Check fps of source and set for output

[joley-gh]

These changes add the mediainfo tool to analyze the source media and get the frame rate.
The mediainfo binary was installed with brew on my M2 and seems to be a Mach-O 64-bit executable arm64.
It might be better to replace it with a x64 version to support all systems.

With the extracted framerate it is possible to force mkvmerge to use the correct framerate.

[nekno]

Hi @joley-gh, thanks for your PR! Would you say this is a common problem you're encountering, or how often would you say an incorrect framerate is an issue?

I've never run into it as a problem, so I'm hesitant to rely on MediaInfo to force a framerate when the source typically should have it set as intended.

[joley-gh]

Hey @nekno
I encountered the problem when submitting a profile 8 file, which content mapping I wanted to convert from v4.0 to 2.9.

To invetigate further I tested some more files:

1. Profile 8, (CM v2.9), Frame Rate 23.976 FPS
   -> file size reduced (strange) + Frame Rate 25.000 FPS

2. Profile 8, (CM v4.0), Frame Rate 24.000 FPS
   -> file size reduced (ok since cm data gets removed) + Frame Rate 25.000 FPS

3. Profile 7, (CM v4.0), Frame Rate 23.976 FPS
   -> file size reduced (ok since cm data gets removed) + Frame Rate 23.976 FPS

When converting from profile 7 to 8 the fps problem does not arise.
Something seems to go wrong when a file with profile 8 is provided. The frame reate is always set to 25.000 in that case.

The file reduction in test 1 is weird and also occures with my fix. It also occures if I set the entries in config.json to false.

[nekno]

Hi @joley-gh — I've been attempting to find cases where this is needed, but I just haven't run across it. Do you think this is something that's routinely needed, or more likely an edge case you encountered in a file or two?

Adding the additional mediainfo binary plus all the processing to find and set the framerate when it isn't typically needed is a lot of overhead. There's also potential it could set the values incorrectly or make other undesirable changes.