High-efficiency video coding: Delivering ultra HD video content

Display technologies are evolving at an unprecedented rate. They have evolved so much that we can now see the minutest picture details on our devices – be it television sets, tablets or smart phones. Not very long ago, we started talking about high-definition content, and then came full HD that gave a new dimension to multimedia experience and now we are talking about ultra HD (UHD), which delivers four-times the picture resolution of 1080p full HD.

In parallel with the evolution of display technology, online streaming has become the preferred medium for video content consumption. Delivering UHD over legacy carriers would be a nightmare without a right compression technology. High-efficiency video coding (HEVC) is a technology that addresses this problem and promises to deliver video playback without any jitter, even on a low bandwidth connection. Let’s look at how HEVC solves the problem of delivering UHD content online and helps in adoption of UHD resolution in case of satellite and terrestrial broadcast.

What is HEVC and what makes it a differentiator?

The Joint Collaborative Team on Video Coding released the final publication of high-efficiency video coding (HEVC) standard worldwide in the fourth quarter of 2013. HEVC is a video coding standard that would give users a much better quality (at the same bit-rate) than its predecessor H.264 and users would be able to enjoy a multimedia experience that is one step ahead of high definition – an ultra-high definition.

While native parallel tools (Tiles and WPP) introduced in the standard make it a multi-core friendly codec, more exhaustive prediction modes, hierarchical block partitioning strategy, and improved post processing are a few of the key enhancements that make HEVC stand apart to deliver the quality required by the UHDTV revolution.

The Impact of HEVC

Online streaming is fast becoming the most preferred medium to watch video. In fact, more and more people watch movies, TV programs, etc., on YouTube rather than on their TV sets. Paid viewership is also increasing by the day, leading to a steep increase in consumers’ average spending on online video streaming.

According to statistics published by YouTube, “Over six billion hours of video are watched each month on YouTube, that’s almost an hour for every person on earth and 50% more than last year. Around 100 hours of video content is uploaded to YouTube every minute.” Given this scenario, it is a must for content providers/aggregators to deliver content at a lower cost, while improving the quality of the video.

HEVC Cuts Online Viewing Costs

HEVC would play a significant role in further bringing down the cost of online video viewing. With the current infrastructure, whatever a user spends for video streaming can be reduced by 50% by using HEVC technology because HEVC provides 50% more compression compared to legacy technologies. Alternatively, by deploying HEVC, the quality of the content can be upgraded without any extra load on the channels and users can enjoy larger than life experience at the same cost. Using HEVC on 3G/4G network is certainly going to benefit the pocket of the mobile user and would encourage more video viewing over mobile networks. In fact, Vodafone is already marketing itself as – “A network for 24×7 streaming” with regards to e-learning and online video viewership.”

HEVC Offers Better Quality

A video standard is said to be more efficient if it achieves better peak signal-to-noise ratio or loses lesser quality for a given bit-rate during encode-decode cycle. Figure 1 below compares the PSNR data, obtained for an Aricent-generated high motion content for HEVC and H.264 codecs. It is seen clearly that HEVC consistently leads H.264 and delivers better PSNR at all bitrates. Experiments conducted at Aricent reveal that HEVC is able to save almost 50% bit-rates for most of the standard content scenarios and hence opens up doors for 4K video streaming on the current networks.

HEVC Provides Smoother Playback

Frequent re-buffering and a jerky playback due to lack of speed (bandwidth) is very annoying and has been a concern. As a result, there are still a huge number of people who prefer to watch downloaded content rather than watching it online. By deploying HEVC, channel traffic is reduced by 50%. This extra buffer can be used to avoid re-buffering and providing the user with a smooth playback experience, without any interruptions.

The Internet speed fluctuations, variations in the content bitrate and instantaneous increase in the (computational) complexity of the video cause undesirable frame drops or re-buffering during streaming. Adaptive streaming is a technology that provides a user an option to switch between the contents of various bit-rates in accordance with the available bandwidth or CPU speed. MPEG-DASH, Microsoft Smooth Streaming and Apple’s HTTP Live Streaming, are a few of the leading technologies that address frame drop issues and provide a smooth playback on a user’s device by adapting between the right content.

HEVC Power Concerns

No doubt HEVC is computationally more intensive than H.264 and obviously bound to consume relatively more power especially during encoding. Codec vendors are striving hard to provide power efficient implementations on ARM A15/Krait and other similar platforms by writing better codes. Also, general-purpose computing on graphics processing units technology is being aggressively leveraged to reduce power consumption and provide a user the HEVC advantages without any additional battery overheads.

ARM Mali T6xx series based implementations are being encouraged because they can offload the CPU’s load to GPU Compute and bring down HEVC’s power requirements drastically. Hardware implementation of a codec is another alternative to combat power consumption, but due to patent issues involved in HEVC standard, most equipment/device manufacturers are delaying the hardware realizations of HEVC.

HEVC Enables UHDTV Broadcasting

Satellite television will also benefit greatly with HEVC. Leading DTH service providers are doing necessary homework to upgrade their content to reap the benefits of the HEVC technology. The DTH ecosystem is laying the foundation for UHD content delivery so that UHDTV broadcasting can become main-stream and enter the consumers’ television sets by 2016. Ultra HD-enabled televisions are already being manufactured by Sony, Samsung, LG and other consumer electronics leaders. NHK (Nippon Hōsō Kyōkai), a Japanese public broadcaster, is preparing to broadcast UHD content in Japan in the near future. In fact, recently NHK announced an 8K sensor that is capable of shooting at 120 frames-per-second.

UHDTV broadcasting will be mainstream very soon, and HEVC will play a vital role in delivering the required compression to complement the technology. VP9 is emerging as a competing technology to HEVC and has the advantage of being a license free codec. There are competing technologies emerging. Nevertheless, due to better compression efficiency, wider color space/format coverage, and HEVC coming from a more reliable standard body, HEVC is the leading technology for video compression this decade.


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