WMV File (.wmv): What It Is and How to Open It

The basics

What is a WMV file?

WMV was Microsoft's video format for the Windows PC era. In the late 1990s and 2000s it was how video was streamed from Windows Media servers, sold by online video stores, exported from Windows Movie Maker and attached to emails. You'll still find WMV files in old archives, training material, conference recordings and backups from that time.

Strictly, a .wmv file is two things. The container is ASF, the Advanced Systems Format, originally called the Advanced Streaming Format, which Microsoft and several partners published as a draft in 1997. Inside it is video compressed with a Windows Media Video codec, and usually sound in Windows Media Audio. Microsoft's own rule is that ASF files with Windows Media content are named .wmv (video) or .wma (audio only), and ASF files with other content can use .asf.

In short

WMV still plays on Windows and in VLC, but no browser supports it. For sharing or putting video on the web, convert it to MP4.

Anatomy

What's inside a WMV file

A WMV file is an ASF file: a short list of objects, each starting with a 16-byte GUID that says what it is and an 8-byte size. Numbers are little-endian. Below is the object tree of a 2-second, 320×240 WMV we made for this page with FFmpeg (WMV 8 video, WMA stereo audio), read from the file byte by byte. It isn't offered for download.

tiny.wmv (object tree, with key bytes in hex)

tiny.wmv: 2 s, 320×240 WMV 8 video + WMA stereo, 183,467 bytes

offset    object                        size      contents
0         Header Object                 919       7 child objects
          30 26 B2 75 8E 66 CF 11 A6 D9 00 AA 00 62 CE 6C
          97 03 00 00 00 00 00 00 · 07 00 00 00 · 01 02
30          File Properties             104       file size, 57 packets of
                                                  3,200 bytes, preroll 3,100 ms
134         Header Extension            156       holds a Metadata object
290         Content Description         78        title "Test clip",
                                                  author "Ada Example"
368         Extended Content Descr.     182       name/value tags,
                                                  WM/EncodingSettings
550         Stream Properties           133       stream 1: video,
                                                  320×240, FourCC "WMV2"
683         Stream Properties           114       stream 2: audio, tag 0x0161,
                                                  2 ch, 44.1 kHz, 64 kbps
797         Codec List                  122       "wmv2", "Windows Media
                                                  Audio V8"
919       Data Object                   182,450   57 packets
          36 26 B2 75 8E 66 CF 11 A6 D9 00 AA 00 62 CE 6C
969         packet 1                    3,200
            82 00 00 · 01 5D                      error correction, flags
            00 00 00 00 · 2E 00                   send at 0 ms, lasts 46 ms
            82                                    2 payloads follow
            02 01 00 00 00 00 08 …                stream 2, media object 1,
            73 01 00 00 1C 0C 00 00               371 bytes, shown at 3,100 ms
            …                                     then video payloads
183,369   Simple Index Object           98        keyframe index for seeking
          90 08 00 33 B1 E5 CF 11 89 F4 00 A0 C9 03 49 CB

