Video QA | Scan type

Advalidation can help you identify which type of scan is applied to your video. 

Progressive Scan

The Progressive scan type is a method of displaying, storing, or transmitting moving images. In a Progressive scan, the lines of each frame are drawn in sequence, one after the other. The Progressive scan type is often abbreviated as 'p' (e.g., 1080p) and is widely supported by digital devices such as high-definition televisions (HDTVs), computers, tablets and smartphones. 

Interlaced Scan

The Interlaced scan type is another method of displaying, storing, or transmitting moving images. In an Interlaced scan, the lines of a video frame are captured or displayed in two sequential fields called Upper Field and Lower Field (more info below).

This method was developed to reduce the bandwidth required for broadcasting and is often abbreviated as 'i' (e.g., 1080i). Interlaced is mostly supported on Televisions as it is the legacy standard for this device. 

Upper Field and Lower Field

Within interlaced scanning, each frame is subdivided into two field which are called the Upper Field and the Lower Field which are each made up of a different number of TV lines (example below for 1080i):

• the Upper Field is the set of odd-numbered lines (1, 3, 5,...,1079) - also called Top Field
• the Lower Field is the set of even-numbers lines (2, 4, 6,...,1080) - also called Bottom Field

A video is called Upper Field First or Top Field First (TFF) when the Upper Field is displayed first for each frame, followed by the Lower Field.

A video is called Lower Field First of Bottom Field First (BFF) when the Lower field is displayed first on each frame, followed by the Upper Field.

Advalidation's recommendation

This parameter entirely depends on what type of Scan you support as a publisher.

Happy validating!