AVI to MKV Converter

AVI vs MKV — Which Should You Convert To?

If your AVI files won't carry H.264 or HEVC cleanly, can't hold subtitle tracks, or balloon in size, MKV is the modern container that fixes all three. AVI is Microsoft's 1992 RIFF-based format; MKV (Matroska) is an open, royalty-free standard that wraps almost any codec plus unlimited audio, subtitle, and chapter tracks. Convert AVI to MKV when you want one self-contained file with embedded subtitles and modern codecs; stay on AVI only when a legacy device or editor demands it.

Side-by-side Comparison

When to Pick AVI

• A legacy DVD player, camcorder, or hardware media player only reads AVI.
• An old editing tool (early Premiere, VirtualDub) expects an AVI/RIFF input.
• You need a lossless intermediate with a codec like HuffYUV that some AVI-era pipelines still assume.
• Maximum compatibility with Windows XP-era software matters more than features.

When to Pick MKV

• You want embedded soft subtitles you can toggle, not a separate .srt file.
• Your video uses H.264 or HEVC — AVI cannot carry these reliably, MKV can.
• You need multiple audio tracks (e.g. an original language plus a dub) in one file.
• You want chapters, cover art, or the smallest container overhead for archiving.

How to Convert AVI to MKV

1. Upload Your AVI File: Drag and drop your AVI onto the page or click "+ Add Files". Add several at once to batch-convert with the same settings.
2. Set the Video Codec: Open Advanced Options. MKV defaults to H.264 video with AAC audio. Matching your AVI's existing codec keeps the re-encode in the same family; pick H.265 from the Video Codec list to shrink the file further, or HuffYUV for a mathematically lossless encode.
3. Adjust Compression or Trim (Optional): Under File Compression, choose Quality Preset (Very High is the default) or Specific file size to target an exact size. Use Trim → Time Range to export just a clip.
4. Convert and Download: Click "Convert" and save your MKV. No sign-up, no watermark. Files are uploaded over an encrypted connection, processed on our servers, and deleted automatically after a few hours.

Need maximum device compatibility instead of MKV's flexibility? Use AVI to MP4. Already have MKV files you want to play on older hardware? See MKV to MP4.

MKV Video Codec Options

The MKV defaults to H.264 video, but you can change the Video Codec in Advanced Options. Every choice re-encodes — there is no stream copy:

Frequently Asked Questions

Will converting AVI to MKV reduce quality?

Not visibly, if you keep the same codec. The conversion always re-encodes the video — there is no stream-copy rewrap — but when the output stays on the source's codec (say H.264 in, H.264 out) the default Very High preset encodes at the visually-lossless tier, so the MKV is hard to tell apart from the source. Switching to a different codec (e.g. H.265) or targeting a smaller file size trades more quality for size.

Can MKV hold the subtitles AVI couldn't?

Yes — that is one of MKV's main advantages. AVI has no native way to embed soft subtitles, so they have to live in a separate file or be burned into the picture. MKV stores selectable subtitle tracks (SRT, ASS/SSA, or PGS) inside the file, alongside multiple audio tracks and chapters.

Is MKV better than AVI for storing modern codecs?

For H.264 and HEVC, yes. AVI was designed in 1992 and does not handle compression that relies on future-frame (B-frame) data, which both H.264 and HEVC use heavily. MKV carries these codecs natively, so an H.264 file in MKV plays correctly where the same codec stuffed into AVI may stutter or fail.

Does AVI to MKV make the file smaller?

Keeping the same codec barely changes size — MKV has lower container overhead than AVI (AVI adds roughly 5 MB per hour of standard-definition video), but the real savings come from switching codecs. Switch the Video Codec to H.265 or set a Specific file size to compress; keep the source codec and the default quality preset to stay near the original size.

Why won't some devices or apps play MKV?

MKV is an open standard but never became a hardware industry default, so some older smart TVs, game consoles, and basic media players skip it. VLC, MPV, Kodi, Plex, and most current TVs handle it fine. If a device refuses MKV, convert to MKV to MP4 for the widest compatibility.

Is the MKV format still maintained?

Yes, and it is now a formal standard. The Matroska project began in December 2002, and in October 2024 the IETF published the container as RFC 9559, "Matroska Media Container Format Specification." It remains a royalty-free open standard governed by a non-profit, so there are no licensing fees to read or write .mkv files.

Which audio codec does the MKV use?

By default the audio is re-encoded to AAC, matching the H.264 video the MKV defaults to. Because Matroska can carry unlimited audio tracks, you can keep more than one language or commentary track in the same file — something AVI cannot do reliably. As with the video, the audio is always re-encoded; there is no stream-copy rewrap.

How big a file can I convert here?

There is no fixed file cap — a 700 MB DivX-in-AVI episode converts comfortably. Every conversion is a re-encode, so processing time scales with the clip's duration and resolution, and the practical limit is upload size and time over your connection. There is no sign-up or watermark on the output.