Fristly ,thanks for all reply my topic last days pasted. i found some intertesting stuffs yesterday, as fellow: Apple iPod is famous for its high extension, compared with MP3 and MP4 made by Japan or Korea. Apple iPod can be called mini computer. The following transformation is a little exaggerated: Apple iPod nano is transformed into a TV set. Please Register or Log in to view images The prototype of the TV set: iPod Nano Please Register or Log in to view images The key point is the Lens in front of the screen. Please Register or Log in to view images The task to transform the iPod into TV set is completed. Apple TV is the device to store files on PC (Apple computers or windows coomputers) with the technical of wire or wireless net receiving. Many users use Apple TV, LCD TV and the Stereo device to build the home Theatre. But how does Apple TV realize the stereo? Apple company announces recently the technical support files and let all the friends that need it make a reference about how to realize the surrounded stereo. Below is the detailed information: According to the file, if you want to play the movie with AC-3 surround stereo on Apple TV, the movie files need exist in two audio tracks: the Advanced Audio Coding (AAC) stereo and “AC-3 surround” at the same time. Moreover, they must have the same sample rate (generally 48Khz). In addition, considering the compatibility, it is suggested to use the following specifications for movie audio tracks: ? AAC audio track must be in the front and open to use. ? AC-3 audio track must be behind AAC and preset it as “close” ? AC-3 audio track must use the appropriate MPEG-4/ISO standard. You can use a conversion tool if you do not have the specifications above: it is recommended to use Pavtube video converter. The audio format is chosen to be AAC codec. See the picture: Please Register or Log in to view images Notice: you can use other converters,any tools as you like, my pc install this tools ,so let me take it for example. Surround audio track will be able to use HDMI of Apple TV or Fiber terminal for output files. Come to the settings: settings>audio>Dolby Digital Out. Check it as “on” and enjoy the surround stereo effects that Apple TV has brought.