With Shanghai done and dusted for 2017 it was a crawl through traffic and a dash through security and here we are in Beijing. Two uncharacteristically clear and sunny days in a row and spirits are high as we kick off the second China Tech Symposium.
One of my favourite things about doing the rounds of Arm’s Tech Symposia is the opportunity to catch up with some of our partners and understand how we’re working with them to provide better and better technologies and solutions. This week I’m in China and my attention has been grabbed by a really cool demo we’ve worked on with our friends at Hardent.
From a history of providing engineering services and technical training, it was just a couple of years ago that Hardent got into the IP space, joining the Video Electronics Standards Association (VESA) and becoming a founding member of the Display Stream Compression (DSC) task group. The first VESA DSC IP product Hardent brought to the market was a video encoder IP core in 2014 and they’ve since focussed on DSC IP, which is where we come in.
The clever folks at Hardent are always keen to collaborate for the good of the industry and have been working hard with our own display engineering teams to integrate their DSC with our brand-new display processor, Mali-D71, launched in Taiwan last week. The result of all this hard work is a demo showing Mali-D71 reading HDR video and performing composition of UI related graphical overlays, such as menus and pop ups, to produce the scene you’ll see on the final display. Assertive Display 5, also launched at the first Tech Symposium of the season, provides pixel by pixel tone mapping onto the display to ensure clean, crisp contrast, saturation and backlight control for the panel. After that, Hardent’s DSC block steps in as the content moves out of Mali-D71’s pipeline and into the high resolution display for viewing. The DSC block compresses the content to make sure you’re not using massive amounts of throughput that simply isn’t available. Compression has a tendency to be ‘lossy’, in terms of visual quality, so what’s really clever about Hardent’s solution isn’t that they’ve prevented that loss, but that they’ve hidden it. The complete information isn’t delivered to the panel, but the visually lossless result makes it look like it is. This reduces throughput by up to three times, but is totally programmable based on the customer’s requirements, allowing OEMs to target the exact sweet spot they’re hoping for. Though I knew the theory of this, I hadn’t quite understood how it was possible that the end result would look as good (ok fine, I was sceptical), but it really does. The demo shows the content running through with at least one overlay to show the composition for HDR and non HDR and features a toggle to switch the DSC on or off. Not only is there (astoundingly) no discernible difference to the naked eye, but it also provides a huge cost and power saving and can be performed on a single MIPI DSI link.
As we know, latency is another huge concern, especially in technologies like VR where 20ms is considered the maximum delay acceptable before the user’s experience is severely compromised. Yet another awesome benefit of this solution is that, in spite of running through a whole extra piece of IP in the pipeline, there is negligible latency (< 1 microsecond) added by the compression process and therefore no compromise to immersion quality.
The cost and latency savings are always super exciting to our partners but the real thrill is in the visual quality retention, everyone who passed by the stand was quick to grasp the implications of something that can reduce throughput so dramatically without reducing the quality experience of the end user. Not only that, but it works across all content types from Hollywood movies, to holiday snaps, to text graphics. For mobile panels, reducing the throughput on output (especially for 4K) has been practically impossible without serious quality loss and have therefore been limited to Full HD or WQHD, so this solution provides a huge opportunity for the future growth of 4K panels on mobile devices in a lower budget.