AlexxIT/go2rtc · error

add track not supported for snapshot

Error message

add track not supported for snapshot

What it means

Client.AddTrack only supports adding media tracks to a WebRTC (live-stream) session via the underlying production client. When the client was created for a snapshot session, no WebRTC track machinery exists, so the call fails with this sentinel error. It signals an API misuse: tracks are meaningless for a single still image.

Solutions

1. Create a live-stream (WebRTC) client/session instead of a snapshot client before calling AddTrack.
2. If you only need a still image, drop the AddTrack call and use the snapshot API directly.
3. Check the session mode before adding tracks and branch your code accordingly.

Example fix

// before
snapClient := ring.NewSnapshotClient(...)
snapClient.AddTrack(media, codec, track) // fails
// after
liveClient, _ := ring.Dial(ctx, cameraID, token) // WebRTC/live session
liveClient.AddTrack(media, codec, track)

if isSnapshotSession(client) {
    return errors.New("AddTrack requires a live WebRTC session, not a snapshot client")
}

if err := client.AddTrack(media, codec, track); err != nil {
    if err.Error() == "add track not supported for snapshot" {
        // fall back to snapshot capture instead of live streaming
    }
    return err
}

When it happens

Trigger: Calling AddTrack on a ring Client that was created in snapshot mode (e.g. via a snapshot/live-switch configuration) instead of a live WebRTC session.

Common situations: Reusing one Client for both snapshot capture and live streaming; code paths that unconditionally call AddTrack without checking whether the session is a snapshot; an upstream pipeline that always attaches audio/video tracks.

Understand the failure class

Background: UnsupportedOperationException and "is not supported" errors: when a library deliberately refuses a call — this error's family across 30 libraries.

Related errors

• unsupported url:
• webrtc:
• wrong answer:
• webrtc:
• wyse: wrong result:

AI-assisted analysis of AlexxIT/go2rtc@c245815e75 (2026-09-07). Data as JSON: /api/errors/ceb39342d2d41ef8. Report an issue: GitHub.

Appendix: source

Thrown at pkg/ring/client.go:328

}

func (c *Client) GetTrack(media *core.Media, codec *core.Codec) (*core.Receiver, error) {
	return c.prod.GetTrack(media, codec)
}

func (c *Client) AddTrack(media *core.Media, codec *core.Codec, track *core.Receiver) error {
	if webrtcProd, ok := c.prod.(*webrtc.Conn); ok {
		if media.Kind == core.KindAudio {
			// Enable speaker
			speakerPayload := map[string]interface{}{
				"stealth_mode": false,
			}
			_ = c.wsClient.sendSessionMessage("camera_options", speakerPayload)
		}
		return webrtcProd.AddTrack(media, codec, track)
	}

	return fmt.Errorf("add track not supported for snapshot")
}

func (c *Client) Start() error {
	return c.prod.Start()
}

func (c *Client) Stop() error {
	if c.closed {
		return nil
	}

	c.closed = true

	if c.prod != nil {
		_ = c.prod.Stop()
	}

	if c.wsClient != nil {

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