Anim8or Community

Try VirtualDub, https://www.virtualdub.org/

Edit:  Oops, VirtualDub doesn't recognize MP4 files.  Hmm, well you might be able to find something else on the web that'll suit your needs.  I typed "convert MP4 to frames" into Google and found several possibilities...

Glad to hear things are more or less sorted.  I have no doubt you will once again hone your skills with Anim8or, much like riding the proverbial bike. 

I particularly like the "mouth" on top of the bishops 

Ummmmm, I believe that's a mitre, the type of head covering bishops wear (see https://en.wikipedia.org/wiki/Mitre):

I think you probably already know the answer to that, since that's what you're experiencing.  As has been mentioned to you before, the more polygons there are in a model or in a scene, the more computations the renderer must make.  More objects means more polygons, so longer render times. 

There are certain "tricks" that you may be able to use to help reduce render times for these scenes, like "freezing" a background, but that depends on how much movement your camera and/or subject makes within a scene.   

mrbeaver.07 ---
One thing that can make renders take a long time is lots of ploygons, because the renderer has to account for each and every one.  Some of your characters look like you've applied a lot of subdivisions.  Unfortunately, while subdividing can really help to smooth objects, it also adds a LOT of polygons.  While a little subdividing may be warranted, subdividing more than once REALLY bumps up render times!

The best way to reduce the amount of subdividing is to model shapes properly in the first place.  This is not always so easy, but you'll reap rewards in lower render times.

Ah, a head-smack moment.  Not to worry, I've had PLENTY of those myself!

If it's not copyrighted material, it's definitely not a cheat.  Besides, there are PLENTY of free videos and models available that one could "reverse-engineer" in order to gain valuable insight to methodology and techniques.

Old Codger ---
I agree with davdud101 and johnar, that while materials and texturing are important, much of the "realism" you see in renders is due to attention to lighting.  And in that regard, it's important to use "real" lighting.  That is, there is no such thing as "ambient" lighting in a photo shoot.  The type of light source, and the falloff of lighting --- that is, its intensity diminishes with distance --- are important.

I "used to have" several Anim8or projects (on a computer that crapped out) for which I also had some rather good renders, and I remember "in the old days" that a couple of Anim8ors had some excellent models and renders of automobiles, but here are a few hobby projects I did using LightWave some years ago.  Granted, each may not be in a realistic setting, but my intent at the time was to get a certain "look."