The rendering progress bar is only quarterwise visible, and in the rendered video, also, only a portion of the actual clip is clean, the rest are a series of vertical or horizontal stripes. There was a similar issue on the replaymod website, but that user did not have any issue with the final product, and their issues disappeared on using a PC.

I am running replay mod 1.14.4 on Fabric through MultiMC on a Windows machine, if that helps.

I am sorry I can't describe this better, but I have attached a clip of the video and my log for that session:
2019_08_28_19_07_00_Moment
latest.log

update: the issue only seems to exist for render resolutions higher than my monitor resolution, a 720p video rendered just fine.

Any difference without all the other mods?
Either way, please post a log without them so it's clearer what's noise and what isn't.

Any difference without all the other mods?

That's strange, it doesn't seem to happen without the other mods.

i really don't have the time to see which mod specifically is causing this error, but i can only see optifine (or the porting mod) as the other mod affecting rendering or graphics in my list.

Here's a trimmed log from the same session with only replaymod, fabric, and optifine entries.
2019-08-28-3_modified.log