Patent ID: 6862319

Claim:
A moving-picture coder receiving a moving-picture signal as an input signal, comprising: a resolution-converting motion estimator comparing said moving-picture signal with a reference picture signal having reduced resolution, selecting one of predictive coding and intra-frame coding, and generating full-resolution motion vectors if said predictive coding is selected; a resolution-converting motion compensator coupled to said resolution-converting motion estimator, applying said full-resolution motion vectors to said reference picture signal and performing resolution conversion, thereby generating a first picture signal having full resolution and a second picture signal having said reduced resolution, when said predictive coding is selected; a subtractor coupled to said resolution-converting motion compensator, generating a third picture signal by subtracting said first picture signal from said input signal when said predictive coding is selected, said third picture signal being identical to said input signal when said intra-frame coding is selected; a DCT processor coupled to said subtractor, carrying out a discrete cosine transform on said third picture signal, thereby obtaining a transformed picture signal; a resolution-converting IDCT processor coupled to said DCT processor, carrying out an inverse discrete cosine transform and resolution conversion on said transformed picture signal, thereby obtaining a fourth picture signal having said reduced resolution; an adder coupled to said resolution-converting IDCT processor, adding said second picture signal and said fourth picture signal, thereby obtaining said reference picture signal; and a memory coupled to said adder, storing said reference picture signal.