130 26 B2 75 8E 66 CF 11 …
The Header Object GUID
Every ASF file, so every WMV and WMA, starts with these 16 bytes: the GUID 75B22630-668E-11CF-A6D9-00AA0062CE6C, with its first three fields stored back to front, as Windows stores GUIDs. File-type detectors look for this exact sequence.
297 03 00 00 00 00 00 00 · 07 00 00 00 · 01 02
Size, count and two reserved bytes
An 8-byte size (0x397 = 919 bytes), the number of objects inside the header (7), and two reserved bytes that are always 01 02. The header is the only top-level object that contains other objects.
3File Properties
File-wide facts
The file size, the number of data packets (57), their size (always the same within a file: 3,200 bytes here), the maximum bit rate and a preroll: how many milliseconds a player should buffer before it starts. Here it's 3,100 ms, and every timestamp in the file is shifted by that amount.
4Content Description
Title and author
Five fixed text fields in UTF-16: title, author, copyright, description and rating. Newer tags, such as album or genre, go in the Extended Content Description as name/value pairs like WM/AlbumTitle.
5Stream Properties … "WMV2"
One object per stream
Each stream has a number (1 to 127), a type GUID (video or audio) and codec details. For video that's a Windows BITMAPINFOHEADER whose compression FourCC names the codec: WMV2 is WMV 8. For audio it's a WAVEFORMATEX with a format tag: 0x0161 is Windows Media Audio Standard.
6Codec List
Human-readable codec names
Names and descriptions of the codecs, so a player can tell you what's missing. It's informative only; players decode using the Stream Properties.
736 26 B2 75 …
The Data Object
Its GUID differs from the header's only in the first byte. After a file ID and the packet count come the packets themselves, all the same size, so a player or server can jump to any packet by multiplying. A partly downloaded file still plays up to where it stops.
882 00 00 · 01 5D · …
Inside a packet
A few bytes of error-correction data and flags, a send time and a duration, then payloads. Each payload says which stream it belongs to, which media object (video frame or audio block) it's part of, where in that object it goes and when it should be shown. Large frames are split across packets this way.
990 08 00 33 …
The Simple Index Object
Optional: a table of times and the packets holding the nearest keyframe, which makes seeking quick. Files without it still play, but jumping ahead can be slow or impossible in some players.

Under the hood

How the ASF container works

ASF was designed for streaming over networks of the 1990s, and it shows in the structure:

Three top-level objects. A Header Object with everything about the file and its streams, a Data Object with the media, and an optional index. Every object starts with a GUID and a size, so a reader can skip anything it doesn't recognise.
Fixed-size packets. All packets in a file are the same length. A server can send them at a steady rate, and a player that loses one knows exactly where the next begins.
Interleaved, time-stamped payloads. Audio and video pieces are mixed in the order they're needed, each with its stream number and presentation time.
Many streams. A file can hold several audio streams (for languages), several video streams at different bit rates for different connection speeds, and a script command stream for captions or events.
Compression-agnostic. ASF doesn't care what codec made the data. Microsoft's codecs were the usual ones, but other codecs can be stored too.

ASF was Microsoft's successor to the RIFF-based AVI format. Unlike AVI, each payload carries its own timestamp, so variable frame rates and seeking within streams work. The specification is published by Microsoft; the current revision, 01.20.03, dates from December 2004.

Codecs

WMV 7, 8, 9 and VC-1: which codec is in the file

The video stream's FourCC code tells you which generation of the codec made it. ffprobe file.wmv shows it, and so does VLC under Tools → Codec Information.

Video codecs found in WMV files
FourCC	Codec	Notes
`WMV1`	Windows Media Video 7	The oldest version you're likely to meet.
`WMV2`	Windows Media Video 8	The next version. FFmpeg can still write it.
`WMV3`	Windows Media Video 9	The codec that became the Simple and Main profiles of VC-1. The most common in later WMV files.
`WVC1`	WMV 9 Advanced Profile (VC-1)	Fully VC-1 compliant, with interlaced video. `WMVA` is an earlier, not fully compliant version.
`MSS1`, `MSS2`	Windows Media Screen	For screen recordings: flat colours and sharp text.

VC-1 is Windows Media Video 9 turned into a public standard: SMPTE 421M, published in 2006. It had a life beyond WMV. HD DVD and Blu-ray Disc both made VC-1 one of their mandatory video codecs, so some Blu-ray films are encoded in it, and it was the official video codec of the Xbox 360. Outside a WMV, VC-1 can sit in other containers such as the MPEG transport streams on discs, or in MKV.

Windows Media codecs can also be stored in an AVI file, and some old AVIs use them. The codec, not the extension, decides what a player needs.

Protection

DRM-protected WMV files

Online video stores and download services of the 2000s often protected their WMV files with Windows Media DRM. In a protected file:

The media is encrypted with a key. The header contains a Content Encryption or Extended Content Encryption object that says so.
The key isn't in the file. To play it, a player has to get a separate licence that contains the key and the rights the seller granted: how long you can watch, on how many devices, whether you can burn it.
The licence is stored on the computer that obtained it, not in the file.

