There's more to a phone than individual specs.
If you're looking to make sure your next phone can handle Google Daydream, you may have a list of things to expect from a phone. Google's documentation for Daydream is complex, but the essentials boil down to being able to handle a pair of 60fps streams and a very low latency and persistence rate. This means the phone can display VR without jittery images, without motion blur that could potentially disorient you.
Not all of these rules are set in stone, especially when it comes to things like display technology and processor architecture. With the latest batch of Daydream-ready phones, Google VR created exceptions for the Kirin processors as well as displays that appear to meet the bare minimum of what it takes for a quality Daydream experience. We sat down with Amit Singh, the VP of Business and Operations for Google VR, to learn a little more about what it takes to make a phone Daydream-Ready.
"In the end, if we can reduce the motion to photon latency into the 22ms-25ms range, you won't perceive that effect where there's lag. You could do it at any level of the stack. you could do it in hardware, you could do it at the sensor, and you could do it at the display. Each of them has friction. We can optimize, and today the path to optimization has lead us to the spec we have today, but everything is changing so fast in this world that other options quickly become available."
That doesn't mean every phone can be Daydream ready, even if the manufacturer wishes it so.
A big part of Singh's explanation comes from the recent addition of phones that don't have a Snapdragon 821 processor or the same kind of display as a Google Pixel. Google's flagship smartphone and the Moto Z seemed to offer a reasonable template for what kind of phone was required to support Daydream, but what it really comes down to right now is whether the manufacturer is willing to cooperate and optimize support to Daydream. Those changes may be fairly small, as was seen in the Moto Z, or it could be an entirely unique processor like the one in Huawei's Mate 9 Pro and Mate Porsche Design.
That doesn't mean every phone can be Daydream ready even if the manufacturer wishes it so. For example, the Huawei Mate 9 will be sitting on the sidelines while the Mate 9 Pro gains Daydream support. The biggest reason for this, according to Singh, is the display. "The combination of performance needs a few things in the stack. The right GPU, Android N and above, and OLED display. There are others, but you need that spec for high performance. If you don't, your latency is high enough that you'll notice it, and that immersion is broken and that's not a good experience. We're working with Huawei and other to see if there are solutions outside of OLED that would work."
Display resolution isn't currently as big a deal as you'd think, either. Google has now certified multiple 1080p phones for Daydream, though in their spec it's clearly listed that Quad HD or higher is recommended. Singh maintains these lower resolution displays don't break the immersive experience Daydream is going for if well tuned. "It's really still a tuning art. It's the combination of the sensor, the display, the optimizations, all together with the content. That's why we're certifying each phone as its own thing, and we're delighted to have those phones."
So how will you know if your next phone is going to be Daydream-ready? Ideally, this spec will be part of the announcement, so you'll know before it is even available for you to purchase. The most notable exceptions to this will be if a phone is updated to Android N later, and becomes available for certification at that stage. That doesn't mean every Android N phone will be ready for Google Daydream, especially if that phone offers a competing VR platform - but it's clear Google's goal right now is to help their partners and quickly grow the list of supported devices.