Convert F4V to FLV — Free Online Converter

F4V and FLV are both Adobe Flash video formats, but they differ fundamentally in their container structure and codec support. FLV (Flash Video) is the original Flash container from 2002, using Sorenson Spark or VP6 video with MP3 or Nellymoser audio. F4V replaced FLV in 2007, adopting the ISO base media file format with H.264/AAC — essentially an MP4 variant with Flash metadata. Converting F4V to FLV moves content from the newer Flash container back to the legacy format.

The main reason to convert F4V to FLV is compatibility with older Flash-based systems that specifically require the FLV container. Some legacy media servers (Red5, Wowza with old configurations), Flash-based video players still running in isolated environments, and archival systems catalog content by the .flv extension. While both formats are technically obsolete, FLV has broader recognition in legacy tooling and some streaming workflows.