FLV files: Flash video, and how to rescue what is in them
Why FLV files stopped playing in 2020, what is usually inside them, and whether to keep the picture. Convert FLV in your browser, no upload.
At a glance
- Type
- Video
- Container format
- Yes
- Extensions
- .flv
- MIME type
- video/x-flv
- Common codecs
- h264, aac, mp3
- Also known as
- Flash Video
FLV was the container of Flash video, which for roughly a decade meant the container of web video. Browsers removed Flash entirely at the end of 2020, and with it went the only runtime most people had that could open these files. The files themselves are intact — nothing rotted — they simply have nothing left to play them.
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What survives in FLV archives is overwhelmingly instructional: recorded lectures, training courses, tutorials, webinars, conference sessions. The video is usually Sorenson Spark or VP6 at low bitrates and small frame sizes, because it was encoded for the connection speeds of the time. The audio is usually MP3 or AAC.
That shapes the advice. Converting to MP4 re-encodes every frame to H.264 and works, but the result will look exactly as soft as the original — a small, low-bitrate picture cannot be improved by re-encoding it. For most FLV content the audio is the substance, and extracting it is faster, produces a far smaller file, and skips the picture quality loss entirely.
Convert FLV to other formats
FAQ
Why can nothing open my FLV files?
Because they were made for Flash, which browsers removed at the end of 2020. The files are fine; the runtime they depended on no longer exists anywhere.
Will the MP4 look better?
No. Flash-era video was encoded at low bitrates and small frame sizes, and re-encoding cannot add detail that was never recorded.
Should I convert the video or extract the audio?
For a lecture, tutorial or webinar — which is most FLV content — extract the audio. It is faster, much smaller, and skips the picture quality loss.
How long does converting take?
A noticeable fraction of the clip's length, since every frame is re-encoded. FLV's typically small frame sizes make it quicker than a modern video of the same duration.
Can I convert a folder of them at once?
Twenty files per batch, converted one after another on your own machine. No uploads and no per-file limits.
Is the audio identical to the original?
No. It is decoded and re-encoded rather than copied, which is a second lossy pass. For speech at ordinary bitrates the difference is not audible.