Watching Streaming QuickTime Media

QuickTime 4.0 introduced a new technology to the world of QuickTime — streaming media. QuickTime 6, the version included with Mac OS X 10.3, has significantly improved the performance of streaming media. With streaming media, QuickTime movie files (whether they contain video, audio, text, or other elements) are sent over the Internet a piece at a time. Those pieces are reassembled in QuickTime Player and played back almost as quickly as the data arrives over the Internet. In this way, movies can be viewed (or listened to) more quickly over the Internet. Likewise, live events can be displayed in real time over the Web.

Tip

For optimum streaming, QuickTime Player consults the settings on the Connection tab in your QuickTime System Preferences. Make sure these settings match the speed of your connection so that you get better playback from streaming movies.

With some streaming media movies, you can pause, play, and move back and forth within the movie file by using the play bar or the forward and reverse controls. In others, especially live events, you won’t have as much control — pausing and playing again takes you to the current moment in the live event instead of picking up where you left off.

QuickTime streaming media uses an Internet protocol known as RTP (real-time transport protocol). RTP is similar to the familiar HTTP protocol used for Web pages, but RTP is designed specifically for the special requirements of streaming media. With RTP, movies are not downloaded to your computer. Instead a continuous data stream is sent to your computer, and QuickTime plays it immediately.

QuickTime movies can also be sent to your computer via the HTTP or FTP protocols. With HTTP or FTP, the entire movie is downloaded to your computer. (If you don’t have QuickTime Pro, the movie may be downloaded to a temporary file that is deleted automatically.) You don’t necessarily have to wait for the entire movie to finish downloading before it begins playing. Many QuickTime movies use a technology called fast start or progressive download. In practice, fast-start movies may seem like streaming video. In fact, QuickTime begins playing the first part of the movie while it continues to download the remainder.