MP4 is a player that can play MPEG-4 files equipment, it can be called PVP (Personal Video Player, personal video player) can be called PMP (Portable Media Player, a portable media player). MP4 player now there is no specific definition of the function, although many companies are defined as multi-media audio and video players, but it apart from listening to the basic function of watching movies, also supported music player, browse picture, and even some products can also access . However, in order to emphasize the characteristics of portable, we are here to discuss the MP4 player is going to be portable, video as the standard, they can be adopted by 1394 or USB port file transfer, it is easy to download video equipment for broadcast , and should bring their own LCD screen to meet the needs of video playback at any time.

        MPEG-4 technology makes the emergence of high-quality video can be compressed more small, which many users have been through different channels have been confirmed in the film, and the introduction of a long time, many companies support, you can easily obtain this the film resources. But the real MP4 player to the benefit of the encoder is derived from MPEG-4 technology - Divx, Xvid.

        But in the enjoyment of high-quality video encoding technology, MP4 player has encountered some difficulties: As the MPEG-4 coding technology complexity and the large number to Divx, Xvid for example, Divx technology encoded AVI video files can be called MPEG-4 , and to Xvid encoded AVI video files can be called MPEG-4. Two completely incompatible encoding formats generated by the MPEG-4 files using the same extension, how fast player, perfectly compatible encoding different document is a matter of concern.

         MP4 players require a fairly powerful decoder chip to complete the video decoding process document, if you use a computer is a long time remember that users should be able to come out in the beginning of Divx encoder, the encoder developers recommend using the frequency of 400 MHz or computer to complete codec (encoder Xvid there late, but with the volume of data and decode Divx basically the same). Although dedicated DSP chip and the CPU chip to apply a different focus, but they, MP4 players in the chip does not require calculations simple. Not only that, MP4 players are portable devices, we will have to chip integration features (such as support LCD display, CF, SD memory card, or hard disk interface controller, etc.) and lower energy consumption, it is precisely because of these harsh only the requirements of the MP4 player long overdue.

          Fortunately, now there are many MP4 players, high-performance DSP chips can choose not only introduced the high-performance Intel Xscale processor, but as TITMS320DSC21/DSC25/DM270/DM310, such as Sigma Designs EM8510 mature ASIC also appeared in succession, they can support LCD display, USB 2.0/IEEE 139, hard drive interface control functions can also support MPEG-1, MPEG-2, DivX files decoder, and can be maintained in 720 × 480 pixel resolution 30 / s codec speed , in function and performance for portable players paving the way to development.