RangeError: WebAssembly.Memory(): could not allocate memor

**Describe the bug**
There are like 5 of these memory issues up top and you aren't doing anything about it.

**To Reproduce**
1. Try to use ffmpeg.
2. Notice ffmpeg takes 18 gigabytes to make a slideshow out of 30 images.
3. Notice `ffmpeg.exit` does nothing.
4. Notice manually deallocating memory with `ffmpeg = null` stlil does nothing.
5. Post bug report because you need to fix your shit.

**Expected behavior**
I don't expect 30 images totalling < 50MB to take 18GB of memory to create fadein/out transitions.

I don't expect ffmpeg to hold on to memory between jobs. So I don't expect to need an additional 18GB of memory because I want to use a turing complete language feature and you've successfully removed loops from the language because this lib is unusable in it's current state for... loops.

**Screenshots**
Really?

**Desktop (please complete the following information):**
- OS: [e.g. iOS]
- Browser [e.g. chrome, safari]
- Version [e.g. 22]

**Smartphone (please complete the following information):**
- Device: [e.g. iPhone6]
- OS: [e.g. iOS8.1]
- Browser [e.g. stock browser, safari]
- Version [e.g. 22]

**Additional context**
Add any other context about the problem here.