Troubleshooting: No Signal Between Encoder and Decoder

Overview

If a KanexPro AV over IP decoder is showing no signal, a black screen, or a frozen image, work through the steps below in order. Most issues are caused by network misconfiguration, IGMP settings, or IP addressing conflicts.

Step 1 — Verify Physical Connections

• Confirm the encoder HDMI input is connected to an active source and the source is outputting video.
• Confirm the decoder HDMI output is connected to a powered-on display set to the correct input.
• Confirm both encoder and decoder are connected to the same managed switch via Ethernet.
• Check that all Ethernet cables are CAT5e or better and that link LEDs are lit on both the device and the switch port.

Step 2 — Verify Network Switch Settings

This is the most common cause of no-signal issues on first install.

• IGMP snooping: Must be enabled globally and on the AV VLAN. Without it, multicast video floods all ports and devices cannot receive streams reliably.
• IGMP querier: Must be enabled on the AV VLAN if no multicast router is present.
• Jumbo frames: For JPEG2000 and SDVoE, MTU must be set to 9000 on all AV ports. A mismatch causes packet fragmentation and dropped video.
• Flow control: Must be disabled on all AV ports.
• Port speed: JPEG2000/H.265 require 1G. SDVoE requires 10G. Verify port speed matches the device.

Step 3 — Verify IP Addressing

• Both encoder and decoder must be on the same IP subnet.
• Check for IP address conflicts — two devices sharing the same IP will cause intermittent or no signal.
• If using DHCP, verify the DHCP server is reachable and has available addresses.
• Access each device’s web GUI by entering its IP address in a browser. If unreachable, the device may have a conflicting or incorrect IP.

Step 4 — Verify Routing Assignment

• If using an IP controller, open the web GUI and confirm the encoder is routed to the correct decoder.
• An unassigned decoder will show no signal even if the network is correctly configured.
• Try re-routing the encoder to the decoder manually in the controller web GUI.

Step 5 — Check HDCP

• If the source is HDCP-protected, the display must support HDCP. An HDCP handshake failure will result in no signal or a black screen with a brief flash.
• Test with a non-HDCP source (e.g., a laptop with HDCP disabled or a signal generator) to isolate whether HDCP is the cause.

Step 6 — Reboot Sequence

1. Power off the decoder.
2. Power off the encoder.
3. Wait 10 seconds.
4. Power on the encoder and wait 30 seconds for it to fully initialize.
5. Power on the decoder.
6. Wait 30 seconds for auto-discovery and stream establishment.

Step 7 — Factory Reset

If the above steps do not resolve the issue, perform a factory reset on both the encoder and decoder using the reset button on the rear panel. After reset, reconfigure IP settings and routing via the web GUI.

Still No Signal?

Contact KanexPro technical support at support@kanexpro.com or call 888.975.1368 with the following information:

• SKU of encoder and decoder
• Switch make and model
• IGMP and MTU settings
• IP addresses of both devices
• Screenshot of routing matrix from controller (if applicable)

Related Products

• AVO-IPJP2K — JPEG2000 Encoder/Decoder
• AVO-IP265-4K — H.265 4K Encoder/Decoder
• AVO-IPSDV-4K — SDVoE Encoder/Decoder

Related Articles

• Network Setup for AV over IP
• Getting Started with AV over IP
• JPEG2000 Product Guide
• IP Controller Setup and REST API Reference