Design Of Digital Multimedia Player System Based On DM6446

With the rapid development of digital technology, the era of digital video has arrived. Digital technology is making the video experience, transmission and exchange of people profoundly changed. The play of digital video requires a dedicated digital multimedia projection system. The traditional ASIC (specific integrated circuit) is an integrated circuit which is designed for the specific needs and often limits the use and function of the device. Facing the changes of the standards and applications of multimedia, the ASIC is difficult to meet the requirements of multifunction, low cost, and high flexibility.However, the emergence and development of DaVinci technology has changed all the above fundamentally. The digital video development platform with TMS320DM6446 as the core provides us with a good hardware solution; the software framework based on DaVinci technology provides an efficient approach for the video development. Above all, we introduce the structural features of TMS320DM6446, which is a highly integrated digital video processing chip. And then, considering the needs of practical application, with the core of TMS320DM6446, drawing on the DaVinci development kit (EL-DM6446) of the technology company of Beijing Da Sheng, we give the overall design of hardware system of digital media player. Meanwhile, we elaborate the functions of each module of hardware system in details, including:DDR2 module,Flash module,ATA controller module,video processing subsystem,Ethernet media access controller module and UART controller module. The ARM core of DM6446 runs the Linux operating system, which provides a good system schedule for application development;DSP core has a high processing speed, which enhanced the capabilities of audio and video decoding greatly. Therefore, the digital video development platform based on DM6446 is the preferred choice for digital multimedia video player system.We mainly study the development of software part of digital multimedia player system, in order to solve the urgent needs of digital cinema projection terminal equipment. First, on the hardware development platform of TMS320DM6446, an embedded Linux operating system has been built; the development environment of DaVinci software is also built, using the support of DaVinci high-level Linux, standardized APIs and product-oriented underlying drivers, through the implementation framework of Codec Engine, the development of digital multimedia decoder has been completed, which realizes to decode the audio and video files in different formats (MPEG-2, MPEG-4, H.264, AAC, MP3, G.711), through the simulation output interface of the system, the decoding image can display on the OSD, and the decoding resolution can been up to 720 x 576. Meanwhile, in order to ensure the security of digital video, avoid video data to be illegal theft or malicious tampering, this paper transplants the advanced symmetric encryption algorithm AES-128 on the DaVinci hardware development platform. And taking MPEG-2 as an example, by analyzing the video stream and frame coding structure of MPEG-2, different video encryption schemes of MPEG-2 are studied under different security levels. And, from two aspects of structure of AES algorithm and characteristics of dual-core processor-TMS320DM6446, using four different optimization strategies to optimize the AES-128 encryption algorithm, making it to meet the requirement of real time. Finally, while decoding, we use the private key to decrypt the encrypted video, which ensures the video to be played non-destructive and real-time.