Xvid to MKV

How to Convert Xvid to MKV Online

1. Upload Your Xvid File: Drag and drop your .avi (Xvid-encoded) video onto the page or click "Add Files." Batch uploads are supported, so you can repackage an entire DivX/Xvid collection in one job.
2. Pick Quality Preset or Bitrate Mode: The default is "Very High (Recommended)," which re-encodes to a modern codec at near-source quality. Switch to Constant Quality (CRF) for the best size-to-quality ratio (CRF 18 = visually lossless, CRF 23 = sane default), Constant Bitrate for predictable streaming targets, or Specific file size when you need to fit a fixed disk or upload cap. Variable Bitrate is the right pick for archive-grade results when you don't care about exact size.
3. Set Resolution and Trim (Optional): Under Video Resolution, choose Keep original to preserve the source pixels, pick a Preset Resolution (1080p, 720p, 480p), drop to a Resolution Percentage (50%, 75%), or set custom Width x Height. Under Trim, switch from Unchanged to Time Range and enter a start time and duration to cut out a clip.
4. Convert and Download: Click Convert. Files are uploaded over an encrypted connection, processed on our servers, and deleted automatically after a few hours — no sign-up, no watermark, never shared. Each output .mkv downloads individually, or grab the lot as a zip.

Why Convert Xvid to MKV?

Xvid is a free MPEG-4 Part 2 (Advanced Simple Profile) codec released in 2001 and still maintained — its last stable release was 1.3.7 in December 2019. It almost always ships inside an AVI container, a 1992 Microsoft format with a rigid one-video-one-audio structure, no native subtitle track, no chapter markers, and no error recovery. MKV (Matroska), released December 6, 2002, is a royalty-free open container that fixes every one of those limitations and is now the de facto standard for media-server libraries.

• Add multiple audio tracks — Matroska can hold an unlimited number of audio streams. Pack the original English dub, a foreign-language track, and director's commentary into a single .mkv instead of juggling three AVIs.
• Embed subtitles instead of sidecar .srt files — Matroska supports embedded SRT, ASS/SSA, PGS, and VobSub. Plex and Kodi let viewers toggle between embedded subs without external file management.
• Plex-friendly libraries — Plex's official supported-formats list calls out MKV; AVI is flagged as legacy with playback-stuttering reports for Xvid streams. Repackaging into MKV reduces transcoding pressure on your server.
• Chapter markers — Insert chapter points so viewers can skip to scenes the way they would on a DVD or Blu-ray. AVI has no chapter spec at all.
• Error recovery and repair — Matroska's EBML structure is designed so a corrupted byte range only affects nearby frames; truncated AVIs frequently become unplayable.
• Future-proof archive container — MKV is an open standard; the spec is freely published and royalty-free for private and commercial use, unlike codecs and containers tied to MPEG-LA pools.

Xvid (AVI) vs MKV (Matroska) — Container Comparison

Codec Choice — What Goes Inside the MKV

MKV is a container, not a codec, so converting Xvid → MKV always involves a codec decision. Use this guide to match the codec to your goal.

Frequently Asked Questions

Will the conversion re-encode my video, or just remux?

The default Very High preset re-encodes to a modern codec (typically H.264) for the broadest compatibility. If you want a true lossless remux that preserves the original Xvid stream byte-for-byte, choose the DivX/Xvid (MPEG-4 ASP) codec under Advanced Options — that path simply moves the existing stream into the Matroska container without recompression. Remuxing is faster and visually identical to the source; re-encoding is slightly slower but yields a more universally playable file.

Why does my Xvid AVI play badly on Plex but the same content in an MKV plays fine?

Plex's official supported-formats documentation lists MKV as a first-class container and AVI as legacy. The Plex community has long reported stuttering on Xvid-in-AVI streams that disappear once the same codec is repackaged into MKV. The codec data is identical — the AVI container's interleaving and lack of robust seeking is the issue, not the Xvid video itself.

Can I add multiple audio tracks or subtitle files during conversion?

The xconvert browser tool focuses on single-input conversion, so multi-track muxing isn't part of this workflow. After converting to MKV here, you can drop the result into MKVToolNix's GUI (free, open source) to add additional audio tracks, embed .srt/.ass subtitle files, and write chapter markers without re-encoding anything.

Should I pick H.264 or H.265 (HEVC) for the MKV output?

Pick H.264 for maximum compatibility — every Plex client, smart TV from the last decade, browser, and phone plays it natively. Pick H.265 if file size matters and you control the playback device. H.265 is roughly 30-50% smaller than H.264 at the same visual quality, but older Roku, Fire TV stick, and 2014-era smart TVs may force a CPU transcode on the server. Plex's hardware transcoder added broader HEVC support in early 2025, easing this on modern installs.

What's the best CRF value for converting old Xvid rips?

CRF 20-22 is the practical range. Xvid sources are usually already lossy and often capped around 480p or 720p, so going lower than CRF 18 wastes bits encoding compression artifacts. CRF 23 (libx264 default) is fine for casual viewing; CRF 20 keeps a clean archive copy at modest size. Below CRF 18, you're encoding the noise.

Does converting Xvid to MKV improve quality?

No conversion can add detail that isn't in the source. The point of converting Xvid → MKV is container-level: better track support, chapter markers, embedded subtitles, more reliable seeking, and broader media-server compatibility. If you re-encode to H.265 you save space; if you remux you preserve the exact source quality. Either way, no upscaling magic happens to the underlying frames.

Will the file get larger after converting to MKV?

Usually no, often slightly smaller. A pure remux changes only a few bytes of container overhead. Re-encoding the Xvid stream to H.264 at CRF 22 typically produces a similar-or-smaller file because modern H.264 encoders are more efficient than the 2001-era Xvid implementation. Re-encoding to H.265 at CRF 22 can shrink the result by 30-50%.

What plays MKV on Windows, Mac, and TVs?

Windows 10 and 11 play MKV natively in Movies & TV. macOS users can use VLC, IINA, or Infuse. On TVs, virtually all 2017+ smart TVs (LG webOS, Samsung Tizen, Sony Android TV, Roku TV) handle MKV via USB or DLNA. For media-server playback, Plex, Jellyfin, Kodi, Emby, and Infuse all treat MKV as the preferred container.

How is this different from just renaming .avi to .mkv?

Renaming the extension does nothing — the file is still an AVI container with AVI-specific byte layout, and most players will reject it or fall back on extension-mismatch handling. A real conversion either remuxes the stream into a proper Matroska EBML structure or fully re-encodes it. Both paths produce a valid .mkv with full seeking, track flexibility, and player compatibility.

For related repackaging workflows, see Convert Xvid to MP4, Convert AVI to MKV, Convert MKV to MP4, or Compress MKV once your library is unified.