How Do I Compress a Quicktime Movie?

by K.C. Winslow

Quicktime movies can be compressed to a smaller file size using Quicktime Pro. The Quicktime Pro application is a movie viewer and converter that allows users to input custom settings before exporting a new version of a movie file. The Quicktime Pro application is a part of the Snow Leopard operating system and is also available for purchase.

Preparing to Compress

After opening the movie file you want to compress in Quicktime Pro, go to the File menu and select Export. Enter the title you want to use for the compressed movie as well as the location where it should be saved. Set the Export pull-down menu to Movie to Quicktime Movie. Press the Options button to open the Movie Settings window. Press Settings under Video in the Movie Settings window to access the video compression settings.

Selecting the Codec

The pull-down menu at the top of the Standard Video Compression Settings window allows you to select the codec you will use to compress the video. A codec is a specific method of encoding information. For the highest quality video with the lowest file size, the H.264 codec is recommended.

Choosing the Frame Rate

The number of images shown per second in a video is known as the frame rate. For high-quality video, the frame rate should be left as Current. However, if quality loss is acceptable, you can lower the frame rate to decrease the size of the video file. This will lower the number of images that are shown per second.

Adjusting the Key Frames

Key frames are a way of compressing a movie file. The key frame is an image frame that contains all of the data in its original form. Subsequent frames contain only the data that is different from the key frame. The lower the key frame rate, the lower the size of the file and the lower the quality of the video. To adjust the key frame to the lowest possible rate without losing considerable quality, multiply the frame rate by five and enter that number in the key frame box.

Setting the Data Rate

The data rate is the speed at which the movie data is transferred. The higher the data rate, the higher the quality of the movie and the larger the file size. To restrict the data rate, click the "Restrict to" button and select a data rate from between 300 to 1,000.

Adjusting the Quality Setting

The quality setting cannot be adjusted if you have restricted the data rate. However, if you have left the data rate as Automatic, you can change the quality setting. The lower the video quality, the smaller the file will be.

Compressing the Video

After all of the settings have been entered, press Okay to exit the Compression Settings window and Okay to exit the Movie Settings window. Press Save to compress the Quicktime movie.

About the Author

A writer from Chicago, K.C. Winslow has been publishing articles relating to health, beauty, travel, crafts, education, Macintosh computers and technology since 2000. She holds a Master of Arts degree in writing from the University of Melbourne, Australia, where she lived for several years.

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