Final answer:
Anamorphic 1080p refers to a vertical resolution of 1080 pixels but can have varying horizontal resolutions after being stretched to match the intended aspect ratio, typically wider than 1920 pixels for a widescreen image.
Step-by-step explanation:
When you see the term '1080p' for anamorphic video, it commonly refers to the standard resolution for high-definition video, which is 1920 pixels horizontally and 1080 pixels vertically. Anamorphic video takes advantage of the widescreen aspect ratio without compromising the vertical resolution. However, with anamorphic footage, the video is actually recorded with a squeezed horizontal aspect, which later needs to be 'stretched' or 'unsqueezed' during post-production or playback to achieve the correct aspect ratio.
Anamorphic 1080p footage typically means that the footage has a vertically squeezed aspect ratio of 1080 lines of resolution, but the horizontal resolution can vary depending on the aspect ratio desired. For example, if the final display is intended to be 2.39:1 aspect ratio, the number of horizontal pixels will be higher than 1920 when unsqueezed to achieve the wider image.