At first glance, measuring processor performance on multimedia applications can seem straightforward. Many multimedia applications are based on published standards and widely available software. For example, MPEG-4 video decompression software is available for most popular processors. Because such software is often readily available, measuring multimedia performance may seem to be a simple matter of checking the processor vendor's published performance data for the relevant software modules.
In reality, reliable measures of processors' multimedia performance are hard to obtain. A number of factors confound attempts to obtain meaningful, apples-to-apples performance comparisons. One of these is the data-dependent processing loads posed by many multimedia tasks. For example, the processing power required for MPEG-4 video decoding can vary by as much as a factor of two depending on the content of the video.
Further complicating matters, vendors may omit key application components from their performance quotes. For example, MPEG-4 video decoding is nearly always followed by color space conversion, but vendors rarely include color space conversion in their performance figures. This is a crucial omission, because color space conversion is computationally intensive. On an ARM9E running a typical MPEG-4 decoder at 176x144 pixels and 15 frames per second, for example, color space conversion requires roughly the same computation power as MPEG-4 decoding.
Navigating these complexities requires in-depth knowledge of multimedia applications, processors, and software. Thanks to its years of experience in each of these areas, BTDI has the expertise needed to obtain meaningful, comparable measures of processors' multimedia performance. In one recent project, BDTI compared processors for a variety of mobile multimedia applications. For each application, BDTI analyzed the performance requirements of the resource-intensive tasks such as video compression. BDTI used these requirements to evaluate the processors' multimedia processing capabilities, including the capabilities of their hard-wired multimedia accelerators.
BDTI is now making its multimedia performance evaluation expertise widely available through the new BDTI Video Benchmarks. To learn more about these benchmarks, visit http://www.BDTI.com/products/services_video_benchmark.html or contact Jeremy Giddings at giddings@BDTI.com.