Step 1: Provide your AVI files using the button above or by toss and let go.
Step 2: Click the 'Convert' button to start the conversion.
Step 3: Fetch your converted WebM files.
AVI to WebM Conversion FAQ
How do I convert AVI to WebM without re-encoding the video stream?
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When the AVI and WebM containers can both carry the same codec (H.264, H.265, VP9, AV1), the converter falls back to a remux: the elementary streams are copied byte-for-byte into the WebM container and only the wrapper changes. A remux of a 1 GB AVI into WebM typically finishes in 5-15 seconds with zero quality loss. AVI files predate modern codecs: expect MPEG-4 Part 2 (DivX/Xvid), Motion JPEG or raw uncompressed frames rather than H.264. WebM is deliberately narrow: VP8 or VP9 video (AV1 more recently) with Vorbis or Opus audio, and nothing else.
My AVI footage shows comb lines on movement — will that carry into the WebM?
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It will unless you deinterlace, and AVI content very often is interlaced because the format comes from the broadcast and DVD era. Interlaced frames store two half-height fields captured a fiftieth of a second apart; on a progressive-scan phone or monitor that reads as horizontal combing on anything that moves. Turn on the deinterlace option and the encoder weaves the fields into whole progressive frames before writing the WebM. AVI is Microsoft’s Audio Video Interleave, introduced in 1992 on top of the RIFF chunk format — one of the oldest containers still in circulation.
My AVI recordings are split into numbered parts — does WebM have the same limit?
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No, and that is one of the better reasons to move. The AVI container has a practical single-file ceiling that long or high-bitrate recordings run straight into, which is exactly why old captures arrive as part1, part2, part3. WebM has no equivalent limit, so the pieces can be rejoined into one continuous file. AVI has no native support for modern codecs, variable frame rate, soft subtitles or files over 4 GB without hacks, and its per-chunk overhead bloats the file.
Can I add selectable subtitles once the file is WebM?
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Yes. AVI has no usable soft-subtitle track, so subtitles for AVI content had to be burned into the picture or shipped as a separate sidecar file. WebM carries subtitles as their own selectable stream, so after conversion you can attach an SRT track the viewer can switch on, switch off or restyle.
My AVI has several audio tracks — do they all survive into the WebM?
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Not dependably. AVI stores multiple audio streams as first-class tracks, but WebM playback support past the first track is inconsistent, so most players will only ever expose one. Choose the track you actually want before converting; the others are better extracted to their own files than left in a container that hides them. AVI is trivially simple, which is exactly why ancient camcorders, capture cards, DVD ripping tools and Windows-era software all still emit it. WebM is a poor fit anywhere outside a browser — video editors, phones’ native galleries and Smart TVs largely ignore it.
Will the WebM play in a browser when the AVI would not?
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Yes, and that is usually the whole reason for the conversion. An AVI embedded in a web page either shows a broken player or forces a download, because browsers ship no decoder for it. WebM plays inline through the native HTML5 video element with no plugin and no external application. WebM plays natively in every modern browser with no plugin, no licence fee and no patent exposure, which makes it the default for web-embedded video.
Is it worth converting old AVI recordings to WebM at all?
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For anything you intend to keep, yes. AVI belongs to an earlier generation of video tooling and the software that reads it is steadily disappearing from phones, browsers and operating systems. Moving the footage to WebM now, while a clean decoder still exists, is the difference between an archive you can open in ten years and one you cannot.
Will multi-track audio survive AVI to WebM conversion?
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Yes — every audio track in the AVI (director commentary, alternate languages, descriptive audio) is preserved in the WebM when the target container supports multi-stream audio. MKV and MOV handle unlimited audio tracks; MP4 supports many but some hardware players only see track 1; WebM is capped at one Opus / Vorbis track. WebM is a strict subset of Matroska that Google published in 2010 specifically to give HTML5 video a royalty-free container.
Are subtitle tracks preserved when converting AVI to WebM?
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Soft subtitles (selectable tracks) survive when WebM can carry them: MKV holds SRT, ASS, SSA, PGS, VobSub natively; MP4 only holds mov_text (a stripped-down format). Converting an MKV with ASS styled subs to MP4 will typically downgrade them to mov_text or burn them in. Hardsubs (burned into the video) carry over regardless.
Does AVI to WebM keep chapter markers / DVD-style navigation?
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Chapter metadata transfers between AVI and WebM whenever both containers support a chapter atom (MKV, MP4, MOV). WebM stores chapters in a Matroska-compatible block, so MKV <-> WebM chapters round-trip cleanly. AVI has no chapter spec at all, so an AVI source arrives with no chapters to carry across and an AVI target cannot store the ones it was handed; add markers manually afterwards if you need them.
What about MKV attachments (fonts, cover art) when going AVI to WebM?
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MKV is the only mainstream container that stores arbitrary attached files (TTF fonts for ASS subs, JPG cover art, fan-translated PDF inserts). Going from AVI to WebM drops these attachments when WebM is not MKV — the elementary streams convert, but the attached payload stays in the source. Keep AVI as a backup if you depend on attached fonts.
Which codec does the WebM output use by default?
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The default codec is chosen to match the WebM container conservatively: MKV defaults to H.265 (HEVC) for better compression; MP4 defaults to H.264 for the widest device support; WebM defaults to VP9; AVI uses MPEG-4 ASP (DivX/Xvid lineage). Override via the advanced codec dropdown — AV1 is available for MKV / WebM where you want maximum compression and can wait through the encode.
