How to Convert AVI to MP4 Without Losing Quality (and Why It’s Worth Doing)

I found a box of old DVDs at my parents’ place last year. Most of them had been burned from a camcorder around 2008, and when I finally ripped them, every single file came out as an AVI. My laptop played them. My phone didn’t. The TV in the living room just put up a little grey “unsupported” message, which felt a bit rude given the circumstances.

If that sounds familiar, the fix is easier than it looks. Convertio is a website that converts files from one format to another right in your browser, no software to install, and its avi to mp4 page is the one I ended up using for that whole box. You drop the file in, pick a couple of settings, and download an MP4 that plays on basically anything. That said, there are a few settings worth understanding first, because they’re the difference between “looks the same” and “why is it suddenly blurry?”

Converting an AVI file into a widely supported MP4

Alt text: Illustration of an AVI file being converted into an MP4 file  |  File: a1-featured.webp

Table of Contents

•       So what’s the actual difference?

•       Why your AVI files keep getting rejected

•       AVI vs MP4, side by side

•       Converting with Convertio, step by step

•       The settings I’d actually change

•       Mistakes I made so you don’t have to

•       Last thoughts

So What’s the Actual Difference?

Here’s the bit that confused me for years. AVI and MP4 aren’t really video formats in the way people think. They’re containers. Boxes, basically. Inside sits the video, the audio, sometimes subtitles, and the codec is the thing that decides how all that picture data gets squashed down.

AVI is old. Microsoft brought it out in 1992 with Video for Windows, back when a 2 GB file was considered huge. The Library of Congress has a format page on it that mentions that 2 GB ceiling, which later got patched with something called OpenDML. MP4 turned up in 2003. These days it usually carries H.264 or H.265 video with AAC audio, and it’s happy holding chapters, extra audio tracks and subtitles too.

What sits inside a video container

Alt text: Diagram comparing what an AVI container and an MP4 container hold  |  File: a1-container.webp

Why Your AVI Files Keep Getting Rejected

Nothing’s actually wrong with AVI. The rest of the world just stopped caring about it. In my case it came down to a few things:

•       The video inside was Xvid, which my phone had no idea what to do with. DivX and uncompressed AVIs cause the same headache on a lot of TVs.

•       You can’t drop an AVI into a web page and expect a browser to play it. Upload forms on course sites and social apps often refuse them outright.

•       Some of those camcorder files were enormous. One 20-minute clip was bigger than a whole folder of holiday photos, so emailing it was never going to happen.

•       Subtitles were a pain too, because AVI doesn’t really do modern subtitle formats.

MP4 with H.264, on the other hand, is about as close to “it just works” as video gets right now.

AVI vs MP4, Side by Side

Converting With Convertio, Step by Step

You don’t need an account for a normal conversion, which I appreciated.

1.     Go to the AVI to MP4 page and drag your file onto it. If it’s sitting in Google Drive or Dropbox, you can pull it in from there instead.

2.     MP4 should already be chosen as the output. Got a pile of clips? Add them all at once and they’ll go through together.

3.     If you want to tweak anything, click the little gear icon. I’ll get to which settings matter in a second.

4.     Press Convert, wait a minute or two, then download it (or send it straight back to your cloud storage).

Free uploads can be up to 1 GB each. And because these were family videos, I did check the privacy side. Convertio’s security page says your uploaded file gets deleted as soon as it’s converted, and the finished one is wiped after 24 hours. So grab your download fairly quickly.

The Settings I’d Actually Change

Honestly, most people can leave everything alone. But if you open the gear menu, this is what I’d look at.

Codec. Go with H.264. H.265 makes smaller files, sure, but older phones and TVs sometimes won’t play it, and that defeats the whole point.

Resolution. Leave it where it is. My camcorder footage was 720×576. Bumping it to 1080p wouldn’t have added a single bit of real detail. It would just have made a bigger, equally soft file.

Quality. Don’t go for the lowest setting to save space. If the AVI was already compressed, squeezing it hard a second time is where the blockiness creeps in. Somewhere in the middle to high end is fine.

The “copy” option. This one’s handy. If the video inside your AVI is already H.264 (some newer AVIs are), choosing copy just moves it into an MP4 box without re-encoding anything. No quality change at all.

Mistakes I Made So You Don’t Have To

Learn from my clumsiness, basically:

•       I deleted two of the originals the same evening, before watching the MP4s through. One of them had the audio drifting slightly out of sync by the end. Lesson learned. Keep the AVI until you’ve checked the whole thing.

•       I converted a file that had already been converted once before, years ago, and it showed. If you’ve got the original anywhere, start from that.

•       For a while I thought bigger MP4 equals better MP4. It doesn’t. A sensible bitrate matters a lot more than the file size.

•       I almost stretched some old 4:3 footage to widescreen. Everyone looked like they’d been put through a pasta maker. Keep the aspect ratio as it was.

Last Thoughts

AVI had a good run, but it comes from a different era of computers. Moving those files to MP4 means they’ll play on today’s phones and TVs, they’re easier to share, and they usually take up a lot less space. Pick H.264, leave the resolution alone, check the result before you bin anything, and your old videos should be fine for a long while yet. Mine are now in a shared folder the whole family can actually open, which is more than the DVDs ever managed.