That's why a protected WMV that played for years can stop working after you move it to a new PC or reinstall Windows: the licence didn't come along, and the service that issued it may no longer exist. VLC doesn't play DRM-protected files at all. Microsoft now marks Windows Media DRM as deprecated and points developers to its successor, PlayReady.

If a file asks for a licence

Only the original seller can issue a new licence. If the service is still running, sign in on the authorised PC with Windows Media Player Legacy. If not, the content has to be obtained again. Be wary of tools or web pages that promise to strip protection or to fetch a missing licence for you: they're a common way to spread malware.

To check whether a file is protected, run ffprobe file.wmv: for a protected file FFmpeg warns DRM protected stream detected, decoding will likely fail!. Windows Media Player Legacy asks for a licence instead.

How to play

How to play a WMV file on Windows, Mac, Linux and phones

Windows 10 and 11: Windows includes WMV, VC-1 and WMA decoders, so both players can open ordinary WMV files. The Media Player app is the current one. Windows Media Player Legacy, the classic player, is still included in clean installs of Windows 10 and offered as an optional feature in some editions of Windows 11 (Settings → System → Optional features → View features). It's the one to use for DRM-protected files.
macOS: VLC or IINA, both free. QuickTime Player can't open WMV. Flip4Mac, the plug-in that once added Windows Media to QuickTime, was discontinued years ago, and Apple dropped the QuickTime 7-era plug-in system it relied on.
Linux: VLC or mpv. Both use FFmpeg's decoders, which handle WMV 7, 8 and 9 and VC-1.
Phones and tablets: VLC for Android and iOS plays WMV; the built-in players usually don't.
Inspect it: ffprobe file.wmv lists the streams, codecs and tags; MediaInfo shows the same in a window.

Legacy vs the new Media Player

Microsoft recommends the Media Player app for modern video. Both play unprotected WMV files. For an old DRM-protected file, use the Legacy player, which was built around Windows Media DRM.

On the web

Why browsers won't play WMV

No current browser plays WMV in a <video> element; open a .wmv link and the file downloads. Browsers support MP4, WebM and a few other containers, and ASF was never one of them. Even the codecs are missing: browsers don't ship WMV or WMA decoders, so moving the streams into an MP4 wouldn't help.

In the 2000s, web pages played WMV through the Windows Media Player browser plug-in, and on Macs through Flip4Mac. Browsers have since removed plug-in support entirely. To put a WMV on a web page today, convert it:

terminal

# WMV to MP4 (H.264 + AAC), ready for the web
ffmpeg -i input.wmv -c:v libx264 -crf 20 -c:a aac -b:a 160k -movflags +faststart output.mp4

# check what's inside first
ffprobe input.wmv

WMV video always has to be re-encoded, because no other common format accepts WMV or VC-1 video for the web. HandBrake, a free app with presets, does the same thing without the command line.

Related formats

WMV vs MP4, AVI and MKV

	WMV (ASF)	MP4	AVI	MKV
Owner	Microsoft	ISO/IEC standard	Microsoft	Open (Matroska)
Typical codecs	WMV 7–9, VC-1, WMA	H.264, HEVC, AV1, AAC	Xvid, Motion JPEG, DV, MP3	Almost anything
Frame timestamps	Yes	Yes	No	Yes
Plays in browsers	No	Yes, everywhere	No	Chrome, Edge, Firefox
Good for today	Reading old files	Sharing and the web	Reading old files	Archiving, several tracks

