As the de facto standard for dynamic media on the web, Adobe Flash supports a number of media formats. These include two core open container formats for delivering synchronized audio and video streams: F4V and FLV. F4V builds on the open standard ISO/IEC 14496-12:2008 (MPEG-4 Part 12) ISO base media file format and supports H.264/AAC–based content. It has a flexible structure and defines specific supported codecs and extensions, facilitating simplified interoperability across tools, services, and clients. FLV supports codecs such as Sorensen Spark and On2 VP6, and encodes synchronized audio and video streams in the same way as they are encoded in SWF files.

FLV and F4V File Format Specification (Version 10.1)

The open FLV and F4V file format specification specification documents file format information for storing media content used to deliver streaming audio and video for playback in Adobe Flash Player and Adobe AIR. These video file formats are open, allowing other products and technologies to implement these specifications.

Download the video file format specification (PDF, 594 KB)file

Adobe seriously considers community feedback to improve the video file format specification. Please share any unclear or potentially erroneous information within the specification to Adobe at to fileformat@adobe.com. All e-mail submissions shall be subject to the Terms of Use.