WebCameraController.cs

using UnityEngine;
using System.Collections;

public class WebCameraController : MonoBehaviour
{
    public int Width = 1280;
    public int Height = 720;
    public int FPS = 30;
    public int camIndex = 0;

    void Start()
    {
        WebCamDevice[] devices = WebCamTexture.devices;
        if (devices != null && devices.Length > camIndex)
        {
            // display all cameras
            for (var i = 0; i < devices.Length; i++)
            {
                Debug.Log(devices[i].name);
            }

            WebCamTexture webcamTexture = new WebCamTexture(devices[camIndex].name, Width, Height, FPS);
            GetComponent<Renderer>().material.mainTexture = webcamTexture;
            webcamTexture.Play();
        }
        else
        {
            Debug.Log("bad index:" + camIndex);
        }
    }
}