This is something that initially caught me off-guard when I first realized it, but AMD historically hasn’t liked to talk about their GPU plans much in advance. On the CPU size we’ve heard about Carrizo and Zen years in advance. Meanwhile AMD’s competitor in the world of GPUs, NVIDIA, releases some basic architectural information over a year in advance as well. However with AMD’s GPU technology, we typically don’t hear about it until the first products implementing new technology are launched.

With AMD’s GPU assets having been reorganized under the Radeon Technologies Group (RTG) and led by Raja Koduri, RTG has recognized this as well. As a result, the new RTG is looking to chart a bit of a different course, to be a bit more transparent and a bit more forthcoming than they have in the past. The end result isn’t quite like what AMD has done with their CPU division or their competition has done with GPU architectures – RTG will talk about both more or less depending on the subject – but among several major shifts in appearance, development, and branding we’ve seen since the formation of the RTG, this is another way in which RTG is trying to set itself apart from AMD’s earlier GPU groups.

As part of AMD’s RTG technology summit, I had the chance to sit down and hear about RTG’s plans for their visual technologies (displays) group for 2016. Though RTG isn’t announcing any new architecture or chips at this time, the company has put together a roadmap for what they want to do with both hardware and software for the rest of 2015 and in to 2016. Much of what follows isn’t likely to surprise regular observers of the GPU world, but it none the less sets some clear expectations for what is in RTG’s future over much of the next year.

DisplayPort 1.3 & HDMI 2.0a: Support Coming In 2016

First and foremost then, let’s start with RTG’s hardware plans. As I mentioned before RTG isn’t announcing any new architectures, but they are announcing some of the features that the 2016 Radeon GPUs will support. Among these changes is a new display controller block, upgrading the display I/O functionality we’ve seen as the cornerstone of AMD’s GPU designs since GCN 1.1 was first launched in 2013.

The first addition here is that RTG’s 2016 GPUs will be including support for DisplayPort 1.3. We’ve covered the announcement of DisplayPort 1.3 separately in the past, where in 2014 the VESA announced the release of the 1.3 standard. DisplayPort 1.3 will introduce a faster signaling mode for DisplayPort – High Bit Rate 3 (HBR3) – which in turn will allow DisplayPort 1.3 to offer 50% more bandwidth than the current DisplayPort 1.2 and HBR2, boosting DisplayPort’s bandwidth to 32.4 Gbps before overhead.

The purpose of DisplayPort 1.3 is to offer the additional bandwidth necessary to support higher resolution and higher refresh rate monitors than the 4K@60Hz limit of DP1.2. This includes supporting higher refresh rate 4K monitors (120Hz), 5K@60Hz monitors, and 4K@60Hz with higher color depths than 8 bit per channel color (necessary for a good HDR implementation). DisplayPort’s scalability via tiling has meant that some monitor configurations have been possible even via DP1.2 by utilizing MST over multiple cables, however with DP1.3 it will now be possible to support those configurations in a simpler SST configuration over a single cable.

For RTG this is important on several levels. The first is very much pride – the company has always been the first GPU vendor to implement new DisplayPort standards. But at the same time DP1.3 is the cornerstone of multiple other efforts for the company. The additional bandwidth is necessary for the company’s HDR plans, and it’s also necessary to support the wider range of refresh rates at 4K necessary for RTG’s Freesync Low Framerate Compensation tech, which requires a 2.5x min:max ratio to function. That in turn has meant that while RTG has been able to apply LFC to 1080p and 1440p monitors today, they won’t be able to do so with 4K monitors until DP1.3 gives them the bandwidth necessary to support 75Hz+ operation.

Meanwhile DisplayPort 1.3 isn’t the only I/O standard planned for RTG’s 2016 GPUs. Also scheduled for 2016 is support for the HDMI 2.0a standard, the latest generation HDMI standard. HDMI 2.0 was launched in 2013 as an update to the HDMI standard, significantly increasing HDMI’s bandwidth to support 4Kp60 TVs, bringing it roughly on par with DisplayPort 1.2 in terms of total bandwidth. Along with the increase in bandwidth, HDMI 2.0/2.0a also introduced support for other new features in the HDMI specification such as the next-generation BT.2020 color space, 4:2:0 chroma sampling, and HDR video.

