AVI vs MP4: Which Is Better?
For almost every use today, MP4. Both are containers, but AVI dates from 1992 and usually holds older codecs, while MP4 holds H.264 or HEVC and plays on every phone, TV and browser.
- Where AVI still makes sense: uncompressed or lossless capture (some editing and lab tools write AVI) and old DVD players with a DivX logo.
- Where MP4 wins: smaller files at the same quality, browser and phone playback, streaming with faststart, embedded subtitles and metadata.
- Quality: the container does not decide it; the codec and bitrate do. Converting cannot make an AVI look better, only more compatible.
What Is AVI?
AVI stands for Audio Video Interleave. Microsoft introduced it in November 1992 as part of Video for Windows, their answer to Apple's QuickTime technology. The format was designed to interleave audio and video data in alternating chunks, allowing simultaneous playback on the limited hardware of the early 1990s.
For over 15 years, AVI was the default video format on Windows PCs. The DivX and Xvid era (approximately 2000-2010) cemented AVI's dominance: nearly every video downloaded from the internet, ripped from a DVD, or captured from a camcorder was an AVI file. The classic "700 MB CD rip" was almost always a DivX-encoded AVI. For WMV, FLV and other formats from the same era, see our guide to old video file formats.
AVI files typically contain video encoded with Xvid or DivX (both implementations of MPEG-4 Part 2), paired with MP3 or PCM audio. Some older AVI files use even more primitive codecs like MS-MPEG4, Indeo, or Cinepak — codecs that modern decoders increasingly struggle to handle.
Key point: AVI is a container, not a codec. The AVI file itself is just a wrapper. The video quality depends entirely on the codec inside (Xvid, DivX, uncompressed, etc.) and the encoding settings used.
Why AVI Is Outdated
AVI was designed for 1992 hardware and software. By modern standards, it has critical limitations:
- Awkward B-frame handling: AVI has no proper timestamps, so B-frames (which reference future frames) need workarounds such as DivX’s “packed bitstream”. The codecs usually found in AVI (Xvid, DivX) are also older and less efficient than H.264, so files are larger at the same quality.
- Not built for the web: AVI keeps its index at the end of the file and no web browser plays it, so it is not used for streaming or embedding. MP4 can put its index (the
moovatom) at the start with faststart. - No standard subtitle track: AVI has no standard way to embed subtitles (DivX added its own XSUB format), so subtitles usually travel as separate .srt or .sub files. MP4 and MKV embed them directly.
- No chapter markers: No support for scene navigation or chapter markers that modern containers provide.
- Limited metadata: AVI's metadata support is minimal compared to MP4's rich tagging system.
- Fading codec support: AVI files made with old codecs such as Indeo, Cinepak or MS-MPEG4 often no longer play in current players without extra software.
| Feature | AVI (1992) | MP4 (2001) |
|---|---|---|
| B-frame support | Only with workarounds | Yes |
| Streaming | Not used on the web | Full (faststart) |
| Compression efficiency | Low (Xvid/DivX) | High (H.264/H.265) |
| Browser playback | None | All modern browsers |
| Mobile playback | Requires VLC | Native on iOS/Android |
| Subtitles | Mostly external files | Embedded |
Why AVI Files Still Exist
Despite being obsolete, AVI files remain common for several reasons:
- Legacy surveillance systems: Many security camera systems from the 2000s and 2010s output AVI files. Budget IP cameras and DVRs still use AVI as their default recording format.
- Old DVD rips: The massive library of DivX/Xvid DVD rips from 2000-2010 is still circulating. These 700 MB AVI files were designed to fit on a single CD-R.
- Camcorder recordings: Consumer camcorders from the DV era (MiniDV, Digital8) captured to AVI via FireWire. Many families have irreplaceable home videos in AVI format.
- Scientific and industrial equipment: Some laboratory instruments, microscopes, and industrial cameras still output AVI because their firmware was written decades ago.
- Screen recording tools: Older screen capture software (early Fraps, CamStudio) defaulted to uncompressed or Xvid AVI.
Benefits of Converting AVI to MP4
Converting AVI to MP4 (H.264) provides immediate, tangible improvements:
Massive file size reduction
H.264 is dramatically more efficient than the codecs found in AVI files. H.264 needs fewer bits than Xvid or DivX for the same picture, so the MP4 often comes out smaller. How much depends on the source: CRF lets the encoder choose the bitrate, and low-bitrate CD-era rips may shrink only a little. For a library of old videos, this can free up hundreds of gigabytes of storage.
Universal device compatibility
H.264 MP4 plays natively on every modern device: Windows PCs, Mac, iPhone, iPad, Android phones and tablets, smart TVs from Samsung, LG, Sony, and every other brand, gaming consoles (PS5, Xbox), and all web browsers. AVI fails on most of these without codec installation.
Streaming and web support
MP4 with the faststart flag enables instant progressive playback in web browsers. AVI cannot be streamed at all. If you want to embed video on a website, share via messaging apps, or upload to YouTube/Instagram/TikTok, MP4 is the only option.
Future-proofing
Codec support for Xvid and DivX is declining. Each new OS release removes more legacy codec support. Converting now ensures your videos remain playable for decades. H.264 is an ISO standard with guaranteed long-term support — it will be playable far longer than AVI codecs.
How to Convert AVI to MP4 Online
Converting AVI to MP4 with CleverUtils.com takes three steps:
- Upload your AVI file — drag and drop into the converter above, or click to browse. Maximum file size is 100 MB.
- Click Convert to MP4 — our server re-encodes your video with H.264 (CRF 23) + AAC audio at 192 kbps. The faststart flag is enabled for instant web playback.
- Download your MP4 — the converted file is ready in 30 seconds to 2 minutes depending on file size. No registration, no email required.
Note: AVI to MP4 conversion always requires re-encoding. Unlike MKV-to-MP4 (which can sometimes remux), the Xvid/DivX codecs in AVI are not compatible with the MP4 container. Re-encoding is mandatory, but the result is a smaller, better file.
AVI to MP4 Quality and Settings
Our converter uses the following FFmpeg pipeline:
- Video: H.264 (libx264), CRF 23, medium preset, YUV420p pixel format
- Audio: AAC at 192 kbps (transparent quality)
- Faststart:
-movflags +faststartfor instant web playback
At CRF 23 the extra loss from re-encoding is small and hard to see. The medium preset balances encoding speed with compression efficiency.
Interlaced sources are not deinterlaced. The converter keeps the frames as they are, so old camcorder and TV recordings keep their horizontal combing lines on motion. Deinterlace them with HandBrake (Filters tab) or FFmpeg’s yadif filter instead.
Convert AVI to MP4 with VLC or HandBrake
VLC
Open Media → Convert / Save, add the AVI, click Convert / Save, choose the profile Video – H.264 + MP3 (MP4), set a file name ending in .mp4 and click Start.
HandBrake
Open the AVI and pick a preset such as Fast 1080p30, or Fast 480p30 for SD camcorder files. On the Filters tab, set Deinterlace for interlaced footage, then choose MP4 on the Summary tab and click Start Encode.