New DASH-AVC/264 Guidelines Include Support for 1080p Video
Version 2.0 of the DASH-AVC/264 guidelines, with support for 1080p video and multichannel audio, is now publicly available on the DASH Industry Forum (IF) website.
The new guidelines includes several promised extensions, including one on HD video that moves the recommended baseline from 720p to 1080p.
720p had initially been chosen, according to the initial guidelines released in May, as a "tradeoff between content availability, support in existing devices and compression efficiency." At that time, the baseline video support used the Progressive High Profile Level 3.1 decoder and supported up to 1280x720p at 30 fps.
"The choice for HD extensions up to 1920x1080p and 30 fps is H.264 (AVC) Progressive 12 High Profile Level 4.0 decoder," the new guidelines state, adding support for 4.0 decoders that was lacking in the previous set of guidelines.
In addition, the guidelines also provide a way to handle standard definition (SD) content.
"It is recognized that certain clients may only be capable to operate with H.264/AVC Main Profile," the guidelines state. "Therefore content authors may provide and signal a specific subset of DASH-AVC/264 by providing a dedicated interoperability identifier referring to a standard definition presentation. This interoperability point is defined as DASH-AVC/264 SD."
The new guidelines also cover several multichannel audio options.
"The baseline 1.0 version of DASH-AVC/264 only required support for HE-AACv2 stereo," says Will Law, secretary of DASH IF and Chairman of its Promotions Working Group. "Version 2.0 introduces multichannel Dolby, DTS and also Fraunhofer profiles."
Law also says that there will be a number of DASH-AVC demonstrations around the at IBC at Amsterdam's RAI Convention Centre on September 12, 2013. "These demonstrations will show the latest advancements in the DASH workflow, from encoding, through delivery and playback, including 4K video, HEVC and multichannel audio," says Law. "You'll also see HbbTV and multi-screen applications as well as solutions for DASH use in the broadcast world."
These demonstrations will occur at various booths, including Akamai—the company where Law works as a Principal Architect for Media—Ericsson, Haivision, Microsfot, Nagra, and a host of others.
Digital Primates has been hosting a demonstration of a JavaScript version of a DASH-AVC/264 reference player. The dash.js is also being reviewed for the 1.0 release, according to Law, and release is planned just prior to IBC.
The official version will be launched soon at the DASH IF site but until then the Digital Primates demo can be found on their site. The demo requires Chrome or Internet Explorer 11 (IE); PlayReady DRM playback is currently only available with IE for this demo.
As the DASH IF points out, DASH-AVC/264 "does not intend to specify a full end-to-end DRM system" but it does provide a framework for multiple DRMs to protect DASH content. The guidelines allow the additional of "instructions or Protection System Specific, proprietary information in predetermined locations to DASH content" that has previously been encrypted with what's generally known as the Common Encryption Scheme (ISO/IEC 23001-7).
By Tim Siglin, StreamingMedia
