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thank you, merged

https://github.com/ZDoom/gzdoom/pull/2506

I am moving this to bugs, this is a very important one.

        if (fpsdenominator > 1000 || fpsnumerator == 0 || fpsdenominator == 0)
        {
            // default to 30 fps if the header does not provide useful info.
            fpsdenominator = 30;
            fpsnumerator = 1;
        }

It seems to be a bug in GZDoom. According to a trace I made, the file has these properties: [c]fpsnumerator=1001[/c]/[c]fpsdenominator=20000[/c] (which equates to 0.05005 seconds per frame, or 19.98 fps). GZDoom in turn has this check in [c]VpxPlayer::ReadIVFHeader[/c]:
[code] if (fpsdenominator > 1000 || fpsnumerator == 0 || fpsdenominator == 0)
{
// default to 30 fps if the header does not provide useful info.
fpsdenominator = 30;
fpsnumerator = 1;
}[/code]
Because it has such a large denominator, GZDoom thinks the value is bad and assumes 30 fps, which makes it play ~1.5x too fast.

I'm not sure if this is a GZDoom bug or just a screwup on my end, but I'm posting this here in case it's the latter.

I'm currently trying to port over the cutscenes from the PS1 and Saturn ports of Hexen, but right out the gate I'm having issues with getting the intro cutscene to appear correctly. Original video here to give you an idea of how it's supposed to look: [url]https://www.youtube.com/watch?v=HaXyiYMXmis&pp=ygUPaGV4ZW4gcHMxIGludHJv[/url]

I'm far from familiar with how FFMpeg's command line arguments work, so I'm using Jakie's tutorial (https://forum.zdoom.org/viewtopic.php?t=76355) as a sort of guide. I can get the cutscene (extracted from the PS1 port via jpsxdec) to convert just fine, and it plays back properly in ffplay.exe, but when the IVF is actually used in GZDoom, it's played at about 1.5x the speed.

Here are the files to demonstrate this, in case someone with more experience in cutscene playback than I am can help me: https://drive.google.com/file/d/1Pc-5tuLxGN60aguyXNzqtZ9dkS1122Qk/view?usp=sharing

If this is actually a bug, the version of GZDoom I'm using is g4.12pre-485-gf0b96bff0.