Convert MKV to AVI Online
Repackage or re-encode a Matroska video as an AVI file for software or devices that insist on .avi. Most MKVs come out as H.264 video with AAC audio, which modern players handle but DivX-only DVD players usually do not.
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MKV vs AVI, and What This Converter Does
MKV (Matroska) is an open, flexible container: one file can hold several audio languages, soft subtitles, chapters and even attached fonts, around almost any codec. AVI is Microsoft's container from the early 1990s. It handles one video stream and its audio well but has no standard way to store soft subtitles or chapters, and it predates modern codecs such as H.265 and VP9. Asking for AVI usually means some program, capture tool or player accepts nothing else.
MiConvert first tries to move the existing streams into an AVI without re-encoding, which is fast and lossless. That works when the MKV already holds AVI-friendly codecs, such as MPEG-4 Part 2 video (Xvid or DivX) with MP3 or AC3 audio. It fails for H.264, which Matroska stores in a layout AVI can't take directly, and for Opus audio. In those cases the converter re-encodes with FFmpeg: H.264 video through x264 at its veryfast preset, with 8-bit 4:2:0 pixels and an even width and height, plus AAC audio. Because H.264 is so common in MKV files, re-encoding is the usual path.
Only one video track and one audio track make it into the AVI. FFmpeg picks them automatically, and for audio it takes the track with the most channels, which may not be the language you wanted. Subtitles, chapters and attached fonts are left out. Re-encoding keeps the resolution and frame rate, but it is a lossy generation, so expect a small quality loss compared with the MKV.
Be clear about why you need AVI. The extension alone doesn't make a file play on an old DVD player or TV: those devices typically decode MPEG-4 Part 2 (DivX or Xvid) video rather than H.264, and this converter does not produce DivX or Xvid. The H.264 AVI it makes plays in VLC, MPC-HC and most current software. If your MKV holds H.265/HEVC or VP9 video, that stream is copied into the AVI unchanged, and since AVI has no standard way to signal those codecs, many players won't open the result; convert that MKV to MP4 instead.
How to Convert MKV to AVI
- Check what is inside the MKV with MediaInfo or VLC's codec information window. H.264 means a re-encode to H.264 + AAC, Xvid or DivX means a quick stream copy, and HEVC or VP9 means MP4 is the better target.
- If the file has several audio languages, only one will survive. Remux the MKV first so the language you want is the only audio track, or the one with the most channels.
- Upload the MKV. The size ceiling is 50 MB as a guest, 100 MB with a free account, 200 MB on Plus and 1 GB on Pro, so full-length movies usually need a paid plan.
- Convert. A stream copy finishes quickly; a re-encode takes longer and grows with the video's length and resolution. Each encoding pass is stopped after 30 minutes, so very long high-resolution files may not finish.
- Download the AVI and test it on the actual device or program before deleting the MKV.
How the MKV to AVI Converter Behaves
- Lossless stream copy when the codecs already fit AVI
- Automatic H.264 + AAC re-encode when they don't
- Re-encoded video uses even dimensions and standard 8-bit color that decoders accept
- Original resolution and frame rate retained
- One video and one audio track, chosen automatically
- Also accepts MP4, MOV, WebM, FLV and WMV uploads for AVI output
Video Tutorial
Watch this step-by-step tutorial to learn how to convert MKV files to AVI format online for free using MiConvert.com. No software installation required.
MKV to AVI FAQ
Will the AVI play on my old DVD player or TV?
Only if the device supports H.264 inside AVI, which many older DivX-certified players do not. This converter outputs H.264 + AAC, or copies the original streams, rather than DivX or Xvid. Check the video codecs listed in your device's manual.
Are subtitles kept?
No. Soft subtitle tracks from the MKV are not written to the AVI. Keep the subtitles as a separate .srt file next to the AVI for players that load them, or burn them into the picture with a desktop editor before converting.
Does converting MKV to AVI lose quality?
When the streams are copied, no. When the video is re-encoded to H.264 there is a small generational loss, as with any lossy re-encode. The resolution and frame rate do not change.
Which audio track ends up in the AVI?
One track, chosen by FFmpeg's default rule: the audio stream with the most channels, with ties going to the first. A 5.1 main track would win over a stereo commentary, for example.
My MKV is H.265/HEVC. Should I use this?
No. HEVC is copied into the AVI as is, and AVI has no standard identifier for it, so most players can't decode the result. Use MKV to MP4 instead, which always re-encodes the video to H.264.
Can I convert a whole movie?
Only if the file fits your plan's size limit and the encode finishes within 30 minutes. A full-length 1080p film is often bigger than 1 GB, the Pro plan's ceiling, so long movies frequently won't fit.
How long are my MKV and AVI files stored?
The uploaded MKV is wiped once the job ends. Grab the AVI within about four hours; a cleanup job deletes converted files after that window.