AlexxIT/go2rtc · error

ErrCantGetTrack

ErrCantGetTrack

Error message

can't get track

What it means

core.ErrCantGetTrack ("can't get track", pkg/core/track.go:10) is the sentinel returned when a media producer cannot supply a Receiver for the requested Media/Codec combination. Several backends (e.g. pkg/alsa/playback_linux.go GetTrack, pkg/doorbird/backchannel.go GetTrack) unconditionally return it because they simply do not support producing a track. It signals an unsupported/unavailable media track, not a transport failure.

Solutions

1. Check support with errors.Is(err, core.ErrCantGetTrack) and skip/disable that track in your application instead of retrying.
2. Pick a backend/device that supports the requested direction (e.g. use a speaker-capable integration for backchannel).
3. Request only tracks the device actually produces (inspect Media/Codec from GetMedias first).
4. Implement the track in the backend if you own the driver code; the stub returns nil, ErrCantGetTrack by design.

Example fix

// before
track, err := producer.GetTrack(media, codec)
if err != nil {
    return err // aborts whole pipeline on unsupported backchannel
}
// after
track, err := producer.GetTrack(media, codec)
if errors.Is(err, core.ErrCantGetTrack) {
    return nil // no track available; continue without it
}

// check the device offers the media before asking for a track
if len(media.GetVideo()) == 0 && isVideoRequest {
    return nil // nothing to request
}

func trackAvailable(err error) bool {
    return !errors.Is(err, core.ErrCantGetTrack)
}

track, err := producer.GetTrack(media, codec)
if errors.Is(err, core.ErrCantGetTrack) {
    log.Info("track not supported by backend; continuing without it")
    return nil
}

When it happens

Trigger: Calling GetTrack(media, codec) on a backend that has no track for the given media/codec — including ALSA playback and Doorbird backchannel, which always return ErrCantGetTrack.

Common situations: Requesting two-way audio (backchannel) from a Doorbird camera whose integration doesn't support it; requesting a track from a sink that only consumes (ALSA playback); asking for a codec the device doesn't emit; consumer code not checking for the sentinel and treating it as transient.

Understand the failure class

Background: 'Could not be found', 'does not exist', 'not found in database': the resource-not-found family when an ID, slug, key, or URI lookup comes back empty — this error's family across 20 libraries.

Related errors

• ErrRead
• probe reader overflow
• dvrip: can't probe medias
• kasa: unsupported type:
• webrtc: can't get track

AI-assisted analysis of AlexxIT/go2rtc@c245815e75 (2026-09-07). Data as JSON: /api/errors/cda2fe99a053e84c. Report an issue: GitHub.

Appendix: source

Thrown at pkg/core/track.go:10

package core

import (
	"encoding/json"
	"errors"

	"github.com/pion/rtp"
)

var ErrCantGetTrack = errors.New("can't get track")

type Receiver struct {
	Node

	// Deprecated: should be removed
	Media *Media `json:"-"`
	// Deprecated: should be removed
	ID byte `json:"-"` // Channel for RTSP, PayloadType for MPEG-TS

	Bytes   int `json:"bytes,omitempty"`
	Packets int `json:"packets,omitempty"`
}

func NewReceiver(media *Media, codec *Codec) *Receiver {
	r := &Receiver{
		Node:  Node{id: NewID(), Codec: codec},
		Media: media,
	}

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