In Multimedia Trust preferences, you can specify whether to play embedded multimedia files in trusted or nontrusted PDF documents. A trusted document is a document that you or an author you trust has approved. By setting your permissions to play multimedia only in trusted documents, you can prevent programs, macros, and viruses from potentially damaging your computer.

The list of trusted documents and authors is stored internally and can’t be viewed. If you add a certified document to the list, both the document and the certificate of the author are added to the list of trusted documents. All documents that this author certified are trusted. (Trusted documents also include PDFs from authors in your list of trusted identities.)

In the Preferences dialog box, select Multimedia Trust (Legacy) from the Categories.

Display Permissions For

Choose to set permissions for either trusted documents or other (nontrusted) documents.

Allow Multimedia Operations

Select this option to allow media clips to be played. When selected, you can change the permission settings for a particular player and enable options that determine the appearance of the media during playback.

Change Permission For Selected Multimedia Player To

Select the player from the list, and then choose one of the following options from the menu:

Always

Allows the player to be used without prompting.

Never

Prevents the player from being used.

Prompt

Asks the user whether the player can be used. If you select this option and allow the player to play the media in a particular document, that document becomes trusted.

Allow Playback Options

Three playback options enable you to control how the video is displayed.

Allow Playback In A Floating Window With No Title Bars

Select this option to run the video without a title bar. The result is that no title or close buttons are displayed.

Allow Document To Set Title Text In A Floating Playback Window

Select this option to display a title bar when the video plays back in a floating window. To edit the text in the title bar, double-click the video with the Select Object Tool (Tools > Advanced Editing > Select Object Tool). Select Edit Rendition, and then on the Playback Location tab, select Show Title Bar. Add the title bar text in the Title text field.

Allow Playback In Full-Screen Window

This option automatically plays the video in full screen mode when it is played back. Full screen display can conflict with end-user security settings.

Clear Your List Of Trusted Documents

Deletes the current list of trusted documents and authors. Use this option to prevent media from playing in documents that were previously trusted documents or created by trusted authors. This option is available only when a PDF that contains multimedia is open.