That HDMI has only recently caught up to DisplayPort 1.2 in bandwidth at a time when DisplayPort 1.3 is right around the corner is one of those consistent oddities in how the two standards are developed, but none the less this important for RTG. HDMI is not only the outright standard for TVs, but it’s the de facto standard for PC monitors as well; while you can find DisplayPort in many monitors, you would be hard pressed not to find HDMI. So as 4K monitors become increasingly cheap – and likely start dropping DisplayPort in the process – supporting HDMI 2.0 will be important for RTG for monitors just as much as it is for TVs.

Unfortunately for RTG, they’re playing a bit of catch-up here, as the HDMI 2.0 standard is already more than 2 years old and has been supported by NVIDIA since the Maxwell 2 architecture in 2014. Though they didn’t go into detail, I was told that AMD/RTG’s plans for HDMI 2.0 support were impacted by the cancelation of the company’s 20nm planar GPUs, and as a result HDMI 2.0 support was pushed back to the company’s 2016 GPUs. The one bit of good news here for RTG is that HDMI 2.0 is still a bit of a mess – not all HDMI 2.0 TVs actually support 4Kp60 with full chroma sampling (4:4:4) – but that is quickly changing.

FreeSync Over HDMI to Hit Retail in Q1’16

After pushing DisplayPort Freesync out the door earlier this year, back at Computex 2015 AMD began demonstrating a further Freesync proof-of-concept implementation: FreeSync over HDMI.

Implemented over a customized version of HDMI 1.4a and utilizing a prototype Realtek timing controller (TCON), AMD was able to demonstrate variable refresh rate technology running over HDMI. At the time of the presentation AMD was very clear that the purpose of the presentation was to shop around the concept and to influence the various members of the HDMI consortium, but they were also clear that bringing variable refresh rate tech to HDMI was something the company wanted to bring to retail sooner than later.

Sooner, as it turns out, was the operative word there. As part of their presentation last week, RTG has announced that FreeSync over HDMI will be heading to retail, and that it will be doing so very soon: Q1’16. This is just a year after the first DisplayPort adaptive sync monitors hit retail, which for a display technology is a rather speedy turnaround from proof of concept to retail product.

Now there are some key technical differences from FreeSync over DisplayPort(FS-DP) that should be noted here. Unlike FS-DP, which was just AMD’s implementation of DisplayPort adaptive sync on their GPUs and software stack, FS-HDMI is not an open standard, at least not at this time. HDMI does not have a variable refresh rate technology standard, and while RTG is pushing to have one included in a future version of HDMI, the HDMI consortium moves too slowly for RTG’s tastes. As a result RTG is looking to go it alone, and will be implementing FS-HDMI by creating a vendor specific extension for HDMI.

The use of vendor specific extensions is perfectly legal within the HDMI standard, but it does mean that FS-HDMI is proprietary, at least until such a time where the HDMI standard adopts a common variable refresh rate standard. This means that FS-HDMI monitors will need to support RTG’s proprietary extensions, which in turn requires TCON/monitor vendors to work a bit more closely with RTG than was necessary with FS-DP. Meanwhile RTG for their part hasn’t yet decided what to do about the proprietary nature of their implementation – they are open to sharing it, but they also want to retain control and avoid any scenario that results in outright balkanization of HDMI variable refresh rate technology. The fact that it’s an RTG-controlled specification calls into question whether any other GPU vendor would want to implement it in the first place – so concerns about openness may prove to be moot – but it does mean that it’s going to be up to RTG to make or break FS-HDMI.

Perhaps more surprising, and certainly a feather in RTG’s cap, is that RTG has brought so many TCON vendors on-board so early. Along with Realtek, Novatek and Mstar will all be producing TCONs that support FS-HDMI, so TCONs will be available from multiple vendors relatively quickly. With variable refresh rate tech it’s the TCONs that really decide whether the tech is supported, so this is an important set of partnerships for RTG to lock in so soon. Meanwhile traditional AMD/RTG display partners such as Acer, LG, and Samsung will be producing retail monitors with FS-HDMI capabilities.

