mirror of https://github.com/pikvm/pikvm.git
53 lines
2.7 KiB
Markdown
53 lines
2.7 KiB
Markdown
# WebRTC
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This is a new alternative video transfer mode available for Raspberry Pi 4 users with an HDMI-CSI bridge.
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It uses H.264 encoding instead of MJPEG and provides significantly less traffic consumption.
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# How to use
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If you use an OS image built after 2021.06.10, this mode will be available to you by default.
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If you are upgrading to an older version of the OS, you will need to manually enable the WebRTC gateway:
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```
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# systemctl enable --now kvmd-janus
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```
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Then restart the Web UI and then in the **System** menu you will see the video mode switch.
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:exclamation: **If you do not see the switch, it means that either your browser does not support WebRTC, or the `kvmd-janus` service was not started.**
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# Subtleties
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The MJPEG video stream uses the same HTTP connection that you use to download the web interface.
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This means that for remote access, you just need to forward ports 80 and 443 on your router.
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In contrast, WebRTC is a completely different way of transmitting video.
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It uses a P2P connection and UDP. This reduces network load, but makes it difficult to configure
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- the server needs to know your network configuration in order to use it correctly.
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To implement this, the Pi-KVM checks which of the network interfaces is used for the default gateway,
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and also tries to find out your external address using the Google [STUN](https://en.wikipedia.org/wiki/STUN) server.
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This is necessary when using [Tailscale](tailscale.md) or so that you can connect to your Pi-KVM from the external Internet,
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since simply forwarding ports 80 and 443 for WebRTC is not enough - it requires a direct connection.
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If you don't like using Google (it was chosen as the default for reliability reasons) for this purpose,
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you can choose [any other STUN server](https://www.voip-info.org/stun/) at your discretion, or start your own.
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Use `/etc/kvmd/override.yaml` to this:
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```yaml
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janus:
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stun:
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host: stun.stunprotocol.org
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port: 3478
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```
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And restart `systemctl restart kvmd-janus`.
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# Custom Janus config
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❗**Custom config is not working right now**
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[Janus](https://janus.conf.meetecho.com) is a WebRTC gateway that is used to transmit the [uStreamer](https://github.com/pikvm/ustreamer) video.
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KVMD-Janus is a wrapper around it, configuring and monitoring changes in the network configuration. This is suitable for most users.
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However, if your Pi-KVM is not connected to the Internet and/or you want to use a custom Janus configuration,
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then you should use the `kvmd-janus-static` service instead. You should first change the Janus configuration yourself.
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You can find it in `/etc/kvmd/janus/janus.jcfg`.
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```
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# systemctl disable --now kvmd-janus
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...
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# systemctl enable --now kvmd-janus-static
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```
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