Module.instantiateWasm callback failed with error: out of memory

**Describe the bug**
Getting out of memory issue with small files (893 Kb).

**To Reproduce**

`data` below is a video-only `Blob` from a webcam.

```javascript
async convert(data) {
const { createFFmpeg, fetchFile } = FFmpeg;
const ffmpeg = createFFmpeg({
corePath: this.convertWorkerURL,
log: this.debug
});
const name = "foo";

// load and convert blob
await ffmpeg.load();
ffmpeg.FS('writeFile', name, await fetchFile(data));
await ffmpeg.run('-i', name, 'output.mp4');
const output = ffmpeg.FS('readFile', 'output.mp4');

// create new blob
let result = new Blob([output.buffer], { type: 'video/mp4' })
}
```

**Screenshots**

Process and error in screenshot below:


**Desktop (please complete the following information):**
- OS: Ubuntu 20
- Browser: Firefox
- Version 82