Mali-V76: Enabling Efficient UHD 8k60 Content

Back in March 2018 we brought you Mali-V52, the video processor of choice for Mainstream and Ultra-Efficient solutions. Now it’s time to introduce Mali-V76, the latest and greatest premium VPU designed to bring next generation visual experiences, including 8K, to premium smartphones, DTVs and many other devices. 

8k on the horizon

Even in premium devices, 4K is still not the norm, so why (I hear you ask) would we already be targeting 8K? Simple. The industry rarely sits still and we, as IP providers, have to be ready for the requirements devices might have as far ahead as two years time. Coincidentally, two years time, in 2020, is when Japan is due to host the Olympics. Their big promise? Full 8K coverage. So, devices powered by the Mali-V76 video processor will be ahead of the curve in delivering that premium visual experience straight to the viewer, ensuring you see every stroke, lap or hurdle in stunning Super High Vision (SHV). Not only that, but Mali-V76 delivers this 8K decode up to 60fps, so fast that you need never miss a moment of your favourite events due to lag or poor framerate.

So how did we do this?

Well, an 8K60 stream needs 4x the bandwidth of a 4K60 stream, so by adding an extra AXI bus, we doubled the throughput capability on one side. We also doubled the line buffers from 4096 to 8192 throughout the video pipeline. A line buffer literally handles a line of pixels, so as you might assume, an 8K line is twice the width of a 4K one, delivering the extra boost.

It doesn’t stop there though, for the first time Mali-V76 is also able to handle 8K encode, though only at 30fps at this stage as anything greater really is a little ahead of its time… for now.

Of course, not all content providers have quite reached 8K, or are planning to in the immediate future, but Mali-V76 still provides a massive benefit compared to Mali-V61, its premium predecessor. As an alternative to one 8K stream, you could instead support four 4K streams at 60fps, meaning your favourite content providers like Netflix and Amazon can provide their customers with high quality, rolling previews of up to four different shows at once, saving the user valuable decision-making time in today’s always-on world. With lower resolution content, you can show an even greater variety of viewing options with up to 16 streams running in the still very impressive Full HD. This ability to support a 4x4 video wall is increasingly becoming an absolute essential in the Chinese market, as they strive to provide ever greater choice to us, the consumer.

Mali-V76 video processor

Whilst all these optimisations may sound simple, you might assume the majority come in the hardware itself, but in actual fact, one of Arm’s key strengths in this market is our somewhat unique approach.

Not just hardware

One of our advantages has always been the seamless integration of firmware and hardware. For those of you unfamiliar with the term, firmware is the kind of ‘happy medium’ of the ‘ware’ world. It’s the layer that dictates how the software controls the hardware, or the method of programming the cores themselves, and is a key differentiator for Arm that we talked about back with the Mali-V61. Since then, we have continued to make firmware improvements so significant that they even bring benefits to existing IP. Mali-V76 achieves a whopping 25% improvement on encode quality compared to Mali-V61, but even more exciting is that these firmware improvements have brought an additional 5% when compared to the Mali-V52 mainstream VPU, and that’s only been on the market for a few months! Of course, our clever engineers are never content, and are busy working away to provide even greater optimisations and improvements throughout 2018 and beyond.

What does Arm deliver to licensees?

Blink and you won't miss it!

My favourite innovation in the Mali-V76 though, I call Blink Removal, which is so clever it brings a whole new level of visual clarity, so I’m going to try and explain it in the best way I can.

As data is streamed into the display pipeline it moves through a display processor like the premium Mali-D71 and into the Assertive Display processor. Arm’s Assertive Display 5 then reads the characteristics of the previously handled frame and applies any necessary fixes to the next frame. Of course, one frame passes in the blink of an eye (you’re starting to see why we nicknamed it, aren’t you?), but even in such a brief moment, the human eye and brain can detect inconsistencies. So, at the end of a movie, if it switches to the black-screen credits or from a bright and sunny outdoor scene, for example, the visual balance is momentarily wrong. The eye will interpret this one frame delay the Assertive Display processor takes to figure it out as a tiny flicker, small but perceptible. 

However, in communications between Mali-V76 and Mali-D71, a huge number of statistics are gathered through the decoding process, and these statistics are very similar to those used by Assertive Display 5 to establish what it needs to change. To make the most effective use of this similarity, we’ve created a link in Mali-V76 that will feed into Mali-D71 and provide those stats at the same time it provides the frame itself. This means Assertive Display 5 no longer needs to redo the work and can instead apply the knowledge directly to the very same frame. Even at 60 or 120fps, this smooths out many visual artefacts you may not even have been aware of, raising the visual quality beyond even the bounds of resolution and framerate improvements.

Mali system advantages

You can see why the tight integration of Arm IP across the entire Mali Multimedia Suite of graphics, video and display brings real-world benefits to everyone from SIPs to OEMs, content providers to the end user. Arm’s innovative solutions focus ensures the very best visual experience across a whole host of device types and tiers.

Learn more about Mali-V76

Anonymous
Graphics & Multimedia blog