"Aliasing" is a visual artifact caused by the limited spatial sampling of a resolved image. Often referred to as "jaggies," visual edges appear to shift sharply and not in a smooth gradient.
Aliasing impacts the Technical and Content Quality of the asset. Customer experience is negatively affected if on-screen visuals or elements are indiscernible due to aliasing. Typically, aliasing is not the creative intent, it is usually due to compression in file output. Any derivative of this video will contain the same (or worse) aliasing.
Aliasing occurs on far backgrounds, or matches the overall look of the content.
Aliasing occurs on all line edges of content on-screen.
How to Prevent:
Final file output must be re-rendered with a greater bit depth so that line edges do not exhibit aliasing.
We always recommend that you avoid re-sizing material where possible.
If there is an inescapable need to perform a slight resize of the content then ensure you are using a good quality re-size filter. Your transcoder should offer a few different re-size filters, each with their own advantages and disadvantages.
While some filters are better than others it is recommended that you test the material and review the results prior to processing a full piece of content.
There are times when deinterlacing of material is required. When deinterlacing material, review the options offered in your transcoder. Most will include a number of filters or modes for processing content (motion-compensated, motion-adaptive etc). Again, testing a small piece of the content and reviewing the results prior to processing a full piece is recommended. Always avoid any option listed as "simple" or "discard fields" as these will produce poor results.