ATI have long since been touted as the leader in video playback quality in the video cores; VPE is nVIDIA's response to those claims in what they hope will surpass ATI in terms of quality.
The first element of VPE is full hardware MPEG2 decoding, which includes inverse quantization (IQ), inverse discrete cosine transform (IDCT), motion compensation, colour space conversion (CSC) functions, and hardware subpicture alpha blending.
Another part of VPE is Advanced Adaptive De-interlacing. Generally content made for display on a television is interlaced, and this is not desirable for progressive scan outputs such as PC displays, so it is necessary to de-interlace the source before output on a PC display. There are two methods for de-interlacing, 'Bob' and 'Weave'; each are desirable and undesirable in different situations. The VPE analyses each pixel and picks the best of the two methods to attempt reproduce the best de-interlace image quality possible.
VPE also features Advanced 5 Horizontal x 3 Vertical Taps Scaling & Filtering. Some high definition formats can come in at a resolution as high as 1920x1080, whereas most PC displays highest resolutions are 1600x1200 or even 1280x1024; the scaling and filtering is necessary to make sure that translation from the input resolution to the output resolution is as smooth as possible.
Independent Hardware Color Enhancements and Digital Vibrance Control is used to make sure the the gamma and colour is correct for the relevant input and display mechanism. Sources design for Television can sometimes look darker on a computer display and VPE's hardware control enables the user to alter the video gamma without altering the display of other applications. Digital Vibrance Control allows the user to set the display characteristics individually to each display attached to the computer.
VPE supports HD Component Output by integrating a 1024x768 TV encoder chip. To convert a computers RGB display into the TV broadcast format (YPrPb) three elements are required: a master sync generator to control the sync levels, an interlacer to output 480i and 1080i interlaced modes and a TV encoder, which operates in digital-to-analogue converter (DAC) mode with tri-level sync. VPE supports the first two of these element and all that is required to ship a graphics board capable of YPrPb output is a TV encoder that supports tri-level sync, and to replace the 4-Pin S-Video connector with a 9 pin.
Note that the VPE is currently only supported on the GeForce4 MX range of cards, the high end Ti cards do not feature it.
nView basically consists of two 350Mhz RAMDACS, each capable of steering a display device be it a CRT (regular monitor), LCD (notebooks) or flatpanels (TMDS). Being capable to drive two display devices is one thing, making intelligent use of this functionality is another. To make sure that custommers can maximise the 2 display devices NVIDIA is introducing a Setup Wizard which allows the user to tweak all the dual display options to his needs.
Obviously the basic multi-display functionality of Win2K/XP is available. This includes "big desktop" (both screens merge into one large desktop, aka as Span Mode), and clone mode (display the same information on both screens, handy when something has to be shown to a larger audience).
One of the typical problems with multi-displays is the positioning of windows and dialog boxes. Nothing is more annoying than a pop-up box appearing in the wrong display device forcing the user to exercise large mouse movements to click the options. nView solves this by either displaying the dialog box split on both diplays (half on both, reducing the potentail mouse movement) or always on the second display or in the display that contains the main application or always in the view that conatins the mouse pointer.
nView also allow the user to create individual desktops customised for specific tasks, the user can simply switch between these different desktops using short cut keys and thus access the functionality as efficiently as possible.
nView gives the user options for transparency effects for the windows and menus, rather than having opaque windows it might be useful to be able to see what one application is doing while copying some files around in explorer menus. Transparency allows more information to be present on the screen at the same time which can increase the efficiency of the user... but obviously it might hurt the readability of the contents.
Another interesting option is "zoom". In this mode the second display shows an enlarged, zoomed, part of the primary display. This can be handy for precision work in editing programs.
In short nView does not only offer you two displays, it also offers a full set of software tools to make optimal use of them.