install go2rtc on bob

installs_on_host/go2rtc/pkg/mjpeg/helpers.go

@@ -0,0 +1,100 @@
+package mjpeg
+
+import (
+	"bytes"
+	"image/jpeg"
+
+	"github.com/AlexxIT/go2rtc/pkg/core"
+	"github.com/AlexxIT/go2rtc/pkg/y4m"
+	"github.com/pion/rtp"
+)
+
+func FixJPEG(b []byte) []byte {
+	// skip non-JPEG
+	if len(b) < 10 || b[0] != 0xFF || b[1] != markerSOI {
+		return b
+	}
+
+	// skip JPEG without app marker
+	if b[2] == 0xFF && b[3] == markerDQT {
+		return b
+	}
+
+	switch string(b[6:10]) {
+	case "JFIF", "Exif":
+		// skip if header OK for imghdr library
+		// - https://docs.python.org/3/library/imghdr.html
+		return b
+	case "AVI1":
+		// adds DHT tables to JPEG file before SOS marker
+		// useful when you want to save a JPEG frame from an MJPEG stream
+		// - https://github.com/image-rs/jpeg-decoder/issues/76
+		// - https://github.com/pion/mediadevices/pull/493
+		// - https://bugzilla.mozilla.org/show_bug.cgi?id=963907#c18
+		return InjectDHT(b)
+	}
+
+	// reencode JPEG if it has wrong header
+	//
+	// for example, this app produce "bad" images:
+	// https://github.com/jacksonliam/mjpg-streamer
+	//
+	// and they can't be uploaded to the Telegram servers:
+	// {"ok":false,"error_code":400,"description":"Bad Request: IMAGE_PROCESS_FAILED"}
+	img, err := jpeg.Decode(bytes.NewReader(b))
+	if err != nil {
+		return b
+	}
+	buf := bytes.NewBuffer(nil)
+	if err = jpeg.Encode(buf, img, nil); err != nil {
+		return b
+	}
+	return buf.Bytes()
+}
+
+// Encoder convert YUV frame to Img.
+// Support skipping empty frames, for example if USB cam needs time to start.
+func Encoder(codec *core.Codec, skipEmpty int, handler core.HandlerFunc) core.HandlerFunc {
+	newImage := y4m.NewImage(codec.FmtpLine)
+
+	return func(packet *rtp.Packet) {
+		img := newImage(packet.Payload)
+
+		if skipEmpty != 0 && y4m.HasSameColor(img) {
+			skipEmpty--
+			return
+		}
+
+		buf := bytes.NewBuffer(nil)
+		if err := jpeg.Encode(buf, img, nil); err != nil {
+			return
+		}
+
+		clone := *packet
+		clone.Payload = buf.Bytes()
+		handler(&clone)
+	}
+}
+
+const dhtSize = 432 // known size for 4 default tables
+
+func InjectDHT(b []byte) []byte {
+	if bytes.Index(b, []byte{0xFF, markerDHT}) > 0 {
+		return b // already exist
+	}
+
+	i := bytes.Index(b, []byte{0xFF, markerSOS})
+	if i < 0 {
+		return b
+	}
+
+	dht := make([]byte, 0, dhtSize)
+	dht = MakeHuffmanHeaders(dht)
+
+	tmp := make([]byte, len(b)+dhtSize)
+	copy(tmp, b[:i])
+	copy(tmp[i:], dht)
+	copy(tmp[i+dhtSize:], b[i:])
+
+	return tmp
+}