Apple QuickTime 7 - Manual (Page 48)

48 Chapter 4 Exporting Files With QuickTime Pro
 Video Format: Choose the video compressor (codec) you want to use to compress
your video. For the highest quality at the lowest data rate (or the smallest file), H.264
is recommended. If you need the file to play on a device that supports MPEG-4 video,
choose MPEG-4 Basic or MPEG-4 Improved, depending on the target device. If your
source movie's video track is already compressed, you can choose “Pass through” so
that the video doesn’t get compressed again.
 Data Rate: The more kilobits per second (kbps), the better the movie quality. For
best playback, however, don’t choose a data rate higher than the available
bandwidth.
 Optimized for: If you choose H.264 from the Video Format pop-up menu, choose
your intended delivery method from the “Optimized for” pop-up menu. This setting
tells the codec how much the data rate can vary above and below the data rate you
choose.
 Image Size: Current maintains the source material size. To choose a size not listed in
the pop-up menu, choose Custom.
 Frame Rate: In most cases, your video will look better if you choose a number that is
exactly divisible by the FPS (frames per second) of your source. For example, if your
source is captured at 30 FPS, choose a frame rate of 10 or 15. Don’t choose a rate
larger than that of your source material.
 Key Frame: The more often you specify a key frame (the lower the number), the
better the video quality, but the bigger the file.
If you choose MP4 from the File Format pop-up menu and H.264 from the Video
Format pop-up menu, and then click Video Options, you get the following additional
options:
 Restrict Profile(s) to: If you need the file to play on a device that conforms to one or
more of the standard’s profiles, check those profiles here.
 Encoding Mode: Choose whether you want the best quality or faster encoding.
MPEG-4 Audio Export Options
When you export a movie to MPEG-4 format (by choosing File > Export and then
choosing “Movie to MPEG-4”), you access the following options by clicking Options and
then clicking Audio.
 Audio Format: Choose your audio compressor (codec) here. If your source movie has
only one audio track and it is already compressed, you can choose “Pass through” so
that the audio doesn’t get compressed again.
 Data Rate: As with video, the more kilobits per second, the better the audio quality.
 Channels: Choose between mono (1 channel) or stereo (2 channels).
 Output Sample Rate: Available only with AAC audio. It’s best to match the sample
rate to that of the target device.