Patent ID: 7580612
Filing Date: 2009-08-25
Classification: H04H,H04N

Abstract:
1. A digital broadcast receiving apparatus having a video display unit for displaying an image by receiving a multiplexed broadcast signal including a high-quality first video code and a low-quality second video code generated from the same video content and each including a sync signal, comprising: a demultiplex processing unit for demultiplexing the data multiplexed on the broadcast signal; a first decoder for decoding the high-quality first video code and the sync signal thereof; a second decoder for decoding the low-quality second video code and the sync signal thereof; a first buffer for holding a high-quality video signal decoded by the first decoder; a second buffer for holding a low-quality video signal decoded by the second decoder; an enlargement processing unit for recovering and enlarging the low-quality video signal from the second buffer; a switching determination unit for monitoring the receiving condition of the high-quality video signal and determining whether the receiving condition is good condition or not; and a sync adjustment unit for recovering the high-quality video signal from the first buffer in the case where the determination result of the switching determination unit is good condition, recovering the enlarged low-quality video signal from the enlargement processing unit in the case where the determination result is negative and outputting the recovered video signal to the video display unit in accordance with the delayed one of the sync signals, wherein in switching between the high-quality video display and the low-quality video display, the sync adjustment unit switches the high-quality image to the low-quality image or the low-quality image to the high-quality image gradually during a predetermined time, wherein the first buffer and the second buffer hold the video frame image for at least the predetermined time, wherein the sync adjustment synthesizes the video frame image held in the first buffer and the video frame image held in the second buffer at a predetermined synthesis ratio, and wherein after the time point when the switching determination unit issues a switch instruction before the lapse of the predetermined time, the synthesis ratio is gradually changed for each frame display from the synthesis ratio as of the time point when the switching instruction is issued to the final synthesis ratio.