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Osprey 240e/450e User Guide
ViewCast 65
Default Output Size
Figure 60. Default Output Size
The standard DirectShow Pin Properties dialog allows you to select the height and width of captured
video (Figure 60) from a drop-down list. The drop-down list has a particular range of choices that may or
may not fit your needs. The drop-down list includes one default size that may or may not fit your needs.
The drop-down list includes one default size that is provided by the capture driver. The Default size
control allows you to set up what default size will be shown.
If you click Auto Size, your default video size is sized automatically to your crop settings. The three radio
buttons, 1X, 1/2X, and 1/4X, determine whether the output size is scaled down from the crop size.
Example 1: If you are running standard 640 x 480 NTSC video, and you do not enable Enable Cropping,
your crop size is 640 x 480. With Auto Size enabled, and 1X selected, your default size is 640 x 480; with
1/2X, 320 x 240; and with 1/4X, 160 x 120.
Example 2: If you have enabled cropping with size 320 x 240 (one quarter of the full video area), the
default Auto Sizes are as follows: 1X, 320 x 240; 1/2X, 160 x 120; 1/4X, 80 x 60.
If you leave Auto Size disabled, the default size radio buttons are disabled and the height and width edit
boxes are enabled. You can set any default size with the following two restrictions:
Since the driver does not upscale video, the default size must be smaller than the crop size.
For example, if the crop size is 320 x 240, you cannot set default output size 400 x 300.
Sizes are subject to the granularity requirements of the selected video format, as explained
in the Granularity section above. For example, if your video format is I420 and you try to set
a default width of 360, it gets adjusted down to 352 as soon as you click on another control.
Pin Properties dialog default entry does not appear in the default VFW/DirectShow mapper dialog. Thus,
unless a VFW application, like Virtual Dub, specifically allows for custom resolutions, the VFW app is only
able to select from the options the VFW/DirectShow mapper lists.