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Delivering high-quality audio in DASH.

Broadcasters and online service providers have seen a tremendous increase in the complexity of their workflows as the ecosystem for online entertainment delivery has evolved. Initiatives such as DASH and UltraViolet are designed to increase the ubiquity and break through the vertical ecosystems that exist in the market today and lead to this market fragmentation and operational complexity.

Dolby believes that DASH is an idea whose time has come and was one of the first companies to join the DASH Promoters Group. Dolby is working with its partners to promote the adoption of MPEG-DASH standard in the market. As a charter member of the DASH Industry Forum (DASH-IF), Dolby wants to make sure that premium audio is available to consumers as DASH is rolled out.

MPEG-DASH, ratified by MPEG in November 2011, has been gaining traction as a mainstream delivery format for streaming content over the internet. MPEG-DASH is targeted to be a single standard that could resolve the fragmentation in streaming protocols that exists in the market today. However, it will take time before MPEG-DASH is ubiquitously and consistently supported across the multiscreen ecosystem. The commercial deployment of MPEG-DASH has started to move forward, and the first mass market live public trial, presented by Belgian public broadcaster VRT, was run last summer in support of the 2012 London Olympics. This commercial demonstration featured a live video stream encoded using the MPEGDASH ISO Base Media File Format Live Profile, delivered through Belgacom's content delivery network to a range of device categories, including tablets, smartphones, and PCs running iOS, Android, and Windows operating systems.

Using MPEG-DASH they were able to reap the benefits of adaptive bit rate technology to automatically adapt the video playout to the available bandwidth. This trial was focused on video and did not provide multiple profiles for audio. Needing to support a minimum audio bitrate of 64Kbps and wanting to ensure seamless switching across different profiles, a 64Kbps bitrate was use across all profiles. By using a single audio bitrate they were not able to highlight the benefits of ABR for audio. Pairing 64Kbps audio with full 720p HD video diminishes the QoE for end users that are used to traditional broadcast services that provide full high quality 5.1 surround sound with their HD channels. This did not have to be the case if Dolby[R] Digital Plus had been used. Dolby[R] Digital Plus in this scenario could maintain the QoE across all bit rates by enabling seamless bit rate switching for all channel configurations.

Dolby is closely collaborating with its partners to provide Dolby[R] Digital Plus and DASH-AVC/264 video at different bit rates while supporting seamless adaptive switching, seamless channel switching, and seamless ad insertion, thereby enabling service providers to deliver high-quality multichannel audio entertainment to consumers on any compatible device while lowering their operational costs. Doing so will help the DASH standard become more universally adopted and allow even more service providers to be able to leverage these technologies.

Dolby is currently demonstrating how this can be done with DASH. Specifically, Dolby has been working to show this in conjunction with Hybrid Broadcast Broadband TV (HbbTV) initiative. This initiative aims to bring about the harmonization of the delivery of both broadcast and broadband services to the viewer through connected TVs and set top boxes. MPEG-DASH has been incorporated into version 1.5 of the HbbTV. HbbTV 1.5 will be widely used by European broadcasters for interactive services on connected televisions and includes Dolby[R] Digital Plus as a mandatory requirement whenever the decoder implemented in a device supports it. This requirement addresses some of the concerns that broadcasters had regarding the support for end-to-end multichannel audio across their networks.

The following diagram outlines the demo that Dolby and some of its partners are providing to show how Dolby[R] Digital Pluss augments the value of DASH in HbbTV.

As noted earlier, HbbTV mandates Dolby[R] Digital Plus (DD+). Dolby[R] Digital Plus is the only codec in HbbTV that ensures 5.1 where physically possible and as such it enables simple and reliable audio encoding workflows. It ensures that the service will work end-to-end and provide seamless bitrate and channel configuration switching. With this seamless switching, service providers will be able to use a single stream for audio that allows them to match the quality of the audio with that of the video as the available bandwidth changes.

Dolby[R] Digital Plus will also address loudness issues from broadcast and VoD service providers due to broadband content from/to metadata-incapable encoders or decoders further assisting service providers in delivering a high quality of experience. With 5.1 channel Dolby[R] Digital Plus, DASH, and DRM, broadcasters will be able to deliver more valuable content (e.g. VoD) using HbbTV.

Dolby technology has been selected by leading online video services including Netflix, HBO Go[R], Vudu[TM], Best Buy[R] CinemaNow[R], Samsung[TM] Acetrax[TM], Dixons KnowHow[TM] Movies, Voddler[R], Apple[R] iTunes[R], and Amazon[R] Instant Video. Dolby[R] Digital Plus is the end-to-end solution for delivering premium multichannel audio and has the broadest reach across consumer devices, Dolby[R] Digital Plus is deployed in over 1.3 billion devices worldwide. By leveraging this reach across services and devices and by working with the DASH-IF and with international standards bodies, Dolby hopes to accelerate the deployment of MPEG-DASH across all applications--mobile, broadcast, and internet--and to enable interoperability between all MPEG-DASH content and connected devices to the greatest degree possible.

At last year's NAB, Dolby announced the availability of a development kit to bring the full power of Dolby[R] Digital Plus premium-quality multichannel audio to partners that leverage the MPEG Dynamic Adaptive Streaming over HTTP (MPEG-DASH) standard. This development kit enables Dolby's current and future partners, such as encoder vendors and digital rights management (DRM) vendors, to easily implement and test Dolby[R] Digital Plus for products and services in the online video ecosystem. The development kit includes test vectors as well as specifications that describe how Dolby[R] Digital Plus can be signaled and transported within MPEG-DASH as well as Microsoft[R] Smooth Streaming, and Apple HTTP Live Streaming (HLS).

Key service providers and device manufacturers recognize that consumers care about great sound. While people are increasingly using their tablets and smart phones for watching online videos, listening to music, playing games and video chatting, the fact is that the primary consumption of entertainment content is through peoples existing TVs and home theater systems, where they are used to getting a high quality sound experience delivered in 5.1 surround sound. As more consumers enjoy streaming content on multiple screens, it's increasingly important that the entertainment experiences are the best quality, regardless of delivery medium and playback devices.

Dolby[R] Digital Plus enables the delivery of high-quality audio to any compatible device and any distribution workflow, including broadcast, over-the-top (OTT), online, and on demand. It includes scalable, adaptive, and bandwidth-efficient multichannel coding designed for bandwidth-constrained delivery networks, as well as technologies such as loudness control and device-playback sound optimization. Widely supported within the digital entertainment ecosystem, Dolby[R] Digital Plus enables service providers to deliver high-quality multichannel audio entertainment to consumers on any compatible device while lowering their operational costs, making it the preferred audio solution for artists, operators, carriers, and device makers worldwide.
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Title Annotation:THE DASH HANDBOOK
Publication:Streaming Media
Date:Jun 1, 2013
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