Convert MKV to AVI Online
Convert Matroska MKV to legacy AVI format. Free, in your browser, no file uploads.
.mkv · up to 100 MB
What you can do
MKV to AVI: Matroska to the universal format for legacy hardware
Legacy media centers
H.264+MP3 AVI is compatible with Windows XP/Vista-based players, Kodi on old ARM hardware, and first-generation HTPC boxes.
100% private
Your video never leaves your device. No servers, no usage limits.
Anime and movies
Convert anime and film collections stored in MKV to AVI for portable players without Matroska support.
Car infotainment
Pre-2018 vehicle entertainment systems read H.264 AVI from USB better than any other modern format.
How it works
Three steps, no hassle
Upload your MKV file
Drag or select your .mkv file. No signup required. Up to 2 GB.
Browser-side processing
Video and audio are re-encoded to H.264+MP3 inside an AVI container with OpenDML extension, entirely on your device.
Download your AVI
Compatible with car infotainment systems, portable DVD players, legacy media centers, and DVD authoring software.
FAQ
Got questions?
MKV (Matroska, released in 2002) is the preferred universal container for storing movies and anime with multiple audio tracks, subtitles, and chapters. However, a vast installed base of hardware does not support it: vehicle infotainment systems made before 2018, portable DVD players with USB input, digital photo frames with video capability, and media centers based on Windows XP or Vista using Windows' internal decoder. For all these devices, AVI with H.264 is the most compatible video format available.
MKV can contain multiple audio tracks (e.g., Japanese, English, Spanish) and subtitle tracks in ASS, SSA, or SRT format. When converting to AVI, the AVI container only supports a single audio track and does not support selectable text subtitles. The conversion extracts the first active audio track and re-encodes it to MP3. Subtitles are discarded unless they are 'burned in' (hardcoded) onto the video before conversion, which requires desktop tools like Handbrake or FFmpeg with the 'subtitles' filter.
Conversion involves re-encoding (not a lossless remux), so there is some quality loss going from H.264 to H.264 again. However, with a CRF (Constant Rate Factor) of 18–22 in the re-encoding, the visual difference is imperceptible on screens up to 65 inches. Anime in particular benefits from H.264 encoding thanks to its low-motion shots and flat backgrounds, which the encoder compresses very efficiently. For best results, use the H.264 'High' profile rather than 'Baseline' or 'Main'.
MP3 (MPEG-1 Audio Layer III, WAVEFORMATEX tag 0x0055) is used instead of AAC because the original 1992 AVI specification defines audio through WAVEFORMATEX, and AAC support in AVI (tag 0xFF or 0xA106) is inconsistent in legacy hardware players. Car infotainment systems, portable DVD players, and digital photo frames recognize MP3 in AVI universally, while AAC in AVI frequently causes silence or errors in these devices. In modern software players like VLC, both work correctly.
Yes. Kodi (formerly XBMC) has supported AVI with H.264 since version 9 (2009), and Plex Media Server since 2012. On old hardware with Atom processors or ARM Cortex-A8 (such as the first-generation Apple TV, Raspberry Pi 1, or nettop-based media centers with NVIDIA ION chipsets), H.264 in AVI decodes correctly via hardware or software, while H.265/HEVC may not be available for hardware decoding, causing lag or stuttering. AVI with H.264 Baseline profile is the most compatible format for these devices.
For most hardware players manufactured between 2005 and 2015, AVI has broader compatibility than MP4. Although MP4 (MPEG-4 Part 14) is technically superior and more modern (2001), many portable DVD players and first-generation infotainment systems have buggy MP4 parsers that fail with certain H.264 profiles or AAC audio in MP4, while their AVI support is more robust. However, for hardware made since 2016, MP4 is usually the preferred format. If compatibility with very old hardware is critical, AVI is the safer choice.
Convert MKV to AVI: bridging Matroska to the legacy world
MKV (Matroska Video), released under a free license by Steve Lhomme and the Matroska.org team in 2002, is the most flexible multimedia container available today: based on EBML (Extensible Binary Meta Language), a binary derivation of XML designed specifically for audiovisual media, it supports an unlimited number of video, audio, subtitle, and metadata tracks within a single file. The EBML specification defines elements through variable-length identifiers (VINTs), allowing future extensions without breaking compatibility with earlier parsers. MKV is the de facto standard container for anime fansubbing, Blu-ray rips, and high-definition movie distribution in internet communities, precisely because it can encapsulate H.264 or H.265 video, multiple audio languages in DTS, AC-3, or AAC, and subtitles in ASS/SSA format with custom fonts and karaoke effects. AVI (Audio Video Interleave), by contrast, is a Microsoft container introduced in November 1992 as part of Video for Windows 1.0 for digital video playback on Windows 3.1, with a radically simpler RIFF (Resource Interchange File Format) architecture: 'hdrl', 'movi', and 'idx1' blocks, with no native support for multiple audio tracks or text subtitles. The need to convert MKV to AVI stems directly from this difference: while MKV is the ideal format for storing and distributing rich content, AVI remains the most universally supported format on specialized hardware that was never updated to support modern containers.
The technical process of converting MKV to AVI necessarily involves a full re-encoding of video and audio, not a simple remux. This is because AVI and MKV have incompatible indexing architectures: MKV uses a seekpoint index at the EBML cluster level, while AVI uses the 'idx1' block with 32-bit offsets (or 'indx' blocks with 64-bit offsets in OpenDML). Although it is technically possible to embed H.264 without re-encoding in AVI (a process called 'direct stream copy'), this requires that the H.264 stream from the MKV be compatible with the profile and level expected by the target player, and that the original MKV audio be MP3 or AC-3 (the only audio codecs with universal support in AVI). In practice, typical anime or movie MKVs have AAC or DTS audio that is not compatible with legacy AVI, so audio re-encoding to MP3 is always necessary. For video, re-encoding to H.264 (using the 'High' profile, level 4.1 for 1080p, with a CRF between 18 and 22) produces results virtually indistinguishable from the original at resolutions up to 1080p. The OpenDML extension (AVI 2.0, Matrox 1996 specification) is essential for files larger than 2 GB, common with 1080p movies or high-resolution anime episodes.
In the 2025 consumer ecosystem, the installed base of hardware that requires AVI is broader than it might seem. The first segment is vehicle infotainment systems: manufacturers like Toyota, Honda, Nissan, Hyundai, and Kia produced between 2008 and 2018 tens of millions of units with head units that read from USB exclusively in AVI (in some cases also MP4, but with limited codec support). Owners of anime and MKV content who want to play it in their cars without investing in a new head unit or a CarPlay/Android Auto adapter find in MKV→AVI conversion their most direct solution. The second segment is portable DVD players with USB input: although the market for these devices is declining in developed markets, they remain popular in emerging markets and in households with children, and virtually all of them read AVI with H.264 or MPEG-4. The third segment is anime collectors and archivists: many fansubs from the 2003–2010 era were originally in AVI (with Xvid+MP3 or DivX+MP3), and converting modern MKV versions to AVI allows archiving them in the same historical format of the fandom, maintaining consistency in the collection. The fourth segment, more technical, is legacy software developers: video editing tools, surveillance systems, and industrial software based on Windows XP or Windows 7 (which still represent a significant fraction of industrial machines in 2025) frequently only support AVI as input. Convertir.ai performs the entire process in the browser without transmitting the file to any external server.