This paper analyzes the down sample effect on harmonics using Discrete Fourier Transform(DFT),analyzes the frequency division character of WPT,Simulations validate the results obtained.

To improve the video decoding ability on the multimedia processing capability limited terminals, an effective algorithm is proposed to implement the DCT-domain downsampling video decoding.

264/ AVC 4-tap integer Transform (IT) coefficients while downsampling at the same time.

After down-sampling the training symbol into several L-point sub-symbols and demodulating part of them by means of a new FFT algorithm considering the factor of the fractional frequency offset,the scheme estimates the integer frequency offset by finding the maximum magnitude of the combined resulting frequency domain signals.

In order to solve the problem that the traditional down-sampling methods can not adapt to the different application requirements,an inherent identity of implementation technique between down-sampling and interpolation of image scale transform is proposed,and then many advanced interpolation methods can be used in down-sampling.