More Details on Elemental's GPU Accelerated H.264 Encoder

The Deal with BadaBOOM

Due out in Q3, BadaBOOM is going to be the consumer version of the encoder. It will be an "affordable" program designed for those users who want to quickly take a video file and convert it to another format without playing with settings like bitrate. This is the application we were given a chance to preview.

Under the RapiHD brand, Elemental will deliver a professional version of their encoder/transcoding software. This application will allow you more options than BadaBOOM, letting you select bitrate and resolution, among other quality settings, manually.

As we mentioned before, the software was developed using CUDA and thus will only run on a CUDA-enabled NVIDIA GPU. NVIDIA has a full list here but in short, anything from the GeForce 8, GeForce 9 or GeForce GTX 280/260 families will work.

Mr. Blackman told us that the company isn't specifically tied to using NVIDIA hardware and that as Larrabee and other AMD/ATI solutions come to light it may evaluate bringing the technology to more platforms. But for now, this will only work if you have a CUDA-enabled GPU (and as such, it stands to be one of the biggest non-gaming killer apps for NVIDIA hardware).

Performance

In our testing we found that even though performance improved tremendously over a CPU-only encode, the process still required a fast host CPU (the Core 2 Extreme QX9770 was at 25 - 30% CPU utilization). It turns out that there are two factors at work here.

According to Mr. Blackman, NVIDIA's initial CUDA release didn't have the streaming mechanism that allows you to run CPU cycles in parallel with the GPU. This functionality was added in later versions of CUDA, but the early beta we tested was developed using the initial CUDA release. Once the CPU and GPU can be doing work in parallel, the CPU side of the equation should be reduced.

Secondly, it's worth pointing out that only parts of the codec are very parallelizable (motion compensation, motion estimation, DCT and iDCT) but other parts of the pipeline (syntax decoding, variable length coding, CABAC) are not so well suited for NVIDIA's array of Streaming Processors.

Elemental also indicated that performance scales linearly with the number of SPs in the GPU, so presumably the GeForce GTX 280 should be nearly 90% faster (at least at the GPU-accelerated functions) than a GeForce 9800 GTX.

SLI Support?

As we found in our GT200 article, in most cases NVIDIA's fastest GPU is actually the pair of G92s found on a single GeForce 9800 GX2. Unfortunately, Elemental's software will not split up a single video stream for processing across multiple GPUs - so NVIDIA's fastest GPU would be the GeForce GTX 280.

There is an exception however; if you do have multiple GPUs in your system, the professional version of Elemental's software will let you output to two different resolution/bitrate targets at the same time - with each GPU handling a different transcode stream.

Final Words

We've still got a couple of months before Elemental's software makes its official debut, but it's honestly the most exciting non-gaming application we've seen for NVIDIA's hardware.

We have already given Elemental some feedback as to features we'd like to see in the final version of the software (including support for .m2ts and .evo files as well as .mkv input/output). If there's anything you'd like to see, leave it in the comments and we'll pass along the thread to Elemental.

Elemental's software, if it truly performs the way we've seen here, has the potential to be a disruptive force in both the GPU and CPU industries. On the GPU side it would give NVIDIA hardware a significant advantage over AMD's GPUs, and on the CPU side it would upset the balance between NVIDIA and Intel. Video encoding has historically been an area where Intel's CPUs have done very well, but if the fastest video encoder ends up being a NVIDIA GPU - it could mean that video encoding performance would be microprocessor agnostic, you'd just need a good NVIDIA GPU.

If you're wondering why Intel is trying to launch Larrabee next year, this is as good of a consumer example as you're going to get.