H.265 and VP9: delivering better pixels at 4K resolutions and beyond

If you've recently used your smartphone to shoot videos of cats chasing after laser lights and upload them to the internet, you've probably saved them in theH.264/MPEG-4 AVC video format - the most popular video codec in use today.

The main competitor to H.264 is VP8, a royalty-free format developed by Google and primarily used for video conferencing (think Google+ Hangouts and WebRTC).

There are several reasons why H.264 - or VP8 - will continue to be used for a few years to come. Essentially, most mobile and embedded devices today already support full hardware H.264 decoding. Additionally, most broadcasting equipment has now migrated from MPEG-2 to H.264 and upgrading it again will be a costly endeavor.

The battle of the codecs: H.265 and VP9

But there are also valid reasons why new video formats will rapidly see adoption for mobile devices, smart TVs or smart cars. For example, the explosive growth of video sharing and the emergence of high quality 4K content are a few of the factors driving the emergence of these new standards.

The good news for users who want to stream high-resolution videos faster is that several options are now available - some of which are starting to make a visible impact. In this article, we are going to focus on two of them: H.265 and VP9.

Max Sharabayko compares next-generation H.265 and VP9 video formats in his blog

H.265 is being widely adopted, and the ITU-T Video Coding Experts Group has already mandated 10-bit as the minimum colour depth for Ultra HD broadcast. The ITU-R UHDTV Recommendation BT.2020, approved in October 2015, represented the next step in the continuous evolution of television. Earlier this year, the ITU-T group announced BT.2100, a new standard for high dynamic range TV; here is an extract from the press release :

This latest ITU-R HDR-TV Recommendation BT.2100 brings a further boost to television images, giving viewers an enhanced visual experience with added realism. The HDR-TV Recommendation allows TV programmes to take full advantage of the new and much brighter display technologies. HDR-TV can make outdoor sunlit scenes appear brighter and more natural, adding highlights and sparkle. It enhances dimly lit interior and night scenes, revealing more detail in darker areas, giving TV producers the ability to reveal texture and subtle colours that are usually lost with existing Standard Dynamic Range TV.

If you want to read more on this topic, my colleague Simon Forrest has written a comprehensive article covering the benefits of adding 10-bit color depth for H.265 encoding and decoding.

Meanwhile, VP9 is being promoted by Google as the default format for streaming videos on YouTube, and has enjoyed some success as a 4K format.

We've already worked closely with Google and our partners to design GPU compute-based software decoders for VP9. Imagination has demonstrated how PowerVR Rogue GPUs can deliver power-efficient VP9 decoding at Full HD resolutions right from the YouTube media player.

A lot of VP9 adopters have demanded the implementation of higher bit depth to ensure superior image quality and encoding efficiency at high resolutions. This is why Google has announced HBD (High Bit Depth), a brand new profile for VP9 which allows for high quality 4K video content to be viewed on TVs.

Multi-standard PowerVR video IP cores to the rescue

However, in order to achieve the best possible performance and power efficiency, a dedicated PowerVR VPU (Video Processing Unit) is required to provide full hardware acceleration for any video format.

Imagination is the world's largest supplier of video IP cores and has been a lead adopter of H.265, H.264, VP8 and many other video formats. We have a proud tradition of designing proven, multi-standard PowerVR video processors. One such example is the recently-announced PowerVR Series5 encoder family which has been designed for the higher resolutions, frame rates and bitrates of 4K video.

To learn more about the benefits of our PowerVR video IP, visit www.imgtec.com/powervr/video.asp and keep coming back to our blog.