Everything you need to know about h.265/HEVC on your PC

Video is the Internet. The networking giant Cisco estimates it consumed about 70 percent of all online traffic in 2014, and that share will rise to between 80 and 90 percent by 2018. The ever-increasing volume of video content is due to a perfect storm of rapidly increasing demand and quality. Established players like Netflix are upping their game to 4K and networks that traditionally haven’t had a place in video, like Facebook, are embracing it.

There’s no reversing this trend; video is going to become more popular, and it will consume more bandwidth. But advanced video compression software, called codecs, can help reduce how much bandwidth video hogs. This year, the H.265 (or HEVC) standard is generating major buzz for its huge gains in compression efficiency, and may be poised to overtake its forefather H.264 — the foundation of most online video. You can’t fully enjoy it, however, unless your PC is prepared, so here’s how to get on board.

What is H.265, and how is it different from HEVC?

H.265, or High Efficiency Video Coding, is a new video coding standard that specifies how to decode video. It’s basically the video equivalent of a .JPEG file. The codec helps your computer understand how a stream of data can be displayed as a video file rather than gobs of randomly distributed colors.

Interestingly, a video coding standard doesn’t define how video is encoded into a file. Tom Vaughan, the Vice President of product management and marketing at MultiCoreWare, developer of the open-source x265 encoder, clarified this. “When you define a codec, the only thing really defined by the spec is the syntax of the compressed video stream, and the method to decode it. Video encoding isn’t defined by the standard.” This is why there are many different video encoders, and some are more efficient than others.

So, what’s the difference between H.265 and HEVC? There isn’t one. Each is a different name for the same codec. The standard was defined by the Moving Picture Experts Group (MPEG) and the Video Coding Experts Group (VCEG), and each calls it by a different name, but the standard is the same.

And what about x265? That’s the open-source encoding project, not the standard. It’s the most popular way to encode video to HEVC, but it’s not the only choice.

Why is the new codec necessary?

H.264 is an incredibly popular codec that forms the basis of most online video shown today. It was finalized all the way back in 2003 and really started to catch on a few years later. This leads to an inevitable question: If it’s been working for so long, and is compatible with virtually every device consumers own today, why replace it?

Efficiency is the answer. The less data a codec can use to display an image without degrading its quality, the more efficient it is. If codec A and codec B both display the same image quality, but the size of A’s file is twenty percent smaller, then A is more efficient.

Greater efficiency means video can be shown at the same quality while consuming less bandwidth, or bandwidth can be maintained to achieve greater quality. “At the constrained bitrates you might see on a typical PC,” says Tom Vaughan, “we can be up to twice as efficient as h.264.”

How demanding is it?

Higher efficiency usually comes with a cost: complexity. H.265 is far more difficult to encode as a result of its complexity, and can require up to 10 times the compute power to encode at the same speed as H.264.

This is mostly a problem for companies producing content rather than one for consumers, at least for the time being. As H.265 grows in popularity, however, home users will start to use the new codec to reduce file sizes and decrease upload times. Users who’ve become accustomed to their three-year-old dual-core desktop encoding video in real time, or quicker, may be surprised by the lengthy processing times of encoders compatible with H.265.

Decoding is less of an issue, but load roughly doubles compared to H.264. Throw in the jump to 4K, which is frequently encoded to H.265, and the leap in required compute power is nothing to laugh at. However, most systems that might choke on decoding a 4K HEVC stream or file can’t output 4K. The overlap between systems that can output Ultra HD and those that are too slow to decode HEVC is slim.

What can decode it?

Any computer can decode H.265 using software (in theory, at least). All that’s mandatory is software capable of handling H.265 and a file or stream encoded in it. The freeware VideoLAN player is currently your best bet, but support will be native to PCs with the release of Windows 10.

Software decoding isn’t the best option, however, because it’s not terribly efficient. Building a hardware decoder into a chip allows for more efficient operation, which means better performance on chips with modest grunt and improved efficiency. On the downside, though, this approach takes up valuable die space on a CPU or GPU. HEVC is not popular yet, and developing a hardware decode means designing new silicon — a lengthy process.

There’s just one exception at this moment, and that’s the GTX 960, which is the first and only video card to have full hardware decode support for H.265. Arguably it’s powerful enough to not need it, but the feature boosts efficiency and may help the GPU decode video without active cooling.

AMD plans to add H.265 hardware decode to it’s mid-2015 notebook APUs, code-named Carrizo, which presumably means we’ll see the same appear in a variety of other AMD Radeon products. Intel has made no announcement, but leaks from rumor sites like CPU World, as well as our own sources, hint it’s coming in Skylake. Such speculation is easy to believe, because the timing would be perfect. Intel also recently announced a driver update adding software decode support to select fourth-gen and fifth-gen Core chips.

How can I encode my own HEVC video?

Encoding with HEVC is, as explained, much more demanding than other video codecs. You’ll likely find that your videos take many times longer than before, and real-time encoding is virtually unheard of with home PCs. With that said, switching from an older standard to H.265/HEVC can substantially reduce the file size of your video library. It can also make streaming between devices easier.

There are several converters available for free including Handbrake, Internet Friendly Media Encoder, MediaCoder and DivX Converter. For $40, CyberLink’s Media Espresso is the easiest to use, so it may appeal to users who prefer a streamlined solution. All of these can take various input formats and transcode them to HEVC.

What’s next for H.265/HEVC on the PC?

2015 will be a big year for HEVC on your home computer. Hardware-decode support will become more prevalent, and it’s likely that Intel will add some hardware support as a feature in sixth-generation Core processor. This will entirely solve the potential performance issues facing high-quality, UltraHD, HEVC video.

Microsoft’s inclusion of support in Windows 10 will place another piece of the puzzle. It will let users play H.265 files without a third-party application, which is necessary for the codec to see widespread adoption on computers. Some old systems may have difficulty rendering the format, but most modern systems will be quick enough to handle the burden.

Once hardware and operating system support is in place, there will be only one more obstacle: content owners. Studios jealously guard 4K content because of its incredible quality and potential for profit, and bringing such content to the PC could make it easier to rip off. It will come, eventually, but when?