Meanwhile at this point RTG isn’t talking about GPU compatibility in great detail, however it sounds like FS-HDMI support will be brought over to some of RTG’s current GPUs. Most likely these are the GCN 1.1+ Radeon 300 series cards, with GCN 1.1 also being the minimum requirement for FS-DP. AMD’s Carrizo APU should also support the technology, and RTG is specifically promoting that notebooks implementing an APU + dGPU Radeon dual graphics configuration will also support FS-HDMI, an important development especially given the fact that DisplayPort support is non-existent on consumer AMD laptops.

In fact the lack of DisplayPort availability in displays overall is a big part of why RTG has pursued this. According to numbers from RTG, only about 30% of all monitors sold include a DisplayPort, while the other 70% are only implementing HDMI or HDMI + DVI. Consequently FS-DP is an inherently limited market and the majority of monitor buyers will never be able to use FS-DP. Meanwhile from what I hear the actual cost of implementing variable refresh rate support on a TCON is very low, which means that RTG could get far greater penetration for FreeSync by extending it to support HDMI, not to mention bringing down the overall cost of entry-level FreeSync monitors. We’re still talking about a highly price sensitive commodity market – after all, there’s a reason that most monitors don’t ship with a DisplayPort – but if the costs of adding FreeSync are as low as RTG hints, then there is a market for consumers who would spend a bit more on a variable refresh rate monitor but don’t know anything about display I/O standards beyond HDMI.

Finally, along those lines, it should be no surprise that the first FS-HDMI monitors that have been announced are all focused on lower cost and lower resolution displays. That FP-HDMI is being implemented over HDMI 1.4 immediately rules out 4K monitors, so instead all announced monitors are 1080p or ultra-wide 21:9 aspect ratio 2560x1080 and 3440x1440 monitors. Otherwise there are a few more unknowns here that I expect we’ll see addressed ahead of the Q1 launch, particularly which monitors will support a wide-enough range of rates for low framerate compensation to work.

FreeSync Laptops: Shipping Now

Along with the FreeSync over HDMI announcement, RTG also used their event to announce the first FreeSync-capable laptop, the Lenovo Y700. One of the models of the laptop ships with a variable refresh rate capable 15.6” 1080p IPS panel, and when paired up with a Carrizo APU and R9 M380 GPU, can utilize FreeSync to control the refresh rate. The one notable limitation here is that while this otherwise a rather typical DisplayPort adaptive sync setup within a laptop, the specific panel being used here is only supports a range of 40Hz to 60Hz, so the first FreeSync laptop has a narrow effective range and can’t support LFC.

High Dynamic Range: Setting the Stage For The Next Generation

The final element of RTG’s visual technologies presentation was focused on high dynamic range (HDR). In the PC gaming space HDR rendering has been present in some form or another for almost 10 years. However it’s only recently that the larger consumer electronics industry has begun to focus on HDR, in large part due to recent technical and manufacturing scale achievements.

Though HDR is most traditionally defined with respect to the contrast ratio and the range of brightness within an image – and how the human eye can see a much wider range in brightness than current displays can reproduce – for RTG their focus on HDR is spread out over several technologies. This is due to the fact that to bring HDR to the PC one not only needs a display that can cover a wider range of brightness than today’s displays that top out at 300 nits or so, but there are also changes required in how color information needs to be stored and transmitted to a display, and really the overall colorspace used. As a result RTG’s HDR effort is an umbrella effort covering multiple display-related technologies that need to come together for HDR to work on the PC.

The first element of this – and the element least in RTG’s control – is the displays themselves. Front-to-back HDR requires having displays capable not only of a high contrast ratio, but also some sort of local lighting control mechanism to allow one part of the display to be exceptionally bright while another part is exceptionally dark. The two technologies in use to accomplish this are LCDs with local dimming (as opposed to a single backlight) or OLEDS, which are self-illuminating, both of which until recently had their own significant price premium. The price on these styles of displays is finally coming down, and there is hope that displays capable of hitting the necessary brightness, contrast, and dimming levels for solid HDR reproduction will become available within the next year.

