SGGetVideoCompressor(IM: QC)

Inside Macintosh: QuickTime Components /

Chapter 6 - Sequence Grabber Channel Components / Sequence Grabber Channel Components Reference

Functions / Configuration Functions for Video Channel Components

SGGetVideoCompressor
The SGGetVideoCompressor function allows the sequence grabber component to determine your channel's current image-compression parameters.
pascal ComponentResult SGGetVideoCompressor (SGChannel c,
                                 short *depth, 
                                 CompressorComponent *compressor, 
                                 CodecQ *spatialQuality, 
                                 CodecQ *temporalQuality, 
                                 long *keyFrameRate);
c
Identifies the channel connection for this operation.
depth
Contains a pointer to a field that is to receive the depth at which the image is likely to be viewed. Image compressor components may use the depth as an indication of the color or grayscale resolution of the compressed images. Return the depth value currently in use by your channel component. If this parameter is set to nil, the sequence grabber component is not interested in this information.
compressor
Contains a pointer to a field that is to receive an image compressor identifier. Return the identifier that corresponds to the image compressor your channel is using. If this parameter is set to nil, the sequence grabber component is not interested in this information.
spatialQuality
Contains a pointer to a field that is to receive the desired compressed image quality. Return the current quality value. See the chapter "Image Compression Manager" in Inside Macintosh: QuickTime for valid values. If this parameter is set to nil, the sequence grabber component is not interested in this information.
temporalQuality
Contains a pointer to a field that is to receive the desired temporal quality of the sequence. This parameter governs the level of compression you desire with respect to information between successive frames in the sequence. Return the current temporal quality value. If this parameter is set to nil, the sequence grabber component is not interested in this information.
keyFrameRate
Contains a pointer to a field that is to receive the maximum number of frames allowed between key frames. Key frames provide points from which a temporally compressed sequence may be decompressed. This value controls the frequency at which the image compressor places key frames into the compressed sequence. Return the current key frame rate. If this parameter is set to nil, the sequence grabber component is not interested in this information.

SEE ALSO
The sequence grabber component can set these parameters by calling the SGSetVideoCompressor function, which is described in the previous section.