Audio supercomputer hidden in your graphics card?

Cambridge (MA) - Nvidia's graphic cards may have much more to offer than simply drawing pixels on the screen: A startup company has found a way to translate audio signals into graphics, run them through the graphics card and overcome a common issue of limited audio effect processing performance in computers.

It is not unusual that professional music artists run into performance barriers even with the most powerful computers today. Multi-track recording still is a challenging and sometimes frustrating task. James Cann from BionicFX in Massachusetts however noticed that audio processing task does not have to happen just in the CPU. His Audio Video Exchange technology (AVEX) converts digital audio in graphics data and then performs effect calculations using the 3D architecture of Nvidia GPUs. Compared to the capability of just six GFlops of a typical CPU, Nvidia's chips can reach more than 40 GFlops, according to Cann.

"This technology allows music hobbyists and professional artists to run studio quality audio effects at high sample rates on their desktop computer," he said. Cann's invention is purely software-based and is not capable substituting a sound chip. The approach exploits the video card 3D chip, which usually is idle when users are working with multi-track recording software. "It's a great resource to use as a coprocessor," Cann said. "AVEX is designed to reduce the CPU load by moving the processing to the video card for certain types of audio effects when making music." Cann said that the technology is purely targeted at music enthusiasts and at this time brings no advantages for applications such as gaming.

But if Cann is right, audio effect processing might be just a starting point how a GPU could be used for other applications. He believes that several other software types could be greatly enhanced in the same way, such as Genomics or SETI. "The GPU has some numeric precision issues that need to be worked out for scientific applications to be possible, but the thought of performing the computations on a resource theoretically capable of 50 and more GFlops of the GPU instead of five GFlops of the CPU is exciting," he said.

So far Cann cannot take as much performance away from the GPU as he would like. "Right now, getting the data back from the video card is very slow, so the overall performance isn't even close to the theoretical max of the card. I am hoping that the PCI Express architecture will resolve this. This will mean more instances of effects running at higher sample rates," he said.

Still, there is significant boost of performance and reduce the load for CPU for people who are using applications such as Cubase, Ableton Live, and other VST compatible hosts. Cann's first commercial application will be BionicReverb, which is expected to go into public and free beta in October. The final version is scheduled to be released at the Winter NAMM Conference in January 2005.

BionicReverb is an impulse response reverberation effect that runs as a plug-in inside VST compatible multi-track recording software. The audio effect is generated by combining an impulse response file with digital audio. Impulse response files are created by firing a starter pistol inside a location, such as Carnegie Hall, and recording the echoing sound waves. Combining the two files through mathematical convolution is a CPU intensive process that is reduced by moving expensive calculations onto the GPU. Amateur and professional guitarists, singers, pianists, and other musicians will be able to create performances in their home or studio that sound exactly like they were recorded in famous locations around the world, according to Cann.

At this time, Cann plans to only support Nvidia graphics cards. "When I started, ATI had a problem with floating point data. I have heard they have resolved it, but I won't have time to purchase and research their newest cards until after this is released," he said.

Pricing was not announced yet, but Cann says he will make his technology available for "far less" than the cost of professional studio DSP solutions which can run into the high five-figure range. He estimates the price will be somewhere between $200-$800.