Technical Q&A QA1226

Video Output Components - QTVideoOutputGetIndImageDecompressor

Q: QTVideoOutputGetIndImageDecompressor doesn't seem to be documented; what is this call used for?

A: QTVideoOutputGetIndImageDecompressor is implemented by the Base Video Output Component and is used internally by QuickTime to retrieve the decompressor codec component associated with a specific Video Output Display Mode.

Video Output Component developers:

Developers of Video Output Components should simply delegate this call to the Base Video Output Component in their dispatcher.

ComponentDelegate (GetIndImageDecompressor)

Application developers using Video Output Components:

Application developers should not call this API directly. They should however call SetMovieVideoOutput to notify the Image Compression Manager that a Video Output Component is being used with a given Movie.

What is the Video Output Display Mode List?

A Video Output Components Display Mode List is stored in a QT Atom Container and contains each display mode supported by the Video Output device. When an application displays video on a Video Output device, it must select which of the device's display modes to use. The mode determines how video is displayed and contains a list of characteristics for that mode. These characteristics include Height, Width, Resolution, Refresh Rate etc. A display mode can also include a list of decompressor components provided specifically for the video output device and required for the mode. The Display Mode List is returned by calling QTVideoOutputGetDisplayModeList.

References:

SoftVideoOutputComponent sample code

SetMovieVideoOutput

QTVideoOutputGetDisplayModeList

QuickTime Video Output Components

[Jan 03 2003]