Videodub and aspect ratio

We do a lot of video processing work and find that whilst a good number of free, Open Source or low cost tools exist for converting between different video formats, most of these do not 'understand' the needs of television as they are optimised for comuter display use.

Now one of the important aspects - to use a terrible pun - of television is the 'aspect ratio' - the ratio of width to height. This is expressed as 4x3 or 16x9 and leads to all sorts of problems when trying to display cinema film on telesions - letterboxes anyone? - or perhaps 'pan & scan'...

One also needs to be aware of the pixel size ratio - are you working with square pixels or recatangular ones?

One software firm that does understand this problem is Aimersoft. Their software correctly allows for 16:9 and other cropping formets and works well. But it is not free, costing around $70-$100.

VirtualDub, on the other hand, is less 'glossy' but is Open Source (& so 'free') and can be persuaded to understand aspect ratios.

1.Launch VirtualDub -> File -> Open video file -> browse to and highlight the AVI -> Open.
2.Video -> Compression -> choose your favorite codec (in this example we will use DivX Pro v6.8).
3.Take note if the codec has format restrictions--e.g., with DivX, the screen size must be a multiple of 4.
4.Configure -> check "Use presets to configure the encoder" -> set to highest quality -> keep original bitrate.
5.OK -> OK.
6.Video -> Filters -> Add -> Resize -> OK.
7.In "Size options" section, check "Aspect ratio" option of "Compute height...". NOTE: In our example, we will correct a movie wherein the figures appear squeezed (e.g., narrowed faces), such as when aspect ratio is 3:2 (1.50:1) but should be 37:20 (1.85:1)--i.e., 720x480 should be 720x390.
8.In the "Compute height from ratio" boxes, type in 37:20.
9.Adjust "Codec-friendly sizing" if required by the codec you choose to recompress the file in step 9.
10.Press "Show preview" button -> Hold down Shift key and drag progress controller to the right to view change.
11.Exit preview window when done.
12.OK -> OK.
13.Video -> Full reprocessing.
14.File -> Save as AVI -> browse to save location -> Save. NOTE: Right-click anywhere in screen to zoom in or out. NOTE: Minimize VirtualDub to speed up process (screen will not need to be refreshed constantly).
Not my work, but found here.