QuickTime Player automatically determines your Internet connection speed. If movies you’re watching on the Internet don’t play properly, it may help to change the connection speed setting.

QuickTime tries to play versions of the movie authored for the match closest to the slower connection speed. If you choose a speed slower than your actual connection speed, the resulting movie may be smaller in size and lower in quality than your connection can actually support.

If you choose a speed faster than your actual connection, QuickTime playback may stutter or appear jerky because it is trying to deliver more data than your connection can support. Many movies, such as movie trailers, are downloaded instead of being streamed in real time. To get the best-quality movie available, set your speed to a higher connection speed and wait for the movie to download. If you do this, remember to change your speed back to the correct speed to receive real-time streaming movies at the proper rate.

If you’re unsure of your connection speed, check with your Internet service provider (ISP).

Note: If you change your connection speed and later want to make QuickTime automatically detect your speed again, choose Automatic from the Streaming Speed pop-up menu.

Instant-On dramatically reduces buffer (wait) time when you view streamed video. To use Instant-On, you must have a broadband connection. The responsiveness of Instant-On is affected by available bandwidth and the size, or data rate, of the content. It can also be affected by the codec used to compress the streaming video.

Instant-On is on by default. If you experience problems with streamed video, you can turn it off (deselect the checkbox) or change the wait time by dragging the Play slider.

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