The rendering speed depends on a number of factors.
The design of a video editing program’s plugin interface may either allow high-speed processing by Mercalli, or it may restrict the speed. For instance, you can currently render/analyse a DV sequence (720×576) on a Pentium4 (Duocore) processor at 120 frames per second – provided you are using Canopus Edius. Other video editing programs may allow the processing of a maximum of 35 frames per second, even though only a small part of the processor capacity is used. Such an interface has clearly not been optimised to perfection.
The dimensions of a video signal are also crucial in assessing the rendering speed. For instance, an SD/DV signal with a resolution of 720×576 can be rendered about five times faster than a comparable HDTV signal with 1920×1080 pixels. This is to be expected, because HDTV simply contains five times as much data that need to be taken into account. Another factor can be use of a codec, which is always a “bottleneck” for data flows and subsequent processing.
For the sake of completeness, other factors that affect rendering should also be mentioned: the CPU used, the available RAM (the more there is, the better), and the bus system, which must be not be too small for the other hardware components. But this concerns all processing-intensive programs that also move large amounts of data within the memory – which includes the video editing program itself.