Video engineers have been studying the process of optimal image display on screen, but the best method used often depends on the source material.

The most common artifact is often detected when there is motion in the image, seen as jagged edges on diagonal lines. There are two distinct types of formats available today on DVD disks.

Video - Derived from video sources which are captured as interlaced images at 30 frames per second.  This is the source often used for television studio cameras and hand held camcorders. 

Film - Derived from 24 frames per second sources, which must be converted to 30 frames per second, using a technique called 3:2 pulldown, or converting the  24 fps. material into 30 fps.

MPEG-2 decoders in the PC uses two different methods for decoding these distinct sources, BOB and WEAVE.  BOB is used to line double video sources, while WEAVE is used to re-create original film frame.  The HTPC is exceptional with the WEAVE method due to it's use of buffering prior to it's output, and it's use of refreshing the image at specific intervals. 

The refreshing or optimally using the vertical frequency for 24fps. sources is done in a reverse telecine method by using WEAVE and displaying the resulting image specific times, the simplest illustrated below:

24fps. shown 3 times = 72Hz
24fps. shown 4 times = 96Hz
24fps. shown 5 times = 120Hz

Bear in mind that not many displays can refresh faster than 60Hz which is typical in most consumer digital TVs.  The higher refresh rate pays off with high-performance displays such as Presentation Monitors and Front Projectors. 

The other benefit of a being able to obtain full original frame from source is the ease of interpolating the sampled image at higher resolution, area where the HTPC excels.  Using the same type of interpolating done in image editing programs such as PhotoShop, the DVD information is upconverted with perfection to a higher resolution video, ideal for displaying to a big screen and digital displays (LCD, DLP, D-ILA) requiring pixel perfect resolution for optimal image presentation.

The advent of the High-Definition TV has given the videophile the minimum requirement for higher-frequency image.  The ability to mimic a PC's 640x480 (480p) as well as the equivalent of 960x540 (1080i) resolutions provides the ability capability of connecting the HTPC to today's Digital TVs.