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By Barb Roeder Creating an HREF Track HREF tracks are specialized text tracks containing URLs to other pages and sites as well. In this case, however, the text is not normally viewed; rather, it is used to synchronize your movie with other media at your site. For example, an online catalog might have a movie with product demonstrations, and for each segment a different frame, with product information displayed on the same Web page. In an HREF track, the text information can be updated without recreating the movie. HREF tracks can be clickable or autoloading. Figure 4 illustrates both methods in one text descriptor file, which was created using the following steps. 1. Start with a list of URLs in a plain text file and use the steps outlined above to create a basic text track movie. 2. After exporting the text descriptor file, you can open it up in your word processing application. Then, open the movie file and its information window in MoviePlayer, using the Get Info command in the Movie pull down menu. Your display should look like Figure 5.
Tip: Click on the button with four dots in MoviePlayer to reveal the playback controls that will help you scrub through your movie and find time codes. Move the black diamond in the MoviePlayer controller to the general point of the segment begin or end time, then use the middle set of keys on the controller (hi-lighted in gold in Figure 5), to step through single frames for complete accuracy. 3. The times listed in the text descriptor file shown in Figure 5 are the default two-second segments that QT assigns to each line of text (in this case, each URL). Choose the movie segments where you want these links to be active, then use the times listed in the Movie/Time information window under Current Time, to modify the time stamps in the text descriptor file. Always end the text descriptor file with a time stamp of the ending movie time, as listed in the Movie/Time Duration information block. Tip: A blank line, such as the one between the first two time stamps of the text descriptor file in Figure 5, can be used to deactivate the links as the movie progresses. 4. Edit the new text descriptor file
using the syntax shown in Figure 4. After the second time stamp in
the text descriptor file, an automatic link is created by proceeding
the URL with the A tag. The page for Product 1 then loads into the
Tip: Make your URL segments at least 1/2 a second long so they won't be skipped if QT has to drop some frames to keep up during playback on slower computers and/or connections. 5. Save the text descriptor file and import it into the player application. 6. Add the text movie back into your movie file using the Add Scaled command. Make sure the cursor is at the beginning of the movie file. Hold down the Shift-Ctrl-Alt keys (on Windows) or Shift-Option keys (on Mac) and pull down the Edit menu. The Paste command should be listed as Add Scaled. 7. Assign the text track to be an HREF track in the information window shown in Figure 6. When you click on the Change Name button in the General panel, the Change Track Name dialog box appears. Using the exact same format as shown in the figure, you name your text track HREFTrack. 8. Disable the HREFTrack so the URL text is not displayed in the movie frame using the Edit->Enable Tracks pop-up menu, then save the movie without dependencies. HREF tracks can be streamed, but it is a little tricky to time the downloading of the HTML for synchronization with your movie. An example of how to use the Sprite track feature of QT to accomplish this will be discussed in the next section.
待续。。。 |
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