A practical reference for common Windows media files. Newer and higher-interest formats are listed first, followed by established and legacy formats that still appear in downloads, cameras and media archives.
A file extension does not always tell you which codec is required. MKV, MP4, MOV, WebM and AVI are containers that can hold different video and audio streams. If a file will not play, identifying the codec inside it is usually more useful than searching for a codec based only on the extension.
These formats and codecs account for many current playback questions, particularly around 4K, HDR, streaming, phones, cameras and downloaded video.
Common use: Usually stored inside MP4, MKV or WebM rather than used as a standalone file.
A newer high-efficiency video codec used increasingly for web video, streaming and high-resolution media. Playback depends on AV1 decoder support and hardware capability.
Common use: Commonly found inside MP4, MOV, MKV, M2TS and camera files.
Widely used for 4K, HDR, newer phones and cameras. A file can be an MP4 or MOV while still requiring HEVC decoding support.
Common use: Often carries H.264, HEVC or AV1 video with AAC, AC3, DTS, FLAC, Opus or subtitle tracks.
MKV is a container, not a codec. If an MKV file does not play, the missing component is often the codec used by one of the streams inside it.
Common use: Most commonly H.264, HEVC or AV1 video with AAC audio.
MP4 is one of the most common modern containers. H.264/AAC combinations are widely supported; HEVC or AV1 inside an MP4 may need additional decoding support.
Common use: Typically VP8, VP9 or AV1 video with Vorbis or Opus audio.
Designed for open web media. Modern browsers handle WebM well, but desktop-player support still depends on the installed playback components.
Common use: May contain H.264, HEVC, ProRes, MJPEG or other video with AAC or PCM audio.
Common with iPhone, cameras and editing software. The MOV extension alone does not identify the codec inside the file.
Common use: Often H.264/AVC, HEVC or MPEG-2 video with AC3, DTS, AAC or other audio.
Common with Blu-ray, AVCHD, broadcast recordings and camera footage. Stream contents determine which decoders are required.
Older formats remain important because large personal, educational and downloaded-media archives still use them. Some now have relatively little modern documentation, even though users continue to encounter the files.
Common contents: Often DivX, Xvid, MJPEG, DV or older MPEG-4 video with MP3, AC3 or PCM audio.
AVI remains common in older collections and capture workflows. Playback problems usually come from the codec inside the AVI rather than the AVI extension itself.
Common contents: Usually MPEG-1 or MPEG-2 video and associated MPEG or DVD-era audio.
Still common in archived media, older camcorder footage and DVD-era material.
Common contents: Normally MPEG-2 video with AC3, DTS, MPEG audio or PCM plus DVD navigation/subtitle data.
VOB files are part of the DVD-Video structure and can contain several streams rather than one simple video track.
Common contents: Typically Windows Media Video and Windows Media Audio codecs.
An established Windows format family that remains common in older business, education and archived media.
Common contents: Older Flash-era video codecs or H.264/AAC in later files.
No longer a mainstream web-delivery format, but large archives of downloaded FLV/F4V video remain in use.
Common contents: OGV commonly contains Theora video with Vorbis audio; OGM was also used with several other codecs.
A legacy open-media format that still appears in archives and older web content. Windows Media Player may need suitable DirectShow decoding support for these files.
Common contents: Commonly H.263, H.264 or MPEG-4 video with AMR or AAC audio.
Often encountered in older phone recordings and mobile-device archives.
Common contents: RealVideo with RealAudio-family streams.
Now uncommon, but still encountered in older downloaded video collections.
Audio files may be standalone or may appear as tracks inside video containers such as MKV, MP4, MOV, M2TS and AVI.
Lossless compression commonly used for music archiving and high-quality playback.
AAC is widely used in MP4 video, streaming and portable devices; M4A commonly wraps AAC or ALAC audio.
Efficient modern audio used heavily for web, communications and WebM/Ogg-based media.
Common in DVD, broadcast, MKV and home-theatre material.
Common in DVD, Blu-ray and surround-sound media.
Often contains Vorbis or Opus audio; Ogg can also carry other stream types.
Apple Lossless audio commonly stored in MP4/M4A containers.
Long-established and extremely widely supported compressed audio.
Usually uncompressed PCM audio, although WAV can contain other codecs too.
Less common formats still found in music collections and older archives.
Containers describe how media is packaged; codecs describe how the audio or video is encoded. The same extension can therefore require different playback components from one file to another.
This page is a practical guide rather than a guarantee that every codec profile, damaged file, DRM-protected stream or unusual container combination will play in every Windows application.
Use the Media File Inspector to identify the video and audio streams in a file without uploading it. For playback problems, see the codec and playback error guides.