Convert from .ts to .mp4 while cropping black bars & little quality loss?

[nobodyhome]

I downloaded video from a streaming site (legit and free, not a subscription based site like Netflix, Amazon, or Crunchyroll either) and I need to crop the black bars on either side of the video and convert it from .ts to .mp4 with as little quality loss as possible. I realize that cropping the bars means encoding it which means some quality loss, but I'm unsure of the settings to ensure as little as possible.

I tried both Avidemux and HandBrake with default settings and the resulting file goes from 500+ MB to 150-some MB when just cropping the bars. It's 4:3 originally, but the site added black bars to make it 16:9.

Here's a link to the .ts file.

I don't know how to use Avisynth and don't think I'd be able to handle it yet based on what I've read while trying to learn.
If possible I'd like to stick to Avidemux or HandBrake.

Advice?

[poisondeathray]

Why do you need to crop it ?

You can set the CRF to a lower value in avidemux, or handbrake (I think it's called quality factor there). It's inversely proportional (lower values result in larger filesizes, higher quality)

[nobodyhome]

As I mentioned I need to crop it since the video is originally 4:3 (fullscreen), but the site added black bars to make it 16:9 (widescreen). I know screens are almost always widescreen these days so it probably doesn't matter that they're there, but for my purposes that black bars are in the way.

What's a good value for the CRF? Will too low a number make the resulting file size larger than the original or have unnecessary effects?

[poisondeathray]

As I mentioned I need to crop it since the video is originally 4:3 (fullscreen), but the site added black bars to make it 16:9 (widescreen). I know screens are almost always widescreen these days so it probably doesn't matter that they're there, but for my purposes that black bars are in the way.

So if you crop it, the active content will still be 4:3 . That doesn't change. When you view it on a 16:9 widescreen display, the bars will come back when you view it properly (they will be put on by the player to preserve the AR). There is no benefit to cropping (lose quality, waste time re-encoding)

What's a good value for the CRF? Will too low a number make the resulting file size larger than the original or have unnecessary effects?

Typically for general use 16-22 . If 22 gave too small, try 16. Yes, too low will give sizes larger than the original