Modernising old AVI videos: converting them to MP4 to play everywhere and save space

AVI is a container created by Microsoft in 1992. It was designed long before modern codecs, and it carries them poorly. AVI files from the 2000s most often contain video in MPEG-4 Part 2, popularised under the names DivX and Xvid, and sound in MP3.

That video codec is no longer natively supported by many recent devices: iPhones and iPads do not play it with their built-in apps, many TVs have dropped it, and sharing platforms often reject it. The file is not damaged: it is the players that no longer speak its language.

Lacking an old tape to hand, we recreated a typical AVI from that era from our test video: 30 seconds at 640 × 360 pixels and 30 frames per second, good-quality Xvid video and 128 kbps MP3 sound, 25 MB in total. We then converted it to MP4 with FileXvert's settings, first with no reduction, then with balanced reduction. Fidelity is measured against the AVI itself.

The result is clear: at a very similar visual quality, the MP4 weighs almost three times less than the AVI. H.264, released in 2003, compresses far more efficiently than Xvid, and that gap works entirely in your favour. Across a collection of several tens of gigabytes, the space saved becomes considerable.

Balanced reduction goes further, but on a video that is already small and already compressed, the loss becomes visible (0.940). For memories, no reduction is the right choice: it modernises the file without adding noticeable degradation.

Let us be clear: converting an old video does not make it look better. A 640 × 360 video will stay 640 × 360, with its original blur, noise and compression artefacts. FileXvert does no upscaling or AI restoration; it changes the format so that the video plays everywhere, without increasing its resolution.

Another point to watch: each re-encode adds a small loss. That is not a problem for a single conversion to a durable format such as MP4, but avoid converting the result again afterwards. Always start from the original AVI if you need to produce another version.

Finally, videos from DV camcorders or digitised tapes are often interlaced: each frame is made of two half-frames captured at slightly different moments, which shows up as comb-like lines on moving objects when watched on a modern screen. FileXvert keeps the video as it is, without deinterlacing it. If you see those lines, installed software such as HandBrake offers a deinterlacing filter to apply before or during conversion.

To modernise a collection of old videos without losing anything:

Conversion takes place in your browser, without sending your family videos to a server. The free plan accepts files up to 100 MB, which covers most clips from that era; beyond that, the Premium plan goes up to 2 GB.