Central decoding controller and controlling method thereof

A central decoding controller, in which a video stream is processed and transmitted via at least two parallel channels, the central decoding controller comprises:

• a first terminal for receiving a video key frame obtained by decoding an original video frame via a first channel, and a plurality of intra-description frames neighboring the video key frame;
• a second terminal for receiving a predictive video frame obtained by processing a prediction analysis and an error correction to the original video frame via a second channel parallel to the first channel, and a plurality of inter-description frames via the second channel, the inter-description frames neighboring the video key frame;
• a correlator, coupled to the first terminal and the second terminal, for calculating correlation between the n inter-description frames, correlation between the video key frame and the neighboring inter-description frames, and correlation between the video key frame and the neighboring intra-description frames;
• an estimating logic and controller, coupled to the correlator, for controlling the correlator and outputting a signal according to the correlation results;
• and
• a multiplexer, for receiving the video key frame from the first terminal and the predictive video frame from the second terminal, the multiplexer coupled to the estimating logic and controller, in which the estimating logic and controller controls the multiplexer to select the video key frame or the predictive video frame as an output frame
• wherein when the estimating logic and controller determines that a condition (Δ−12+Δ+12)<(Δ−2+Δ+2) is satisfied, where (Δ−12+Δ+12) is the sum of the differences between the video key frame and the neighboring inter-description frames, and (Δ−2+Δ+2) is the sum of the differences between the video key frame and the neighboring intra-description frames, the estimating logic and controller controls the multiplexer to select the video key frame as the output frame.