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QuickTime and Native PowerPC

Q We are calling the DecompressImage() function from QuickTime in native PowerPC code (QuickTime for PowerPC is installed). The graphics compressor is very slow on the PowerPC. It seems that the graphics decompressor may not be ported to the PowerPC and that emulated code is called from native code. Is this true, and if so, what is the solution to this ?

A It's possible that the QuickTime PowerPlug file, which is the CFM library that contains the native codecs, isn't installed in your extension folder. Use the following code to test for availability of this library: 
/*  IsQuickTimeCFMInstalled
IsQuickTimeInstalled is used to initialize the environment

pascal Boolean    IsQuickTimeCFMInstalled(void)

DESCRIPTION
    IsQuickTimeCFMInstalled will test if the CFM QuickTime libraries are
    present (QuickTime PowerPlug, for instance), and if the libraries
    are still present (this because the libraries are registered once
    when Gestalt finds then during runtime, and the end user might
    delete these, or move them to another location later)(.
*/

pascal Boolean IsQuickTimeCFMInstalled(void)
{
    OSErr     anErr;
    long         qtFeatures;

// Test if the library is registered.
    anErr = Gestalt(gestaltQuickTimeFeatures, &qtFeatures);

    if (!(  (anErr == noErr)  &&
    (qtFeatures & (1 << gestaltPPCQuickTimeLibPresent))
    )) // not true
          return false;

// Test if a function is available (the library is not moved from the
// Extension folder),
// this is the trick to be used concerning testing if a function
// is available via CFM.
    if   ( ! EnterMovies )
        return false;
    else
        return true;
}

You should also be using the QuickTimeLib or QuickTime.xcoff files, which are needed to link together the native code that uses the CFM PowerPlug libraries.

Since the component manager and core parts of QuickTime are not yet native, you will encounter context switches, sometimes frequently (these are usually 50 cycles in length). The gain from using native codecs decreases as the number of context switches increases. However, in the case of the CinePak codecs, we've observed a gain of four times or more during the compression stage.

[May 01 1995]

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