Imagination announces PVRIC4 'visually lossless' compression IP

Imagination Technologies has announced a new standalone intellectual property (IP) block, to be integrated in its next-generation PowerVR graphics but not reliant upon it, which is claimed to offer considerable improvements in performance for memory- and bandwidth-constrained devices: PVRIC4 'visually lossless' compression.

Modern desktop graphics processors typically come with quantities of RAM that would have been near-unimaginable as primary system RAM just a decade or so ago. Less powerful devices, though, in particular system-on-chip (SoC) designs targeting embedded and low-power uses, have to do more with less - and that goes for both the quantity of memory available for graphics use and the bandwidth available for transferring data into and out of said memory.

That, Imagination claims, is where PVRIC4 comes in. Described by the company as a 'dual-pipeline frambuffer compression engine,' a PVRIC4 block attempts to compress content through a lossless compression system which is then swapped out for a lossy but 'visually lossless' system if 50 percent or greater compression ratios are not achieved. The result: 'The image quality change is imperceptible,' the company claims, but the memory and bandwidth needs are slashed in half - meaning manufacturers can reduce costs by reducing the RAM, or improve performance by freeing RAM and bandwidth for other purposes while the GPU is being driven hard by a game or video application.

'With the increasing demands introduced by higher resolution 4K and 8K displays as well as the desire to reduce system costs, the need to minimize memory bandwidth is an ongoing priority for our customers,' explains Nigel Leeder, executive vice president for PowerVR at Imagination, of the technology's inspiration. 'They require a solution that keeps costs and power down. By introducing visually lossless compression into our GPUs, we can now guarantee a reduction in memory bandwidth and usage.'

PVRIC4 can be used with alongside other compression technologies including glTF Draco and VESA Display Compression-M (VDC-M) to reduce bandwidth requirements in other areas of the media display pipeline.

While PVRIC4's first outing will be in Imagination's own PowerVR graphics processing products, it's not exclusive to them: The company is making the PVRIC4 core available as an independently licensable block, meaning that it's possible for other GPU vendors to integrate the technology into their own, competing parts. Thus far, though, the company has not confirmed any customers for the IP.