Flash Video is a container file format used to deliver video over the Internet using Adobe Flash Player versions 6–10. Flash Video content may also be embedded within SWF files. There are two different video file formats known as Flash Video: FLV and F4V. The audio and video data within FLV files are encoded in the same way as they are within SWF files. The latter F4V file format is based on the ISO base media file format and is supported starting with Flash Player 9 update 3. Both formats are supported in Adobe Flash Player and currently developed by Adobe Systems. FLV was originally developed by Macromedia.

The Adobe Flash Player is a multimedia and application player originally developed by Macromedia and acquired by Adobe Systems. It plays SWF files, which can be created by the Adobe Flash authoring tool, Adobe Flex, or a number of other Adobe Systems and third party tools. It has support for a scripting language called ActionScript, which can be used to display Flash Video from an SWF file. Because the Flash Player runs as a browser plug-in, it is possible to embed Flash Video in web pages and view the video within a web browser.

However you must want to convert video to flv on Mac for playing Flash FLV files

Luckily, a friend of mine recommended me a FLV to MPG Converter Mac which he tried very great. I download the free trial and found it's very easy to use, and can help you convert FLV videos to .mpg (MPEG-1, MPEG-2) on Mac for Mac OS. Then I bought it without any hesitating. If you have the same problem with me, maybe you can try it. Learn the details about how to convert FLV to MPG on Mac! Hope to help you.