OGV to MKV Converter
FileFlip converts OGV to MKV entirely inside your browser, using WebCodecs and FFmpeg compiled to WebAssembly. The file is never uploaded to a server: it is read off your disk, converted on your own machine, and saved back by the browser. That means no file-size limit, no queue and no account.
How do I convert an OGV file to MKV?#
- Drop your OGV file onto the converter at the top of this page, or click it to pick one from your computer. You can add as many as you like.
- Leave the target set to MKV and the conversion starts on its own. FileFlip usually downloads nothing, falling back to 30.8 MB of WebAssembly if your browser cannot encode these codecs itself, then runs WebCodecs and FFmpeg on your own machine.
- Save the MKV file. Your browser writes it straight to your downloads folder, because there was never a server holding it.
Does converting OGV to MKV lose quality?#
Sometimes. When the codecs inside the OGV file are ones the MKV container can hold, the streams are copied straight across and nothing at all is lost. When they are not, the file has to be decoded and encoded again, and that step does cost a little quality.
Is it safe to convert OGV files online?#
Yes, because nothing is uploaded. FileFlip converts OGV files inside the browser tab you already have open, using WebAssembly builds of the same engines a desktop converter would install. Your file is read from your own disk into the page's memory, and no request carrying it is ever made.
You do not have to take that on trust. Open your browser's network panel, run a conversion, and you will see the engine come down and your file go nowhere. There is no upload, no server-side copy, no retention window, and no account tied to what you converted.
How FileFlip works lists every engine, its version and its download size, and shows how to check for yourself that nothing leaves your machine.
What OGV to MKV actually does to the file#
Converting OGV to MKV runs on WebCodecs and FFmpeg, usually downloads nothing, falling back to 30.8 MB of WebAssembly if your browser cannot encode these codecs itself, copies the streams through when the codecs fit and re-encodes when they do not.
| Engine | WebCodecs and FFmpeg |
|---|---|
| Conversion path | One step: OGV → MKV |
| Downloaded to your browser | Nothing in most browsers, or 30.8 MB if yours cannot encode these codecs itself |
| Quality | Lossless when the codecs fit, lossy when they do not |
| You get back | One file |
| Where it runs | In a background worker, so the page stays responsive |
What survives the conversion
| What is in the file | This conversion | Why |
|---|---|---|
| Encoded streams | Sometimes | Survives for some files and not others. |
Worth knowing before you start:
- the FFmpeg fallback is an LGPL build, so a re-encode produces MPEG-4 Part 2, VP8, VP9, or Theora rather than H.264 or H.265
- whether the browser can do this without FFmpeg depends on the codecs it exposes through WebCodecs
- the encoded streams are copied when the file's codecs fit the target container, and re-encoded when they do not
What is an OGV file?#
An OGV file holds video wrapped in Xiph.Org's Ogg container, almost always Theora-encoded video paired with Vorbis audio, built as a patent-free alternative at a time when H.264 carried real licensing costs.
Reach for OGV only when a target system specifically requires Ogg Theora, such as older Wikimedia tooling or a free-software media pipeline that has not moved on.
Convert OGV to MP4 or WebM for anything that needs to play in a current browser, since native Theora support has been dropped from both Chrome and Firefox.
What is an MKV file?#
An MKV file is a Matroska container built on the EBML binary format, and it can hold any number of video, audio, subtitle and attachment tracks, encoded with essentially any codec, in a single file.
Use MKV when a video needs multiple audio tracks, several subtitle languages, or a codec MP4 doesn't accommodate, and it's staying on software you control, like a media server or a desktop player.
Convert MKV to MP4 when a file needs to play on a device that never added MKV support, since that's usually a hardware or software gap rather than anything wrong with the codec inside.
OGV to MKV questions people ask#
What plays OGV files today?
VLC opens OGV files on Windows, macOS and Linux without any extra codecs, since it bundles its own Theora and Vorbis decoders. mpv and GNOME Videos on Linux handle it the same way. Neither Chrome nor current Firefox will play an OGV file dropped straight into the browser any more.
Does Wikipedia still use OGV?
Wikimedia sites used OGV as their standard video format for years because Theora and Vorbis carry no patent licensing, matching the free-content mission of the projects. Wikimedia has since moved to VP9 for new video, though a large amount of older OGV footage remains on Wikimedia Commons.
Is Ogg the same thing as OGV?
Ogg is the container format, and OGV is the specific case of an Ogg file holding a Theora video stream, the same way MP4 is a container and M4V is one particular use of it. A plain .ogg extension more often holds Vorbis audio with no video track at all.
Why won't my TV or game console play an MKV file?
MKV is just a container, so the refusal is almost always about the container itself rather than the codec inside it. A lot of hardware players, smart TVs, the PS5, some streaming boxes, never implemented support for parsing Matroska, even though they can decode the exact same H.264 or H.265 video when it's wrapped in an MP4.