How to convert FLV to WebM
- Click Choose files or drop your FLV video into the box above.
- Keep the default quality, or choose a target size, resolution or frame rate.
- Click Convert and download the WebM when it is ready.
FLV vs WebM
| FLV | WebM | |
|---|---|---|
| Usual codecs | Sorenson Spark, VP6 or H.264 video with MP3 or AAC audio | VP8, VP9 or AV1 video with Opus or Vorbis audio |
| Plays on | Only VLC and similar players — Adobe Flash Player was discontinued in 2020 | Chrome, Firefox, Edge and Android; partial support on iPhone and Mac; not accepted by many editors |
| Best for | Nothing today: convert old Flash videos to MP4 | Video embedded in websites and screen recordings |
| Introduced | early 2000s by Macromedia / Adobe | 2010 by Google |
About FLV and WebM
What is FLV?
FLV was the format behind early YouTube and most web video of the 2000s, played through Adobe Flash Player. Flash was shut down at the end of 2020, so FLV files no longer play in browsers. Converting them to MP4 keeps old videos watchable everywhere.
- Small files
- Obsolete: Flash Player is gone
- Plays only in a few desktop players
What is WebM?
WebM is an open, royalty-free video format designed for the web. Screen recorders and browsers often save clips as WebM. It is efficient, but many video editors, iPhones, smart TVs and upload forms do not handle it well, so WebM files are frequently converted to MP4.
- Royalty-free and efficient
- Plays in Chrome, Firefox and Edge
- Weak support in editors, TVs and some Apple apps
Why GlideConvert?
- Private by design. Your files are converted on your own device by your browser — they are never uploaded to a server. That keeps them private, avoids upload waits and means there is no queue.
- Fast. Images convert in a fraction of a second; video uses your device’s hardware encoder and is often simply repackaged without re-encoding.
- Free. No sign-up, no watermark. 10 images, 5 audio files or one video at a time — Pro lifts the limits and removes ads.
Frequently asked questions
Will converting FLV to WebM lose quality?
Often not at all. If the FLV file already contains video and audio that WebM supports (H.264 video and AAC audio are the most common), they are copied as-is: no quality loss, and even a large file converts in seconds. Otherwise the video is re-encoded at high quality — choose a quality level or a target file size in the options.
How long does converting FLV to WebM take?
Usually much less than the length of the video: modern browsers encode video with your device’s hardware. FLV needs a universal decoder (FFmpeg compiled to WebAssembly, a one-time ~32 MB download) which is slower — expect roughly real-time speed for HD video.
Is FLV still worth keeping?
FLV is obsolete — Flash Player was discontinued in 2020. Converting to MP4 keeps your videos watchable on any device for years to come.
Which codecs does the WebM use?
VP9 video with Opus audio when your browser can encode them (falling back to VP8), the standard WebM combination supported by Chrome, Firefox, Edge and Android.
Is there a file size limit?
On the free plan each video or audio file can be up to 500 MB and each image up to 100 MB. With Pro the limit is 4 GB per file. Because everything happens on your device, the practical limit for very large files is your device’s memory.
Are my files uploaded to a server?
No. GlideConvert runs entirely in your browser: images are processed with the browser’s built-in codecs and WebAssembly, video and audio with hardware-accelerated WebCodecs (or a WebAssembly build of FFmpeg for older formats). Nothing is sent anywhere — you can even disconnect from the internet once the page has loaded.
Does it work on iPhone, Android, Mac and Windows?
Yes. It works in any up-to-date browser — Chrome, Edge, Safari, Firefox or Samsung Internet — on phones, tablets and computers, with nothing to install. Long or 4K videos convert faster on a computer than on a phone.