MPEG-DASH is a new ISO standard poised to help operators create a more efficient multiscreen delivery ecosystem. But what does it actually do? (Be warned, the following post registers a 6.3 on the Nerd Richter Scale).
DASH offers a playlist mechanism that supports either fragmented transport streams (derived from the Apple HLS specification) or MPEG-4 (derived from the Microsoft Smooth Streaming specification). Inside each of those formats, it’s possible to have a common encryption scheme that allows content to be encoded and encrypted just once, with a single master key that can be used by several DRM servers and clients. This is good because it lets content/service providers use one defined format (TS or MPEG-4) for a lot of different DRM specifications, increasing device support without increasing costs. Another plus is that the fragmented MPEG-4 format has been widely endorsed by the industry (see HbbTV in Europe, 3GPP for mobile devices and soon DECE).
A DASH system will have several elements:
Transcoding. You need this for live and file-based content. It transcodes in H.264 format for every required profile. Dual encapsulation is needed in case both TS and MPEG-4 formats are required, though we think that eventually MPEG-4 will win out.
Content encryption and DRM. This will encrypt the TS and MPEG-4 files with a single key. The DRM server will add metadata related to content rights on top of the encrypted file.
Streaming. With the unified DASH playlist mechanism, this will only have to be in two formats — fragmented MPEG-4 or TS. Way less complicated than now!
Storage. This is needed for VOD and catch-up files. With all that put together, an operator can start DASHing towards a superior multiscreen delivery model (…we’ll show ourselves out).