Safari Fairplay MediaKeys Polyfill

[sanbornhilland]

In issue #279 it was mentioned that "The status of Fairplay through EME is unknown at this time." Can you elaborate on what you mean by this? We have some apple sample code that shows Fairplay playback in Safari. However trying to play the same content through Shaka with an HLS Parser plugin is not going so smoothly. I'm not sure the MediaKeys polyfill is working correctly on Safari. Have you tested in Safari?

I can get more detailed logs and specific failings in the next few days but I wanted to initially enquire about the compatibility of the MediaKeys polyfill and the Safari (9.1) EME implementation.

[joeyparrish]

What I meant by that comment is that we have never seen any Fairplay-compatible DASH content we could try in Shaka, nor any EME-based Fairplay demos using HLS. So we can only assume Apple's EME works. Can you share a link to something of that sort?

A quick check shows that Safari 9's EME is the webkit-prefixed v0.1b API. The polyfill for that was originally developed against Chrome, but Chrome has long-since implemented the unprefixed working-draft EME API. If we need to modify the polyfill to better support Safari, I have no problems with that. Safari is, at the moment, the only known consumer of it.

[sanbornhilland]

We have a server issue to resolve but then I should be able to provide you with a working Safari sample with HLS Fairplay content.

[sanbornhilland]

I'm still working on getting you some HLS + Fairplay samples to give you. But there is sample client code from apple here: https://developer.apple.com/streaming/fps/ if you download the FairPlay Streaming Server SDK. If you haven't looked at this it would be useful for comparing to the v01b polyfill.

For instance, for FPS on Safari the init data is formed by concatenating the initData from the needkey event with a contentId and an Apple App Cert. I believe this is different from Chrome and other browsers that just require the init data? It looks to me like currently Shaka and the MediaKeys polyfill assumes the needkey event.initData is sufficient.

After that it looks like there are some other differences. The concatenated init data is passed in the createSession call and then there is no generateRequest call at all. This also appears to be different than how Shaka is handling it where the createSession call does not take any arguments and there is a generateRequest call that takes initData.

It appears to me that the flow on Safari is a bit different than on Chrome. I have tested that Apple sample code with HLS + Fairplay content and it does work in Safari.

I'm also having the following issue in Safari: In shaka.polyfill.PatchedMediaKeys.v01b.MediaKeys.prototype.onWebkitNeedKey_ it throws an error when trying to dispatch the shaka FakeEvent: UNSPECIFIED_EVENT_TYPE_ERR: DOM Events Exception 0: The Event's type was not specified by initializing the event before the method was called. The only way I can see to avoid that is to create a custom event instead like this:

var event2 = new CustomEvent('encrypted');
event2.initDataType = 'webm';
event2.initData = event.initData;

I'm not sure you'd want to handle it like this just for consistency reasons but this was how I could get around that error just for POC purposes.