Step 1: Transfer your WMV files using the button above or by slide and deposit.
Step 2: Click the 'Convert' button to start the conversion.
Step 3: Retrieve your converted WebM files.
WMV to WebM Conversion FAQ
How do I re-encode WMV to WebM without losing video quality?
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Upload your WMV file and the converter runs a CRF-based re-encode targeting visually-lossless WebM output (CRF 18 by default, lower values = larger file / higher quality). The codec is chosen to match the WebM container — H.264 for broad-compat MP4, H.265 for size-efficient MKV, VP9 for WebM, AV1 for newer pipelines. WMV carries Microsoft’s own VC-1 or WMV3 video with WMA audio — codecs almost nothing outside Windows decodes natively. WebM is deliberately narrow: VP8 or VP9 video (AV1 more recently) with Vorbis or Opus audio, and nothing else.
My WMV footage shows comb lines on movement — will that carry into the WebM?
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It will unless you deinterlace, and WMV 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. WMV is Windows Media Video, Microsoft’s ASF-based format from the Windows XP era.
Can I add selectable subtitles once the file is WebM?
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Yes. WMV has no usable soft-subtitle track, so subtitles for WMV 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.
Why does my WMV file fail to convert to WebM?
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Almost always DRM. Some WMV files are encrypted at the bitstream level by the store or software that issued them, and an encrypted stream cannot be decoded by us or by anything else without the licence key. Files you recorded, exported or downloaded unprotected convert normally; a licensed purchase will not, and no converter can honestly promise otherwise. WMV is effectively a dead end: macOS, iOS, Android and every browser need third-party decoders, and some WMV files carry DRM that cannot be converted at all.
Will the WebM play in a browser when the WMV would not?
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Yes, and that is usually the whole reason for the conversion. A WMV 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 WMV recordings to WebM at all?
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For anything you intend to keep, yes. WMV 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.
Which video codec does the WebM output use?
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It depends on the WebM container. MP4 defaults to H.264 for the broadest playback support across phones, browsers, and Smart TVs. MKV defaults to H.265 / HEVC for roughly half the file size at equivalent quality. WebM defaults to VP9. The advanced options expose explicit codec choice if you need to override. WebM is a strict subset of Matroska that Google published in 2010 specifically to give HTML5 video a royalty-free container.
Will my audio track survive WMV to WebM conversion?
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Yes. When WMV and WebM share an audio codec (e.g. both carry AAC), audio is re-muxed with no re-encode — bit-identical. When the codecs differ, audio is transcoded to AAC / Opus / Vorbis depending on what the WebM container supports. Multi-track audio (commentary, alternate languages) is preserved.
Can I keep the original framerate when converting WMV to WebM?
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By default yes — a 24fps WMV stays 24fps in WebM; a 60fps WMV stays 60fps. If you need to change rate (e.g. interlaced 29.97 → progressive 30, or 60 → 30 for upload limits), the framerate option handles 3:2 pulldown, deinterlacing, and frame-blending in the same encode pass.
How much will the file size change going from WMV to WebM?
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Same-codec re-mux (WMV H.264 → WebM H.264 just changing container): nearly identical size. Codec change can swing dramatically: H.264 → H.265 typically halves the file at the same visual quality; VP9 is roughly comparable; AV1 cuts another 20-30% but is slower to encode.
Will the WebM file play on iPhone, Android, and Smart TVs?
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MP4 / H.264 plays natively on every modern device. MOV / H.264 plays on Apple devices and most TVs but not always on older Android. MKV needs VLC on iOS. WebM is browser-first. The advanced options include a "device compatibility" preset that picks the safest WebM codec / container for your target. WebM is a poor fit anywhere outside a browser — video editors, phones’ native galleries and Smart TVs largely ignore it.
How long does converting a 1-hour WMV video to WebM take?
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Same-codec re-mux is near-instant — 30 to 60 seconds for a 1-hour file. A full codec re-encode runs at roughly 0.3-0.7x source duration on our GPU pipeline, so a 1-hour WMV → WebM finishes in 18-40 minutes depending on resolution and target codec.
