Convert flv to mkv
Converted on your device. Files never leave this tab. Output tops out around 2 GB.
Nothing is uploaded
The converter runs inside this page. Cut your network after it loads and it still works.
No account, no daily limit
No sign-up, no daily limit, no watermark, no queue behind other people's files. Batch as many FLV files as you like.
Real MKV output
Encoded by ffmpeg, the same library the command-line tools use — not a renamed extension.
About FLV
Flash Video
Adobe's container for Flash Player, which carried most web video in the late 2000s, usually with Sorenson Spark, VP6 or H.264 video. Flash Player was discontinued at the end of 2020. Convert FLV to MP4 to play saved Flash-era video now that Flash is gone.
About MKV
Matroska Video
An open container first released in 2002 that can hold almost any video and audio codec, plus several audio tracks, subtitle tracks and chapters in one file. Use it to keep multiple languages and subtitles together; convert to MP4 for devices that do not read MKV.