AlexxIT/go2rtc · error

eseecloud: wrong start byte

Error message

eseecloud: wrong start byte

What it means

eseecloud.readPacket (pkg/eseecloud/eseecloud.go:163) reads a packet header via io.ReadFull and requires the first byte to be '$'. If b[0] != '$' it returns "eseecloud: wrong start byte", meaning the TCP stream is no longer aligned with the EseeCloud packet framing or the peer is not speaking the EseeCloud protocol.

Solutions

1. Reconnect (restart Start/probe): once the stream is misaligned, the framing cannot recover in place.
2. Verify the host and port actually serve the EseeCloud protocol (captured packets should start with '$').
3. Rule out middleboxes or relays replacing the payload (HTML error pages, captive portals).
4. Check device firmware compatibility; a protocol change can alter the framing.
5. Capture traffic to inspect the exact bytes arriving when the error occurs.

Example fix

// before: keep reading after desync
for {
    pkt, err := p.readPacket() // wrong start byte repeats
}
// after: rebuild the connection
if err != nil {
    p.Close()
    err = p.Start(ctx) // fresh TCP session, resynced framing
}

pkt, err := p.readPacket()
if err != nil && strings.HasSuffix(err.Error(), "wrong start byte") {
    p.Close()
    err = p.Start(ctx) // resync requires a new session
}

When it happens

Trigger: readPacket, invoked by Start and probe, when the first byte of a packet is not '$' — desynced stream after a partial read, garbage injected mid-session, or a non-EseeCloud service on the port.

Common situations: Device or cloud relay resetting the connection and sending an error page/HTML instead of framed packets; wrong host/port (connecting to camera HTTP UI instead of the EseeCloud stream port); leftover partial packet from a previous error desynchronizing the reader.

Understand the failure class

Background: "invalid response format", "malformed payload", "missing data field": when an API returns 200 but the response shape is wrong — this error's family across 23 libraries.

Related errors

• wrong start byte
• read error
• flv: wrong header
• wrong response:
• wrong auth response

AI-assisted analysis of AlexxIT/go2rtc@c245815e75 (2026-09-07). Data as JSON: /api/errors/ef4cb5d054b2e80c. Report an issue: GitHub.

Appendix: source

Thrown at pkg/eseecloud/eseecloud.go:163

						Timestamp:      uint32(uint64(pkt.Timestamp) * 8000 / 1000000),
					},
					Payload: pkt.Payload,
				}
			}
			recv.WriteRTP(pkt)
		}
	}
}

func (p *Producer) readPacket() (*core.Packet, error) {
	b := make([]byte, 8)

	if _, err := io.ReadFull(p.rd, b); err != nil {
		return nil, err
	}

	if b[0] != '$' {
		return nil, errors.New("eseecloud: wrong start byte")
	}

	size := binary.BigEndian.Uint32(b[4:])
	b = make([]byte, size)
	if _, err := io.ReadFull(p.rd, b); err != nil {
		return nil, err
	}

	pkt := &core.Packet{}
	if err := pkt.Unmarshal(b); err != nil {
		return nil, err
	}

	p.Recv += int(size)

	return pkt, nil
}

View on GitHub (pinned to c245815e75)