AVI to MP4 Converter — Free & Private
Rescue old camcorder footage and Windows Movie Maker exports from the 2000s. Convert DivX, Xvid, and MJPEG-encoded AVI files to H.264 MP4 — playable on every iPhone, smart TV, and social platform. No upload, ever.
Why AVI Files Stop Playing on Modern Devices
AVI (Audio Video Interleave) was introduced by Microsoft in 1992 — making it older than the web itself. It became the default export format for MiniDV camcorders, Windows Movie Maker, and DVD-ripping tools throughout the 2000s. The problem isn't the container itself — it's the codecs trapped inside. DivX and Xvid were revolutionary for their era, compressing VHS-quality footage onto CD-Rs. But Apple blocked these codecs from iOS entirely, and modern smart TVs, streaming platforms, and social media all expect H.264. Converting to MP4 re-encodes your footage with today's standard codec — cutting file size by up to 90% and making videos playable on every device made in the last decade.
- 📱 iPhone & iPad compatible — H.264 MP4 plays natively on every Apple device without extra apps
- 📉 3–10× smaller files — H.264 is dramatically more efficient than DivX, Xvid, or MJPEG
- 📺 Smart TV ready — MP4/H.264 is the universal standard for Samsung, LG, and Sony TVs
- 🎞️ YouTube & Instagram ready — upload directly with no slow re-processing on the platform
- ▶️ Streaming supported — MP4 supports progressive download; AVI requires full download before playback
- 🔒 100% private — FFmpeg.wasm runs in your browser; no footage ever touches a server
How to Convert AVI to MP4
Click "Convert Now" to open the video converter with AVI → MP4 pre-selected.
Drag & drop your AVI or click Browse. Works with DivX, Xvid, MJPEG, and other AVI variants.
FFmpeg.wasm re-encodes your video to H.264 MP4 entirely in your browser — no server upload.
Your MP4 downloads automatically, ready for phones, TVs, YouTube, and social media.
AVI vs MP4 — Format Comparison
AVI (Audio Video Interleave) and MP4 (MP4 (MPEG-4 Part 14)) use different compression and storage methods. The table below shows the key technical differences. AVI from 1992. Files are often 3–5× larger than equivalent MP4. MP4/H.264 is the dominant video format for web and device playback.
Features
100% Private
FFmpeg.wasm runs locally. Your footage never leaves your device.
Multi-Codec AVI
Handles DivX, Xvid, MJPEG, and uncompressed AVI from any era.
Free Forever
No account, no fee, no watermarks. Convert as many files as you need.
Massive Size Reduction
H.264 encoding cuts file size by 60–90% versus old AVI codecs.
Universal Output
MP4/H.264 plays on every device, OS, and platform without extra software.
Audio Preserved
Audio re-encodes to AAC — the standard audio format for MP4 files.
Key Questions About AVI to MP4, Answered
Direct answers structured for AI extraction, voice search, and featured snippets.
Will my video be re-encoded or just remuxed when converting AVI to MP4?
Almost always re-encoded. AVI files from the 2000s typically carry DivX or Xvid video, and MP4 doesn't support either codec — so the video has to be transcoded to H.264 before it can go in an MP4 container. The one exception is an AVI that already holds H.264 (some newer capture software wraps H.264 in AVI); in that case the conversion is a fast remux with no quality change at all.
- DivX/Xvid AVI (the vast majority of old AVI files): always re-encoded to H.264 for MP4
- H.264-in-AVI (rare, modern capture tools): remuxed instantly with zero quality loss
- Convertlo re-encodes at CRF 18 — visually indistinguishable from the source at normal viewing distances
Will the output MP4 play on iPhones, Android, and smart TVs?
Yes — once your AVI is converted to MP4 with H.264, it becomes the most universally playable video file there is. Every iPhone since the iPhone 3G, every Android phone, every smart TV released in the last decade, and every major social platform opens MP4/H.264 without a second thought.
- iPhone & iPad: native playback, no app needed
- Android: native support across every manufacturer
- YouTube, Instagram, TikTok: all accept MP4 directly — no further conversion needed
- Smart TVs and streaming boxes: MP4/H.264 is the baseline format every device supports
How much will the file size change going from AVI to MP4?
Expect a big drop. Old AVI files encoded with DivX or Xvid are notoriously inefficient by today's standards — a 700 MB AVI of a TV episode often shrinks to under 150 MB as an H.264 MP4 at the same resolution, simply because H.264 compresses video far better per bit of quality.
- DivX/Xvid AVI → H.264 MP4: typically 3–10x smaller at visually equivalent quality
- The size reduction comes from the codec, not the container — MP4 itself adds negligible overhead
- If your AVI already contains H.264, expect the MP4 to be roughly the same size (remux, no re-encode)
What bitrate should I use when batch-converting a large AVI collection to MP4?
For SD/480p AVI files, 1–1.5 Mbps H.264 is enough. For 720p, use 2.5–4 Mbps. For 1080p, 4–6 Mbps. These ranges match streaming-platform output bitrates and keep converted files at a manageable size.
- 480p (SD): 1–1.5 Mbps H.264 — matches DVD-quality streaming; files stay under 1 GB per hour
- 720p: 2.5–4 Mbps — comparable to 720p YouTube streams; good balance of size and quality
- 1080p: 4–6 Mbps — matches Netflix HD; use VBR to handle action scenes better than CBR
Go Deeper: AVI to MP4 Resources
In-depth articles to help you understand the formats, pick the right settings, and get the best results.