In article <bcc7d82b.0308271413.7928d379posting.google.com >,
[email]nradischoptonline.net[/email] (nr) wrote:
> I can find no doentation on how these macros works and how to use them.
> Could someone please point me to some docs please?
The Electric Image importer component has lots of good
comments/doentation on how these macros work.

See
<[url]http://developer.apple.com/samplecode/Sample_Code/QuickTime/Importers_an[/url]
d_Exporters/ElectricImageComponent.htm>
and specifically the file EI_CodecDispatch.h seems to have what you are
looking for.