacketSize:]
+
+		mu.Unlock()
+
+		handler(pkt)
+	}
+}
+
+// LittleToBig - convert PCM little endian to PCM big endian
+func LittleToBig(handler core.HandlerFunc) core.HandlerFunc {
+	return func(packet *rtp.Packet) {
+		clone := *packet
+		clone.Payload = FlipEndian(packet.Payload)
+		handler(&clone)
+	}
+}
+
+func TranscodeHandler(dst, src *core.Codec, handler core.HandlerFunc) core.HandlerFunc {
+	var ts uint32
+	k := float32(BytesPerFrame(dst)) / float32(BytesPerFrame(src))
+	f := Transcode(dst, src)
+
+	return func(packet *rtp.Packet) {
+		ts += uint32(k * float32(len(packet.Payload)))
+
+		clone := *packet
+		clone.Payload = f(packet.Payload)
+		clone.Timestamp = ts
+		handler(&clone)
+	}
+}
+
+func BytesPerSample(codec *core.Codec) int {
+	switch codec.Name {
+	case core.CodecPCML, core.CodecPCM:
+		return 2
+	case core.CodecPCMU, core.CodecPCMA:
+		return 1
+	}
+	return 0
+}
+
+func BytesPerFrame(codec *core.Codec) int {
+	if codec.Channels <= 1 {
+		return BytesPerSample(codec)
+	}
+	return int(codec.Channels) * BytesPerSample(codec)
+}
+
+func FramesPerDuration(codec *core.Codec, duration time.Duration) int {
+	return int(time.Duration(codec.ClockRate) * duration / time.Second)
+}
+
+func BytesPerDuration(codec *core.Codec, duration time.Duration) int {
+	return BytesPerFrame(codec) * FramesPerDuration(codec, duration)
+}