WebGLビルドの場合は、正しいカメラ解像度が取得できないようです。すべての3840x2160 60FPSの設定になるようです。

        

            using System;
            using System.Collections;
            using System.Collections.Generic;
            using UnityEngine;
            using UnityEngine.UI;
            using System.Linq;
            using TMPro;

            namespace SyskenTLib.SimpleFunction1.Camera
            {



            public class SimpleCamera : MonoBehaviour
            {
            [SerializeField]
            private TMP_Dropdown _cameraListDropDown;

            [SerializeField] private RawImage _cameraRawImage;
            [SerializeField] private AspectRatioFitter _aspectRatioFitter;

            [SerializeField] private TextMeshProUGUI _logText;

            private WebCamTexture _currentCameraTexture;

            // Start is called before the first frame update
            void Start()
            {
            WebCamDevice[] cameraDevices = WebCamTexture.devices;

            List dropdownValueList = new List();

                    cameraDevices.ToList().ForEach(cameraDevice =>
                    {
                    TMP_Dropdown.OptionData optionData = new TMP_Dropdown.OptionData();
                    optionData.text = cameraDevice.name;

                    dropdownValueList.Add(optionData);
                    });

                    _cameraListDropDown.options = dropdownValueList;


                    _cameraListDropDown.onValueChanged.AddListener(OnSelectDropdown);
                    }

                    private void OnSelectDropdown(int selectIndex)
                    {
                    if (_currentCameraTexture)
                    {
                    _currentCameraTexture.Stop();
                    }


                    WebCamDevice cameraDevice = WebCamTexture.devices[selectIndex];


                    _currentCameraTexture = new WebCamTexture(cameraDevice.name,3840,2160,60);
                    _currentCameraTexture.Play();

                    }

                    private void Update()
                    {
                    if (_currentCameraTexture)
                    {
                    _cameraRawImage.texture = _currentCameraTexture;
                    _aspectRatioFitter.aspectRatio = 1.0f*_currentCameraTexture.width / _currentCameraTexture.height;




                    if (_logText)
                    {
                    _logText.text = ""+_currentCameraTexture.deviceName
                    +"  w:" + _currentCameraTexture.width
                    + "  h:" + _currentCameraTexture.height
                    + "  fps:" + _currentCameraTexture.requestedFPS;

                    }

                    }
                    }
                    }
                    }