Abstract: A picture in picture video signal processing circuit does not need an extra synchronization generator because sub picture video signals are synchronized with the main picture video signals by storing decoded sub picture video signals in a memory then reading the decoded sub picture video signals out in response to synchronization signals of the main picture video signal. Further, the memory can be of a lower capacity owing to the fact that the synchronization signals of the sub picture video signal are not stored.

Abstract: A scanning line converting apparatus for converting between NTSC and PAL formats includes a plurality of line memories, an arithmetic circuit and a picture memory. Switches in the lines connecting these elements permits the order of connection to be shifted between first and second states. When converting from the PAL system to the NTSC system, 5 lines are formed by varying the mutual signal ration of 2 lines for every 6 lines, while, when converting from the NTSC system to the PAL system, 6 lines are formed by varying the ratio of 2 lines for every 5 lines, thereby making it possible to convert the lines of one field of different broadcasting methods when actually scanning the picture tube. The ratios used in computations performed by the arithmetic circuit are related to horizontal synchronizing signals and to vertical blanking signals, while they are also related to constants which are furnished by a percent block. A method for converting between different broadcasting formats is also described.

Abstract: An automatic converting device of a television broadcasting mode compatibly converts the standard television broadcasting signals such as NTSC, PAL, SECAM, M-PAL and N-PAL. A video memory able to store two fields is employed for standard television signal conversion without using a large number of the field memories.