The First Inklings Of Fusion: On-Die Video Decoding Via UVD3
Equipped with a modest 80 stream processors, graphics performance will never be Zacate’s flagship feature. However, the addition of AMD’s UVD 3 fixed-function decoding block makes it possible to watch high-bit rate content without taxing the lightweight Bobcat cores.
As mentioned previously, the UVD 3 we have here isn’t exactly like what you’d find on a Radeon HD 6000-series discrete board, though. On the downside, Multiview Video Coding is not accelerated, meaning you don’t get Blu-ray 3D support. That won’t be a deal-breaker for most, since Blu-ray 3D has been very slow to catch on in light of the expensive, battery-powered, heavy glasses required for each viewer. But it might become more of a detractor if the technology gains momentum in 2011.
However, the Zacate APU also introduces MPEG-2 hardware decode at the VLD (variable-length decoding) level. MPEG-2 is a fairly easy codec to decode, so nobody really gave it much thought that AMD wasn’t accelerating the entire pipeline (iDCT- and motion comp-only). And from a performance standpoint, the Brazos platform wouldn’t have had any problems. But by building in a more complete MPEG-2 decode solution, more of the workload is handled by efficient fixed-function logic, keeping the Bobcat cores as idle as possible, and extending battery life. Naturally, this is more of a consideration for mobile machines that will center on Brazos.
Of course, we wanted to double-check that AMD’s fixed-function logic was doing its share of the heavy-lifting, so we fired up Quantum of Solace (AVC) and The Book of Eli (VC-1) using a recently-optimized copy of CyberLink’s PowerDVD 10:
Though the Athlon II and Celeron see the lowest utilization numbers, remember that the Athlon II-based machine centers on AMD’s 880G chipset, which includes UVD 2 and is driven by a 2.8 GHz desktop processor, while the Celeron benefits from Nvidia’s Ion, armed with third-generation PureVideo.
The simple fact that AMD’s E-350 hovers around 20% utilization in H.264-based video and 30% utilization decoding VC-1 is pretty impressive. Also, these numbers include audio decoding, which happens on the CPU. If you were to bitstream Dolby TrueHD or DTS-HD Master Audio over HDMI, the two Bobcat cores would have even less work to do.
I spend some time talking about my findings with Louis Chen, CyberLink’s director of business development, who shared the performance numbers his technical team had recorded. Although we don’t have access to the single-core version of Zacate or either Ontario SKU, CyberLink says even the C-50 (Ontario, 1 GHz, single-core) should be capable of Blu-ray playback using any of the three accelerated codecs. You’ll see utilization in excess of 70% in H.264 titles, but the requisite performance is there.
