After Effects uses a set of internal rules to interpret each footage item that you import according to its best guess for the source file’s pixel aspect ratio, frame rate, color profile, and alpha channel type. If After Effects guesses wrong, or if you want to use the footage differently, you can modify these rules for all footage items of a particular kind by editing the interpretation rules file (interpretation rules.txt), or you can modify the interpretation of a specific footage item using the Interpret Footage dialog box.
The interpretation settings tell After Effects the following about each footage item:
How to interpret the alpha channel’s interaction with other channels. (See Specify alpha channel interpretation.)
What frame rate to assume for the footage item. (See Change frame rate.)
Whether to separate fields and, if so, what field order to assume. (See Separate video fields and Determine the original field order.)
Whether to remove 3:2 or 24Pa pulldown. (See Remove 3:2 or 24Pa pulldown from video.)
The pixel aspect ratio of the footage item. (See Change pixel aspect ratio.)
The color profile of the footage item. (See Interpret a footage item by assigning an input color profile.)
Generally, you don’t need to change interpretation settings. However, if a footage item isn’t of a common kind, After Effects may need additional information from you to interpret it correctly.
You can use the controls in the Color Management section of the Interpret Footage dialog box to tell After Effects how to interpret the color information in a footage item. This is usually only necessary when the footage item does not contain an embedded color profile.
Interpret a single footage item using the Interpret Footage dialog box
Apply Interpret Footage settings to multiple footage itemsYou can ensure that different footage items use the same settings by copying interpretation settings from one item and applying them to others.
Edit interpretation rules for all items of a specific kindThe interpretation rules file (interpretation rules.txt) contains the rules that specify how After Effects interprets footage items. In most cases, you won’t need to customize this file. When you import a footage item, After Effects looks for a match in the interpretation rules file, and then determines interpretation settings for the footage item. You can override these settings after importing, using the Interpret Footage dialog box.