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.wmv File Extension

Learn what a .wmv file is, which apps open Windows Media Video, how Poly supports it, and when to convert WMV to MP4 or WebM.

File extension details for .wmv

Full Support
File typeWindows Media Video file
MIME type
video/x-ms-wmv
EncodingBinary Advanced Systems Format container with synchronized video, audio, and metadata streams
Operating systemsWindows, macOS, Linux, iOS, Android
Opens withVLC media player, Windows Media Player, FFmpeg
Poly supportYes. Poly provides rich support for WMV videos when their streams can be decoded.
Indexed by PolyYes. Poly indexes filenames, supported metadata, spoken transcripts, and visual content.
Preview in PolyYes. WMV files get thumbnails, timeline previews, and in-app playback when decodable.
Poly agentYes. The Poly agent can use supported visual content, transcripts, and metadata.

What kind of file is a .wmv?

A .wmv file is a Windows Media Video file. It normally uses Microsoft's Advanced Systems Format (ASF) container and carries video encoded with a Windows Media Video codec. The conventional media type is video/x-ms-wmv, although it is not registered in IANA's current media-type registry.12

WMV is a family rather than one codec. Files may contain WMV 7, WMV 8, WMV 9, VC-1, or related profiles, often alongside Windows Media Audio. A player must understand the ASF container and each stream inside it.

ASF files begin with the 16-byte Header Object GUID 30 26 B2 75 8E 66 CF 11 A6 D9 00 AA 00 62 CE 6C. That signature identifies ASF, not WMV specifically, because .wma and .asf files can share it. Reliable identification also requires inspecting the stream descriptions.3

Renaming another video to .wmv does not convert its container or codecs. Likewise, changing a .wmv filename to .mp4 leaves the media data unchanged.

How do I open a .wmv on my computer?

On Windows, try Windows Media Player. Microsoft lists WMV among its supported file types, although playback can still depend on the codecs and protection used by a particular file.4 VLC is a practical cross-platform choice on Windows, macOS, and Linux because its published support includes ASF/WMV containers and WMV 7, 8, 9, and VC-1 video.5

On iPhone, iPad, Android, and macOS, use a maintained media app that explicitly supports ASF and the contained codecs. Native browser playback is unreliable, so convert WMV for a website instead of depending on an old plug-in.

If picture appears without sound, or sound without picture, inspect both streams. The container may be valid while one decoder is missing. DRM-protected files also require compatible software and a valid license.

Poly support for .wmv

Poly gives decodable WMV videos thumbnails, timeline previews, in-app playback, technical metadata, visual search, searchable speech transcripts, and agent understanding. Metadata can include duration, dimensions, frame rate, codecs, color information, and audio-track details.

Transcript search requires usable audio with audible speech. Silent video can still benefit from visual search. Protected, damaged, or unsupported streams may limit playback, indexing, or agent access.

History of .wmv

Microsoft moved its streaming platform under the Windows Media name in 1999. Windows Media Technologies 4.0 promoted updated compression, download-and-play media, multibit-rate streaming, and rights management.6 Later WMV generations culminated in Windows Media Video 9, which Microsoft describes as its implementation of the VC-1 standard.7

The .wmv suffix distinguishes ASF files intended to carry Windows Media video from .wma audio files and .wvx metafiles. A WVX usually points to media, while a WMV contains the timed media data itself.1

Working with .wmv and alternatives

For modern delivery, MP4 or WebM is usually easier to play across browsers and devices.

NeedPractical choiceTradeoff
Broad device playbackMP4 with H.264 and AACOlder WMV codecs usually require transcoding
Open web deliveryWebM with VP9 or AV1 and OpusTest the browsers and devices you support
Preserve the originalKeep WMV plus a modern derivativeUses more storage but retains the source

Remuxing changes only the container and preserves compatible compressed streams. Transcoding decodes and re-encodes them, which can reduce quality. Keep the original until you have checked the converted video's full duration, picture, sound, synchronization, frame rate, and metadata.

Footnotes

  1. Microsoft. File Name Extensions for Windows Media. ↩ ↩2
  2. Internet Assigned Numbers Authority. Media Types Registry. The current video registry contains no video/x-ms-wmv entry. ↩
  3. Library of Congress. WMV (Windows Media Video) File Format. Format identifiers, ASF relationships, codec versions, and signature information. ↩
  4. Microsoft Support. File Types Supported by Windows Media Player. ↩
  5. VideoLAN. VLC Features. ↩
  6. Microsoft. Microsoft Announces Beta Release of Windows Media Technologies 4.0. ↩
  7. Microsoft. About the Windows Media Codecs. ↩
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