You downloaded an old video, or dug one out of an archive, and your Mac just stares at it. Double-click an AVI and often nothing happens. QuickTime doesn’t speak AVI, and the DivX or Xvid codecs inside many AVI files are from a different era of the internet.

Convert it to MP4 and the problem disappears. MP4 with H.264 plays on every Mac, phone, browser, and editor. Here are four ways to do it.

Quick answer: To convert AVI to MP4 on a Mac, re-encode it with a free tool like HandBrake for one file, or a batch converter like Picmal for a folder of them. Both re-encode the old AVI to a modern H.264 MP4 that plays natively on your Mac, no upload required.

Why AVI is a headache on a Mac

AVI is a Microsoft container from 1992. It still shows up in downloads, old camcorder footage, and archives, but the Mac ecosystem moved on:

  • QuickTime can’t open most AVI files and Preview won’t touch them
  • The DivX/Xvid codecs inside are rarely supported by modern Apple software
  • Editors reject it, so you can’t drop an AVI into iMovie or Final Cut

MP4 solves all three. It’s the format everything expects now.

Method 1: Picmal (fastest for batches)

Picmal is a native Mac app for converting video. If you have more than one AVI, this is the quickest route.

Steps:

  1. Download Picmal from picmal.app
  2. Drag in your AVI files, or a whole folder
  3. Choose MP4 as the output
  4. Set a quality level if you want to control size
  5. Click Convert

Why people reach for it:

  • Converts a folder of AVIs in one pass instead of one at a time
  • Runs entirely on your Mac, nothing uploaded
  • Uses hardware encoding, so it’s fast on Apple Silicon
  • No file size limit and no watermark

Best for:

Cleaning up an archive of old AVI clips into something modern and playable.

Method 2: HandBrake (free standard)

HandBrake is the free, open-source workhorse and opens AVI without trouble.

Steps:

  1. Download and open HandBrake
  2. Drag in your AVI file
  3. Set the format to MP4
  4. Pick a preset like Fast 1080p30 (H.264)
  5. Click Start

Worth knowing:

Busy interface, sensible defaults. It has a queue for multiple files, but you add them one at a time.

Method 3: VLC (plays and converts AVI)

VLC opens AVI when nothing else will, and it converts too.

Steps:

  1. Open VLC → File → Convert / Stream
  2. Drop in your AVI file
  3. Choose the Video - H.264 + MP3 (MP4) profile
  4. Click Save as File, pick a destination
  5. Save to start

The catch:

Basic converter, one file at a time, minimal progress feedback. Fine for the occasional file.

Method 4: FFmpeg (command line)

For scripting or bulk jobs:

brew install ffmpeg

A single file:

ffmpeg -i input.avi -c:v libx264 -crf 20 -c:a aac output.mp4

Every AVI in a folder:

for f in *.avi; do
  ffmpeg -i "$f" -c:v libx264 -crf 20 -c:a aac "${f%.*}.mp4"
done

Free, and easy to loop over a folder of old clips at once. Worth it only if you’re comfortable in the terminal.

Side-by-side comparison

MethodSpeedBatchEase of usePrice
PicmalVery FastExcellentVery Easy$15.99
HandBrakeModerateGoodModerateFree
VLCSlowNoneEasyFree
FFmpegFastExcellentTechnicalFree

Tips

  • Keep a high quality setting (CRF around 20). Old AVI footage is precious; don’t crush it.
  • Check the audio track survived. AAC is the safe, universal choice.
  • MP4 is often smaller than the AVI original at the same quality, thanks to modern H.264 efficiency.

The short version

  • One file, free: HandBrake, or VLC if HandBrake can’t open it
  • A whole folder, fast and local: Picmal
  • Scripting it: FFmpeg