Video Output Components

Video output components allow you to send QuickTime video to devices that are not recognized as displays. These components are used directly by QuickTime applications to allow the user to send movie output to these external devices. For example, Digital Video (DV) and Firewire capable cameras.

QuickTime applications can use a video output components by selecting the component, configuring it, and associating it with a GWorld.

A video output component receives QuickTime video data and delivers the data to a video output device for display. If the incoming data is in a format that the video output device can display directly, the video output component can simply send the data to the video output device. If the incoming data cannot be displayed directly, the video output component must use a transfer codec or decompressor component to convert the data to a format that the video output device can display.

A video output device has one or more display modes. The characteristics of each mode determine how video is displayed. When any software displays video on a video output device, it must select which of the device's display modes to use.

The characteristics of a display mode include.

• The height of the displayed image, in pixels.
• The width of the displayed image, in pixels.
• The horizontal resolution of the display, in pixels per inch.
• The vertical resolution of the display, in pixels per inch.
• The refresh rate of the display, in Hertz.
• The pixel type of the display.
• A text description of the display mode.

The characteristics can also include a list of decompressor components required for the mode and provided specifically for the video output device. If a video output device cannot directly display any of the pixel formats supported by QuickTime, the vendor of the device must provide one or more special decompressors (transfer codec) to convert supported pixel formats to a format the device can display. If a video output device can display one or more of the pixel formats supported by QuickTime, the Image Compression Manager can use standard decompressors that are included with QuickTime, and the list of special decompressor components can be empty.

References

Video Output Components