Interpret footage items



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:

Important: In all of these cases, the information is used to make decisions about how to interpret data in the imported footage item—to tell After Effects about the input footage. The interpretation settings in the Interpret Footage dialog box should match the settings used to create the source footage file. Do not use the interpretation settings to try to specify settings for your final rendered output.

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 step is usually only necessary when the footage item does not contain an embedded color profile.

When you preview in the Footage panel, you see the results of the footage interpretation operations.

Jeff Almasol provides a script on his redefinery website that you can use to make guessing the 3:2 pulldown, 24Pa pulldown, or alpha channel interpretation more convenient.

Interpret a single footage item using the Interpret Footage dialog box

 Select a footage item in the Project panel and do one of the following:

  • Click the Interpret Footage button at the bottom of the Project panel.

  • Drag the footage item to the Interpret Footage button.

  • Choose File > Interpret Footage > Main.

  • Press Ctrl+Alt+G (Windows) or Command+Option+G (Mac OS).

Interpret a proxy using the Interpret Footage dialog box

 Select the original footage item in the Project panel and do one of the following:

  • Alt-click (Windows) or Option-click (Mac OS) the Interpret Footage button at the bottom of the Project panel.

  • Alt-drag (Windows) or Option-drag (Mac OS) the footage item to the Interpret Footage button.

  • Choose File > Interpret Footage > Proxy.

Apply Interpret Footage settings to multiple footage items

You can ensure that different footage items use the same settings by copying interpretation settings from one item and applying them to others.

  1. In the Project panel, select the item with the interpretation settings that you want to apply.
  2. Choose File > Interpret Footage > Remember Interpretation.
  3. Select one or more footage items in the Project panel.
  4. Choose File > Interpret Footage > Apply Interpretation.

Edit interpretation rules for all items of a specific kind

The interpretation rules file contains the rules that specify how After Effects interprets footage items. In most cases, you don’t need to customize the interpretation rules 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.

In most cases, the name of the interpretation rules file is interpretation rules.txt; however, some updates to After Effects install a new interpretation rules file with a name that indicates the updated version number, and the updated application uses this new file. If you’ve made changes to the old interpretation rules file, you may need to apply those changes to the new file, too.

Locations of the interpretation rules file:

  • (Windows XP and 32-bit Windows Vista) C:\Program Files\Adobe\Adobe After Effects CS4\Support Files\

  • (64-bit Windows Vista) C:\Program Files (x86)\Adobe\Adobe After Effects CS4\Support Files\

  • (Mac OS) Applications/Adobe After Effects CS4/

  1. Quit After Effects.
  2. As a precaution, make a backup copy of the interpretation rules file. By default, this file is in the same location as the After Effects application.
  3. Open the interpretation rules file in a text editor.
  4. Modify the settings according to the instructions in the file.
    Note: You must supply a four-character file-type code for each footage type or codec. If you don’t know the code for a file or codec in a project, press Alt (Windows) or Option (Mac OS) as you select the file in the Project panel. The file-type code and codec code (if the file is compressed) appear in the last line of the file description at the top of the Project panel.
  5. Save interpretation rules.txt.