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Supports: MKV
If a device or program refuses to open your MKV, converting to AVI is usually about reach, not quality: AVI is older and almost universally playable on Windows, while MKV is the more capable modern container. The short version — convert to AVI when you need a stubborn legacy player, set-top box, or editor to accept the file; stay on MKV (or move to MP4) when you want subtitles, chapters, or multiple audio tracks to survive. Because AVI's container is server-transcoded here, you also get to re-pick the video and audio codec on the way out.
| Property | MKV (Matroska) | AVI (Audio Video Interleave) |
|---|---|---|
| Introduced | Announced December 2002; standardized as RFC 9559 in 2024 | Microsoft, November 1992 (Video for Windows) |
| Developer / governance | Open standard, royalty-free (Matroska non-profit) | Microsoft, RIFF-based |
| Multiple audio tracks | Yes, unlimited | Possible but poorly supported by many players |
| Subtitle tracks | Yes, soft subtitles + fonts embedded | No native attachments — subtitles must be burned in or shipped separately |
| Chapters / menus | Yes | No |
| Codec flexibility | Codec-agnostic (H.264, H.265, AV1, VP9, etc.) | Best with older codecs; struggles with B-frame codecs like H.264/H.265 |
| Typical file size | Smaller with modern codecs | Often larger; weaker compression options |
| Large-file handling | Filesystem-limited | Original AVI capped near 2 GB; OpenDML (AVI 2.0, 1996) lifts it, but support varies |
| Best for | Archiving, multi-track movies, HD/4K | Legacy Windows players, older editors, hardware that predates MKV |
Usually yes. AVI cannot natively carry soft subtitles, embedded fonts, or chapters, and most players read only one audio track from an AVI. The converter keeps the primary video and audio stream; if your MKV has multiple languages or soft subs you want to keep, convert to MP4 or keep the file as MKV instead.
It depends on the codec, not the container swap itself. Re-encoding from one codec to another is lossy, so picking a higher bitrate or the Very High quality preset preserves more detail. Choosing H.264 inside the AVI keeps quality closer to the source than older codecs like MPEG-4 or Xvid, though some very old players only accept the older codecs.
AVI's older codec options and weaker compression often produce a bigger file at the same visual quality than a modern MKV does. If size matters, raise the compression in the File Compression section or set a Specific file size — or skip AVI and use MKV to MP4, which keeps files smaller with H.264 or H.265.
For the broadest reach on older Windows machines, MPEG-4 or Xvid inside AVI is the safest bet, since those decoders shipped widely for years. Choose H.264 only if you know the target player supports it in an AVI container — AVI was not designed around the B-frames that H.264 and H.265 rely on, so some legacy players stutter on it.
The original AVI format had a roughly 2 GB ceiling because of a signed-integer index; the OpenDML extension (AVI 2.0, 1996) raised it, but not every player honors OpenDML. For very long videos destined for old hardware, trim the clip with the Time Range option or keep it as MKV, which is limited only by your filesystem.
Your files are sent over an encrypted (TLS) connection, processed on our servers, and deleted automatically a few hours after conversion. There is no sign-up, the output carries no watermark, and files are never shared or made public. In our testing, a 1080p MKV with one audio track converts to a playable AVI without any manual codec tweaks beyond the defaults.