Research On The Key Technologies Of Multimedia Playing Based On Symbian Platform

At present, mobile communications business has made great progress in China, with thepopularity of the third generation mobile communication networks and the increasing processingcapabilities of mobile intelligent terminal, applications such as video-on-demand based onstreaming media technology has become the community focus, developing fast. However, thehighly complexity of H.264decoding and the process limitations of intelligent terminal arerestricting the further development of streaming media services.This paper focuses on the caching mechanism of mobile terminal, the decoding algorithm ofH.264and the application optimization of mobile, combined with the characteristics of Symbianplatform, the corresponding solutions are put forward. The main work of this paper has listed asfollows:Firstly, research the traditional caching mechanism in-depth, and then analysis the advantagesand disadvantages of water level cache and ring buffer mechanism, and at last put forward thedynamic loop caching mechanism which has great improved. The mechanism can dynamicallydetermine the size of the cache space, improve utilization of the cache space and increase the rateof "back" operation.Secondly, study on the core module of H.264decoding. For the loop filter, improved methodsare put forward based on sequence of loop filter and the calculation of boundary strength; takeadvantage of the speed superiority of register and correlation of pixels to reduce redundancy andimprove the decoding speed. For interpolation, improved methods are proposed from calculatemethods and judgment of cross-border to reduce the running time. For entropy decoding, acombination of table lookup and binary tree method is come up with to reduce the decoding time.In addition, optimize the application that based on the Symbian platform form object-orientedoptimization, memory optimization, programming style optimization, operator optimization, anddisplay optimization. Analysing the conclusions with a Mobot tool, the result shows that runningspeed and display of optimized program are improved.Finally, the transplant process of H.264decoder library is described in details, using the OpenC technology that provided by Symbian OS and the open source project of FFmpeg, this papermakes a detail describe in the key steps of transplant process, and finally gives the results oftransplantation.