Preview presets

When you use the Build Preview Movies command low resolution preview movies are created from your source movies to use even when the original source media is offline.

The following compression presets are available. The approximate file size for one hour of preview footage at 160x120 resolution is shown in each case. (In the Professional Edition you also have a full frame rate Offline RT preset, and can create your own customised preview settings using any available QuickTime compressor.)

Balanced
Video: Sorenson 3, 8 fps, medium quality. Audio: Qualcomm PureVoice 22kHz. (110 MB/hr)
Speed
Video: Motion JPEG, 6 fps, low quality. Audio: IMA 4:1 11kHz. (110 MB/hr)
Quality
Video: Sorenson, 12.5 fps, medium quality. Audio: QDesign Music 22KHz. (140 MB/hr)
Speed + Quality
Video: Motion JPEG, 8 fps, medium quality. Audio: IMA 4:1 22kHz. (250 MB/hr)
File Size
Video: Sorenson, 6 fps, low quality. Audio: QDesign Music 22kHz. (30 MB/hr)
Speed + File Size
Video: Motion JPEG, 5 fps, least quality. Audio: IMA 4:1 11kHz. (80 MB/hr)
Quality + File Size
Video: Sorenson, 8 fps, medium/low quality. Audio: QDesign Music 22kHz. (75 MB/hr)
Balanced (fast)
Video: Motion JPEG, 8 fps, low quality. Audio: QDesign Music 11kHz. (125 MB/hr)
MPEG-4
Full frame rate ISMA MP4 (at 550 or 300 MB/hr)

The difference in time to compress between the speed optimised and normal presets can be a factor of five or more, but with a corresponding difference in the resulting file size and quality.

Note that you should not access the preview files from the preview directory directly. They are private to CatDV - this is why they have obscure names like "25,123,4210,64x.mov". Instead, use the Export As Movie(s) command, where you can choose to export existing previews as either reference or self contained movies without recompressing them.


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