Detect whether an flv file contains video, audio or both

Is there a开发者_JS百科 way to detect whether an FLV file contains video, audio or both? The flv file is streamed to a flash client, that needs to show a certain view depending on the data in wrapped in the flv file.

According to the FLV specs, this is indicated in the 5th byte of the file.
(Bit 2 is set if there is audio and bit 0 is set if there is video.)