问题
I'm using the VideoJS player and have a CMAF video so I am using HLS and DASH. I'm also using all 3 types of DRM. Fairplay for hls, widevine and playready for dash.
My question is should I include both hls and dash sources in the player and let the player decide which one to play? Or do I detect the browser and only insert the correct url based on that? Also DRM is the same. Can I just add all DRM to the player? Or should I only add the one that applies?
回答1:
The use of HLS vs DASH is typically dictated by the end device and client capabilities and rules.
iOS and Safari typically use HLS and FairPlay, Android, Firefox and Chrome use DASH and Widevine and Windows and Edge use DASH and PlayReady.
Note that Widevine and PlayReady can use the same DASH stream - CENC, Common Encryption standard, allows the same stream to include both Widevine and PlayReady DRM information.
At this time, Apple iOS devices must use HLS for content greater than 10 mins over a mobile network:
2.5.7 Video streaming content over a cellular network longer than 10 minutes must use HTTP Live Streaming and include a baseline 192 kbps HTTP Live stream.
(https://developer.apple.com/app-store/review/guidelines/)
For this reason streams served to Apple devices are usually HLS, while DASH is used for other devices.
CMAF greatly reduces the impact of this by allowing the same segmented media stream be used for both HLS and DASH, with just the 'index' or manifest files being specific to each protocol.
For encrypted content it is a bit more complicated. At this time, FairPlay uses a different AES encryption mode, AES CBC, than Widevine and PlayReady which use AES-CTR. This means you still need two copies of the media to serve encrypted content streams.
This is changing as Widevine and PlayReady now have announced support for AES-CBC as well as AES-CTR, but it will take some time for this to roll out to deployed devices.
来源：https://stackoverflow.com/questions/61948356/what-is-the-reccomended-way-to-use-hls-and-dash-drm-in-a-player