Intro movie and demo don't play on Windows 11

[CookiePLMonster]

Tonight I upgraded to Windows 11 23H2, and I... lost the intro movies. The game starts immediately now, and pressing Demo flashes the black screen and immediately back to the main menu.

I guess it could be a cool quality of life feature to add a SkipIntro option, but the movie playback should not be permanently broken like this.

[CookiePLMonster]

Indeo Video 5 used for those vids is apparently no longer supported on Win11.
https://learn.microsoft.com/en-us/answers/questions/3885130/need-drivers-for-vids-iv50-decompressor

Re-encoding the movies via ffmpeg does not help. I suspect the game wants Indeo5 specifically and doesn't just encode anything.

[CookiePLMonster]

I had ir50_32.dll in my system already, just needed to re-register it as per this post:

cd C:\Windows\SysWOW64
regsvr32 ir50_32.dll

While this is a valid fix, I think for D2GI we may be able to do better: ir50_32.dll seems to still be shipped with Windows 11, as it's there even on a clean Windows Sandbox, and it's simply not registered. We may be able to modify the game to load that DLL directly, instead of relying on registrations. This will fix this "compatibility" issue without the need to ship any extra DLLs.

EDIT:
A clean Win11 24H2 machine doesn't ship that DLL, but it has ir32_32.dll. So maybe shipping the DLL will be necessary after all, but I think that'd be fine.

[CookiePLMonster]

The codec appears to be located through GetAVIInfo.dll that is loaded through CoCreateInstance itself. Both this DLL and the Indeo codec are registered in the system at installation time if you install the game from GOG:

IF %_os_bitness% == 32 (	
	%SYSTEMROOT%\system32\regsvr32.EXE /s %SYSTEMROOT%\system32\ir50_32.dll
	%SYSTEMROOT%\system32\regsvr32.EXE /s "%~dp0\GetAVIInfo.dll"
) ELSE (		
	%SYSTEMROOT%\SysWOW64\regsvr32.EXE /s %SYSTEMROOT%\SysWOW64\ir50_32.dll
	%SYSTEMROOT%\SysWOW64\regsvr32.EXE /s "%~dp0\GetAVIInfo.dll"
)

Making GetAVIInfo work without registration will be trivial, but ir50_32.dll may be a bit more involved. It may require hooking into GetAVIInfo.dll as it loads.

[AlexKimov]

https://github.com/DmitriiSukhomlinov/softlab-nsk/blob/master/avi/MFC/COM/GetAVIInfo/GetAVIInfo.doc

[CookiePLMonster]

This is handy! I'm not sure why they opted to go for registering this DLL in the first place, but I'm convinced I can get around it.