Design And Implementation Of Embedded Multimedia Player

With the rapid development of information technology, in particular the popularity of the Internet, the acceleration of 3C (computer, communications , consumer electronics) t o be one technology, computer technology has begun to enter a technology known as the post-PC era, a variety of new embedded equipment has become a mainstream product of the times. In recent years, landing in China and with vigorous development, Linux also has been widely used in various types of computing applications. With superior performance and outstanding natural features in the high-end servers , Linux will surprise us again in the low-end embedded systems , and based on the application of embedded Linux operating system will take us with life-shaking changes in our study and work of the future. With Linux system the widely use in a variety of embedded devices , the requirements of multimedia applications on Linux system have become increasingly prominent. Therefore to develop an embedded multimedia player based on Linux system, supporting a variety of file formats, becomes an important research direction.Mplayer is the most powerful movie player on Linux. It is the fastest player under linux, supporting the most varieties of media player format, which can play almost all media files on windows. Running very stable on the X86 PC machine , it can also be ported to the embedded non-X86 CPU system. In this article , it is to develop a player, which takes Mplayer as a reference model, based on the UP-NETARM2410-S embedded test platform and RedHat 9.0 LINUX operating system , supporting common file formats (including RM streaming media format) the.Above all, this article introduces the technology about embedded multi-media player ~ the definition and advantages of embedded Linux; audio and video compression standards; the characteristics of streaming media and mainstream streaming media technology. Then it describes the hardware platform of the embedded media player—the resources which UP-NETARM2410-S embedded experimental platform has; the sub-module functions of ARM2410 experimental platform (the core board, audio circuits , display devices , the main interface).This article also gives the software system architecture of the embedded multimedia player. Including the establishment of development environment (Linux operating system installed; configure minicom , NFS, etc.) , to establish guide procedures (mainly to Select and program Bootloader), the transplantation of Linux operating system, the establishme nt of the root file system (create a root file directory system, create a variety of the necessary system files directory , create a device file , the establishment of startup-related configuration files , compile and install the library files , install system software and applications).And then it analyzes in detail the design of the player, gives the entire process flow of the player, according to the idea of decoding audio and video separately, it draws the audio decoding process and video decoding process(for MPEG). A detailed audio and video synchronization is given (based on timestamp). It also tells how to support RM media formats. It talks about if Mplayer can support other media formats. In support of this theory, the method how Mplayer can support RM media format and the specific operation are given. This is a difficult point of this article.In the part of realizing embedded multimedia player , it is needed to cross-compile libmad , which is to support the mp3 decoder, libmad and MPlayer is articulated through the designation of the generation of the same directory with the reference directory to achieve. Then through Configure and make two steps, it can generate an executable file. And then mount the folder through the minicom and NFS file system. Enter the implementation of the corresponding directory and see the results. It is found that the speed is not fast enough when it plays mpeg4 video files format in full-screen. Analyze the reasons and give the optimization method to improve it. However, due to lack of hardware performance , as well as the lack of floating-point operations , it has not enough abilities to play mpeg4 video player file format, as a result, unable to play very smoothly. This is the focus of this article.At the last of this paper, the player performance and functionality are tested, and test data are given. The experimental results show that the player can play all common file formats, response correctly according to play control, support full-screen playback, meet the needs of the embedded device media.The player features are:(1) Supports all kinds of media formats: not only can play WAV, MP3, WMA, AAC and other audio formats , but also play MPEG, AVI, ASF and other video file formats , including streaming media file format RM (only the low version of the RV10 and RV20 ).(2) Supports other media formats. To add one or a series of new codec, it is needed to decode interface function to add a new structure and this structure are added to the list, so that new entrants can use the decoder.(3) Has a lot of functions: supporting full-screen playback, pause, stop, dragging functions.In conclusion, the player designed in the paper completely meets the pre-set targets, but there are areas for improvement, for example: to support more media formats , including supporting several streaming media formats; To support other non-audio and video file format (word, PDF, etc.) and it can be identified automatically. These are my future direction.