The ACM functions fall into several categories. Naming conventions for the functions make it easy to identify these categories. Function names (with two exceptions) are of the form acmGroupFunction, where Group designates the ACM category (such as "Driver," "Format," "FormatTag," "Filter," "FilterTag," or "Stream"), and Function describes the action performed by the function.
The functions in the filter and format groups are very similar. Almost every function that acts on filters has a parallel function that acts on formats.
In the format group, some functions use waveform-audio format tags (the wFormatTag member of a WAVEFORMATEX structure) while others require full waveform-audio formats (the full WAVEFORMATEX structure). (For reference information about the WAVEFORMATEX structure, see Error.)
In the filter group, some functions use waveform-audio filter tags (the dwFilterTag member of a WAVEFILTER structure), while others require full waveform-audio filters (the full WAVEFILTER structure).
The functions in the stream group represent the many steps involved in a conversion: opening a conversion instance, preparing for the conversion, performing the conversion, cleaning up after the conversion is complete, and closing the conversion instance.