Source code of Windows XP (NT5)
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======================================================== | | | CONVERSION AND PORTABILITY ITEMS IN NT MULTI-MEDIA | | | ========================================================
1. SHORT MIDI MESSAGES (RCBS)
Short midi messages are passed around the system as DWORDs. The documentations says that the first byte is the 'low order byte' (see midiOutShortMsg). However, testcases (eg sbtest.exe) and presumably applications often just use a union of a dword and byte[4] to convert (NOT the same).
2. WINDOW words
The apis now take LONG parameters but actually only store WORDs. This can be fixed by using things like SetWindowLong but there is still the problem of the offsets they are using. One suggestion is just to double the size of everthing and every offset but the conversion effort is still there.
3. (SD) MCI Device IDs
Unfortunately these are 16 bits values in Win 3.0+, and the size is difficult to change as it is used in disk files. Hence is a permanent fixed value. It could be "thunked" when read/written. More work needs to be done to decide whether to use a 32 bit device id for MCI devices in Win 32, or to stick with 16 bit. The device type MCIDEVICEID has been added to WINMM.H.
4. (SD) Global sound playing windows
Windows MM extensions (MMSYSTEM) uses a single GLOBAL window handle (hwndNotify) to play all asynchronous sound (MCI and sndPlaySound). To do this a piece of global memory is used that defines which sound is playing. NO attempt is made in Windows (WIN16) to synchronise playing sounds.
Much of the WIN16 high level sound code references the global window handle.
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