Win10 Chrome中运行的Cast Receiver无法接收安卓YouTube投屏？

我正在遵循《Google Cast Sample Application Documentation》开发Cast Receiver默认接收器应用（未注册App ID，因此未使用个性化或自定义接收器，先以默认接收器验证效果），并将其托管在Firebase平台以实现HTTPS访问。在Chrome中打开接收器后，控制台持续输出以下重复日志：

[  0.001s] [cast.receiver.IpcChannel] Opening net websocket 
cast_receiver_framework.js:742 Lit is in dev mode. Not recommended for production! See https://lit.dev/msg/dev-mode for more information.
ao @ cast_receiver_framework.js:742
cast_receiver_framework.js:837 CAST SDK CAF Version: 3.0.0105
cast_receiver_framework.js:121  [  0.042s] [goog.net.WebSocket] Opening the WebSocket on ws://localhost:8008/v2/ipc 
media_player.js:120 CAST SDK MPL Version: 1.0.0.114
cast_receiver_framework.js:577 WebSocket connection to 'ws://localhost:8008/v2/ipc' failed: 
_.h.open @ cast_receiver_framework.js:577
cast_receiver_framework.js:121  [  2.385s] [goog.net.WebSocket] An error occurred: undefined 
vh @ cast_receiver_framework.js:121
uh.A @ cast_receiver_framework.js:614
(anonymous) @ cast_receiver_framework.js:48
jd @ cast_receiver_framework.js:48
qd @ cast_receiver_framework.js:50
_.D @ cast_receiver_framework.js:50
_.h.mm @ cast_receiver_framework.js:580
cast_receiver_framework.js:121  [  2.388s] [goog.net.WebSocket] The WebSocket on ws://localhost:8008/v2/ipc closed. 
cast_receiver_framework.js:121  [  2.389s] [goog.net.WebSocket] The WebSocket disconnected unexpectedly: undefined 
vh @ cast_receiver_framework.js:121
uh.A @ cast_receiver_framework.js:614
(anonymous) @ cast_receiver_framework.js:48
jd @ cast_receiver_framework.js:48
qd @ cast_receiver_framework.js:50
_.D @ cast_receiver_framework.js:50
_.h.Ht @ cast_receiver_framework.js:579
cast_receiver_framework.js:121  [  2.389s] [goog.net.WebSocket] Seconds until next reconnect attempt: 1 
cast_receiver_framework.js:121  [  3.394s] [goog.net.WebSocket] Opening the WebSocket on ws://localhost:8008/v2/ipc 
cast_receiver_framework.js:577 WebSocket connection to 'ws://localhost:8008/v2/ipc' failed: 
_.h.open @ cast_receiver_framework.js:577

我不确定这是否是安卓端YouTube无法搜索到投屏设备的原因。此外，我也疑惑：是否安卓或iOS设备无法投屏到Win10 Chrome中运行的Cast Receiver，仅能投屏到Google TV设备？

关于WebSocket连接失败的问题 #

• 控制台出现的WebSocket连接失败日志，是因为Cast Receiver框架默认尝试连接本地localhost:8008的IPC服务，但该服务仅存在于Google Cast硬件设备（如Google TV、Chromecast）或Chrome的Cast Receiver本地调试环境（比如用cast-receiver-cli启动的调试服务）中。直接在Chrome浏览器打开托管在Firebase的接收器页面时，本地没有该服务，所以会反复重试连接，这属于正常调试日志，不会直接导致投屏设备无法被发现，但会干扰控制台输出。
• 该日志不是安卓端YouTube搜不到投屏设备的直接原因，设备无法被发现大概率是接收器配置或网络环境的问题。

关于跨设备投屏到Chrome运行的Cast Receiver的问题 #

• 安卓/iOS设备可以投屏到Win10 Chrome中运行的Cast Receiver，但需满足以下前提：
  1. 所有设备处于同一局域网，且网络未开启局域网隔离、防火墙未拦截Cast相关端口。
  2. 需在Chrome中启用Cast Receiver调试模式：在地址栏输入chrome://flags/#media-router-cast-receiver，将选项设为Enabled，重启Chrome后，Chrome才能作为可被发现的Cast接收器。
  3. YouTube这类官方应用默认只会搜索认证过的Cast硬件设备，若要投屏到自定义/默认接收器，需在发送端应用开启调试模式，或使用Google Cast SDK提供的测试应用进行投屏测试。
• 若仅为验证默认接收器效果，更推荐使用官方的cast-receiver-cli工具在本地启动接收器，既能避免WebSocket连接错误，也更容易被测试设备发现。

内容的提问来源于stack exchange，提问作者Fly Felix