As for RTG’s own technology is concerned, even after HDR displays are on the market, RTG needs to make changes to support these displays. The traditional sRGB color space is not suitable for true HDR – it just isn’t large enough to correctly represent colors at the extreme ends of the brightness curve – and as a result RTG is laying the groundwork for improved support for larger color spaces. The company already supports AdobeRGB for professional graphics work, however the long-term goal is to support the BT.2020 color space, which is the space the consumer electronics industry has settled upon for HDR content. BT.2020 will be what 4K Blu Rays will be mastered in, and in time it is likely that other content will follow.

Going hand-in-hand with the BT.2020 color space is how it’s represented. While it’s technically possible to display the color space using today’s 8 bit per color (24bpp) encoding schemes, the larger color space would expose and exacerbate the banding that results from only having 256 shades of any given primary color to work with. As a result BT.2020 also calls for increasing the bit depth of images from 8bpc to a minimum of 10bpc (30bpp), which serves to increase the number of shades of each primary color to 1024. Only by both increasing the color space and at the same time increasing the accuracy within that space can the display rendering chain accurately describe an HDR image, ultimately feeding that to an HDR-capable display.

The good news here for RTG (and the PC industry as a whole) is that 10 bit per color rendering is already done on the PC, albeit traditionally limited to professional grade applications and video cards. BT.2020 and the overall goals of the consumer electronics industry means that 10 bit per color and BT.2020's specific curve will need to become a consumer feature, and this is where RTG’s HDR presentation lays out their capabilities and goals.

The Radeon 300 series is already capable of 10bpc rendering, so even older cards if presented with a suitable monitor will be capable of driving HDR content over HDMI 1.4b and DisplayPort 1.2. The higher bit depth does require more bandwidth, and as a result it’s not possible to combine HDR, 4K, and 60Hz with any 300 series cards due to the limitations of DisplayPort 1.2 (though lower resolutions with higher refresh rates are possible). However this means that the 2016 Radeon GPUs with DisplayPort 1.3 would be able to support HDR at 4K@60Hz.

And indeed it’s likely the 2016 GPUs where HDR will really take off. Although RTG can support all of the basic technical aspects of HDR on the Radeon 300 series, there’s one thing none of these cards will ever be able to do, and that’s to directly support the HDCP 2.2 standard, which is being required for all 4K/HDR content. As a result only the 2016 GPUs can play back HDR movies, while all earlier GPUs would be limited to gaming and photos.

Meanwhile RTG is also working on the software side of matters as well in conjunction with Microsoft. At this time it’s possible for RTG to render to HDR, but only in an exclusive fullscreen context, bypassing the OS’s color management. Windows itself isn’t capable of HDR rendering, and this is something that Microsoft and its partners are coming together to solve. And it will ultimately be a solved issue, but it may take some time. Not unlike high-DPI rendering, edge cases such as properly handling mixed use of HDR/SDR are an important consideration that must be accounted for. And for that matter, the OS needs a means of reliably telling (or being told) when it has HDR content.

Finally at the other end of the spectrum will be software developers. While the movie/TV industries have already laid the groundwork for HDR production, software and game developers will be in a period of catching up as most current engines implicitly assume that they’ll be rendering for a SDR display. This means at a minimum reducing/removing the step in the rendering process where a scene is tonemapped for an SDR display, but there will also be some cases where rendering algorithms need to be changed entirely to make best use of the larger color space and greater dynamic range. RTG for their part seems to be eager to work with developers through their dev relations program to give them the tools they need (such as HDR tonemapping) to do just that.

Wrapping things up, RTG expects that we’ll start to see HDR capable displays in the mass market in 2016. At this point in time there is some doubt over whether this will include PC displays right away, in which case there may be a transition period of “EDR” displays that offer 10bpc and better contrast ratios than traditional LCDs, but can’t hit the 1000+ nit brightness that HDR really asks for. Though regardless of the display situation, AMD expects to be rolling out their formal support for HDR in 2016.