| As a new generation video coding standard, H.264 features strong applicability, high compression rate and good image quality. Under the same reconstructed image quality, it's more suitable for video transimission under severe channel conditions, compared to previous video standards. However, these advantages bring about significant increase of the algorithm complexity, thus how to achieve high-quality and efficient H.264 video coding in embedded video systems is studied extensively.Dual cores architecture based DaVinci processor released by Texas Instrument (TI) is the ideal implementation platform for the new generation multimedia communication terminals. On DaVinci platform, digital media processing algorithms need to meet the xDM algorithm standard proposed by TI, which will be called by applications through Codec Engine framework.To realize the DaVinci platform based video system, the transplantation and optimization methods of H.264 video coding algorithm is studied first, then xDM standard-compliant X264 algorithm codec is created as needed by Codec Engine framework, which serves as a bridge when the algorithms are called by the application. Also, a tool system is designed and implemented to integrate digital media processing algorithms to Codec Server and applications automatically, whose functionalities include quick integration, verification and modification of xDM standard-compliant algorithms, without the inconvenience of Codec Server integration and application deployment.The key technologies of H.264 video coding are investigated and the opensource code X264 is transplanted to DaVinci platform, considering platform-specific hardware resources. Then the code is optimized by different tuning methods, such as compiler options optimization, C code optimization, assembly optimization and memory allocation optimization. The coding frame rate is less than 1 fps before optimization compared to about 18 fps after optimization for CIF videos. |
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