Stuck at stream mapping

**Describe the bug**
When trying to convert a `.mp4` to `.gif` it gets stuck at stream mapping.

I am using version `0.12.6`

Tried with:
```

const file: File = new File([blob], 'videoToBeConverted', { type: blob.type });

const nameIn = file.name;
const nameOut = 'output.gif';

const arrayBuffer = await file.arrayBuffer();

await ffmpeg.exec([
'-i',
nameIn,
'-vf',
'fps=10,split[s0][s1];[s0]palettegen[p];[s1][p]paletteuse',
nameOut,
]);
```

and

```
const file: File = new File([blob], 'videoToBeConverted', { type: blob.type });

const nameIn = file.name;
const nameOut = 'output.gif';

const arrayBuffer = await file.arrayBuffer();

await ffmpeg.exec([
'-i',
nameIn,
'-t',
'2.5',
'-ss',
'2.0',
'-f',
'gif',
nameOut,
]);
```

Even tried just converting the `.mp4` to `.mov` and still got stuck.

**To Reproduce**
Cannot provide a reproducible project.

**Expected behavior**
Conversion should start and be logged.

**Screenshots**

**Desktop (please complete the following information):**
- OS: MacOS
- Browser Chrome
- Version 116

**Additional context**
N/A