HMP Software

astr_brdThe viability of host-based software in providing media processing capabilities continues to expand the possibilities for voice application development. Over time, we will see a larger percentage of applications deployed on host vs. board-based systems. This trend is driven primarily by the relentless increase in processor speed and capabilities. Host-based media processing is also a natural fit for VOIP-based applications, since these applications can now be delivered as software-only solutions.

Vendors of host-based media processing implementations face a number of technical challenges in providing a viable solution to telephony application developers. The main challenges are:

Key Features

1. System Capacity: optimizing media processing algorithms to take advantage of the computing power now available on standard desktop platforms. 
2. Robustness: preventing other applications running on the platform and the media processing from interfering with each other when competing for CPU resources. 
3. Latency: ensuring that the latency introduced by the media processing does not affect the perceived quality of the audio signal being processed.

Defining System Capacity

The capacity of a system is the maximum number of active media processing channels (such as play, record, DTMF detection, and echo cancellation) that can be supported by the application on a platform. The greater the capacity of a single platform, the lower the cost per port for an application, and the greater the value the application provides to a customer. To increase the capacity of an application, the media processing must be as efficient as possible.

The factors that affect the system capacity of host-based media processing applications on a platform are:

• The acceptable percentage of CPU capacity that can be dedicated to media processing.
• The types of media processing that are performed on each active channel. 
• The specifications (CPU speed and architecture, operating system, amount of RAM, cache size, and NIC speed) of the platform running the application.

PIKA has performed extensive performance tests with a variety of media processing applications executed on a wide range of platform configurations. Figure 1 lists a representative sample of applications that PIKA has benchmarked and the media processing that was performed on each channel for the duration of the test.