n s support CMAF. The problem is that CMAF also
enables two incompatible common encryption
modes: cipher block chaining (CBC) and count-
er mode (CTR). CBC is supported by Apple’s
FairPlay and Google Widevine, but not by Mi-
crosoft PlayReady, while CTR is supported by
Widevine and PlayReady, but not FairPlay. So
you still can’t create one set of encrypted files
that will play on all major platforms.
Basically, it’s a stare-down between Microsoft and Apple to see who blinks first—Microsoft
to incorporate CBC or Apple to support CTR.
There have been multiple reports that Microsoft
has already blinked, but I couldn’t confirm this
directly with Microsoft.
Even if Microsoft or Apple does blink, it will
take a while for many publishers to feel com-
fortable delivering one data set to all targets,
particularly those who are switching HLS from
MPEG2 Transport stream fragments to frag-
mented MP4, which may not be compatible
with older, but still relevant, targets platforms.
Obviously, if you don’t need DRM, the CBC/
CTR issue is irrelevant, but you still have the
same concerns about backward compatibility
with HLS delivered via f MP4.
At the moment, all we can report is that the
EME standard is stuck in the standards bodies,
though that should be resolved pretty quickly. At the implementation level, we’re getting
closer to that holy grail of a single encrypted
format for universal distribution, but for the
time being, that appears to be a ways off.
Jan Ozer ( firstname.lastname@example.org) is a streaming
media producer and consultant, a frequent contributor to industry
magazines and websites on streaming-related topics, and the
author of Video Encoding by the Numbers. He blogs frequently at
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