javascript – Error while toggling camera during WebRTC peer-to-peer connection: DOMException: Could not start video source

I am encountering an issue while attempting to toggle the camera during a peer-to-peer WebRTC connection. The application is built to allow users to switch between available cameras; however, upon attempting to do so, an error is thrown, specifically: “DOMException: Could not start video source”.

Here’s a snippet of the code where the error occurs:

 const handleToggleCamera = async () => {
    if (userStream) {
      try {
        const devices = await navigator.mediaDevices.enumerateDevices();
        const videoDevices = devices.filter(
          (device) => device.kind === "videoinput"
        );

        // Check if there are multiple video devices available
        if (videoDevices.length > 1) {
          // Stop the existing stream
          userStream.getTracks().forEach((track) => track.stop());

          // Get the index of the current camera track
          const currentCameraIndex = videoDevices.findIndex(
            (device) => device.label === userStream.getVideoTracks()[0].label
          );

          // Calculate the index of the next camera
          const nextCameraIndex =
            (currentCameraIndex + 1) % videoDevices.length;

          // Get senders and replace the track
          const senders = peer.peer.getSenders();
          senders.forEach((sender) => {
            peer.peer.removeTrack(sender);
          });

          // Create new options for obtaining the new stream
          const options = {
            audio: true,
            video: {
              deviceId: { exact: videoDevices[nextCameraIndex].deviceId },
            },
          };

          // Obtain the new stream
          const nextStream = await navigator.mediaDevices.getUserMedia(options);

          // Apply constraints directly to the video track
          const videoTrack = nextStream.getVideoTracks()[0];
          await videoTrack.applyConstraints({
            width: { ideal: 1280 },
            height: { ideal: 720 },
          });

          // Update the local state with the new stream
          setMyStream(null); // Set to null to ensure all tracks are removed
          setMyStream(nextStream);

          // Add the new track to the peer connection
          nextStream.getTracks().forEach((track) => {
            peer.peer.addTrack(track, nextStream);
          });

          handleNegoNeeded();
        } else {
          console.error("Device does not support switching cameras.");
          // Show error message using toast or any other UI component
        }
      } catch (error) {
        console.error("Error switching camera:", error);
        console.error("Failed constraints:", error.constraints); // Log the failed constraints
      }
    }
  };

It seems that the error occurs when attempting to obtain the new stream with the updated camera. I have tried several approaches, including stopping the existing stream before obtaining the new one, but the issue persists.

I would appreciate any insights or suggestions on how to resolve this error and successfully toggle the camera during a WebRTC peer-to-peer connection. Thank you in advance for your help!

I attempted to toggle between available cameras during a WebRTC peer-to-peer connection by implementing a function handleToggleCamera() in my application. Within this function, I enumerated the available devices using navigator.mediaDevices.enumerateDevices(), filtered out video input devices, and stopped the existing stream using userStream.getTracks().forEach((track) => track.stop()). Then, I obtained the new stream with the next camera and updated it accordingly.

Expected Outcome:
I expected that upon calling handleToggleCamera(), the application would successfully switch the camera source to the next available camera without encountering any errors. The new camera stream would replace the existing one, and the peer-to-peer connection would continue seamlessly with the updated stream.

Actual Result:
Instead, upon calling handleToggleCamera(), the application threw a DOMException with the message “Could not start video source”. This error halted the camera switching process and disrupted the peer-to-peer connection. Despite trying different approaches, including ensuring the proper stopping of the existing stream before obtaining the new one, the error persisted, preventing the successful toggling of the camera.

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