Troubleshooting

Why won't my WMV play? Common problems and fixes

Symptom	Usual cause	Fix
Asks for a licence, or says the file is protected	Windows Media DRM, and no licence on this computer.	Play it on the computer that bought it, or get it again from the seller. See the DRM section above.
Won't open on a Mac	macOS has no Windows Media support.	Use VLC or IINA, or convert to MP4.
Downloads instead of playing in the browser	Browsers don't support ASF or the Windows Media codecs.	Convert to MP4 with FFmpeg or HandBrake.
Sound but no picture, or the reverse	A codec the player lacks, such as Windows Media Screen (`MSS1`, `MSS2`) in an older player.	Try VLC, or check the streams with `ffprobe`.
Can't skip ahead	The file has no index, often because a recording stopped early.	Remux it: `ffmpeg -i in.wmv -c copy out.wmv` writes a new index.
Blocky picture at a low resolution	Encoded at a low bit rate for 2000s internet connections.	Nothing can restore the detail; converting won't improve it.

Security

Is a WMV file safe?

"You need a codec" or "get a licence here". A video, or a page offering one, that tells you to install a codec or a player to watch it is a classic malware trick. VLC plays every unprotected WMV as it is.
Script commands. ASF can carry a script command stream, which players such as Windows Media Player could use to show captions or open a web page at a set time in the video. Be suspicious of any video that opens a page asking you to download something.
Disguised programs. video.wmv.exe is a program. Turn on file name extensions in File Explorer so you see the real one.
Old software. A WMV can't run code by itself, but crafted files can target bugs in old players and codec packs. Keep your player updated and remove codec packs you don't need.

Sample files

There are no sample WMV files on this page. To make one for testing, run ffmpeg -f lavfi -i testsrc2=size=640x360:rate=30 -f lavfi -i sine=frequency=440 -t 5 -c:v wmv2 -b:v 1M -c:a wmav2 -b:a 128k test.wmv; FFmpeg writes WMV 8 video with WMA audio, but it can't encode WMV 9 or VC-1.

Put it online

Have a WMV file? Give it a link.

Drop a WMV on 99helpers and it gets its own address to send instead of a large attachment. Browsers can't play WMV, so the file downloads when the link is opened; to have it play in the browser, convert it to MP4 first.

Put a WMV online

Questions

WMV files, frequently asked

What is a WMV file?

A Windows Media Video file: video compressed with one of Microsoft's Windows Media codecs, stored in the ASF container, usually with Windows Media Audio sound. It was a common video format on Windows PCs in the 2000s.

How do I play a WMV file on a Mac?

Use VLC or IINA, both free. QuickTime Player can't open WMV, and Flip4Mac, the old QuickTime plug-in for Windows Media, is discontinued.

How do I convert WMV to MP4?

Use HandBrake, or run ffmpeg -i input.wmv -c:v libx264 -crf 20 -c:a aac -movflags +faststart output.mp4. The video has to be re-encoded, because MP4 players don't decode WMV.

Does Windows 11 play WMV files?

Yes. Windows includes the WMV, VC-1 and WMA decoders, so the Media Player app plays ordinary WMV files. Windows Media Player Legacy is available as an optional feature in some editions, and is needed for old DRM-protected files.

Why won't my WMV play in Chrome?

No browser supports the ASF container or the Windows Media codecs. The file downloads instead. Convert it to MP4 to play it in a browser.

Is WMV the same as VC-1?

Not quite. WMV is the file format; VC-1 is a codec. VC-1 is Windows Media Video 9 standardised as SMPTE 421M, and it's found in WMV files and on some Blu-ray discs.

Why does my WMV ask for a licence?

It's protected with Windows Media DRM. The decryption key comes in a licence from the seller, stored on the computer that downloaded it. Without that licence it won't play, and only the seller can issue a new one.

Is WMV still used?

Rarely for new video, which is almost always made as MP4 now. WMV survives in archives and in older corporate and training material.

Related formats

Other file types explained

WMA file MP4 file AVI file MKV file MOV file FLV file All file types

Keep going

Host a WMV file

Put a WMV online at its own address for others to download.

Share a WMV file

Send a video as a link instead of an attachment.

Hosting guides

How to put different kinds of files online.

Sources

Last reviewed 27 October 2026.