Widevine DRM - Body request payload

Question

I'm working on the integration of a player which have to play streams secured with Widevine DRM in a browser.

I've checked some well-known players :

• DashJs - https://github.com/Dash-Industry-Forum/dash.js/wiki
• ShakaPlayer - https://github.com/google/shaka-player

Fortunately, these players provide some samples of stream secured using Widevine DRM.

My question concerns the XHR executes to retrieve DRM Key. In any Widevine secured stream, I can see (in devtools) at least 2 XHR targeting the license server.

Let's take an example: https://media.axprod.net/TestVectors/v7-MultiDRM-SingleKey/Manifest_1080p.mpd

This stream is available in :

• DashJs (https://reference.dashif.org/dash.js/nightly/samples/dash-if-reference-player/index.html) : "Axinom Test Content (modern) > 1080p with PlayReady and Widevine DRM, single key"
• ShakaPlayer (https://shaka-player-demo.appspot.com/demo/) : "Axinom > Multi-DRM"

在 Chrome (65.0.3325.181) 上，当我加载流时，我可以 2 XHR（让我们省略飞行前的“OPTIONS”xhr）：

• 邮政https://drm-widevine-licensing.axtest.net/AcquireLicense
  • X-AxDRM-MessageAxinom 特有的请求标头
  • 要求Content-Length: 2
  • 请求有效负载等于\x08\x04（右键单击 XHR，然后“复制为 cURL”并将其粘贴到任何文本编辑器中）
  • 回复Content-Length: 706
• 邮政https://drm-widevine-licensing.axtest.net/AcquireLicense
  • X-AxDRM-MessageAxinom 特有的请求标头
  • 要求Content-Length: 3929
  • 具有一定数据量的请求负载
  • 回复Content-Length: 426

我不明白为什么有2个XHR？\x08\x04此外，无论选择哪种流（在 Widevine DRM 流的情况下），第一个包含两个字符的 XHR总是会发送，有具体含义吗？

Answer 1

第一个请求是 Widevine 服务证书

第二个请求是实际的许可证请求

您可以在https://www.widevine.com/product_news.html上阅读更多相关信息

参见 参考资料 部分Update - Chrome 59 and Service Certificates