Buffer controlled picture signal encoding and decoding system

A picture signal encoding and decoding apparatus having an encoding section for converting a series of picture elements whose number is predetermined (one picture frame or one line etc.) of a digitized picture signal series to a variable-length code-word series for transmission;

• and a decoding section for receiving a transmitted encoded signal and converting the signal to a fixed-length signal and after that decoding the signal to a digital picture signal series;
• said picture signal encoding and decoding apparatus comprising:
• a transmitting buffer for performing speed conversion by storing data temporarily in order to transmit a sequence of said variable-length code-word series at a constant transmission rate;
• a reference timing pulse generator being able to create reference timing pulses having an adjustable fixed period;
• and
• a timing comparing and adjusting section for sensing the timing of head timing pulses positioned at the head of each of said variable-length coded-word series corresponding to said series of picture elements whose number is predefined which are read from said transmitting buffer and for determining the time difference between said head timing pulses and said reference timing pulses, and if said reference timing pulse is found to occur later than said head timing pulse, the magnitude of the time difference between said reference timing pulse and said head timing pulse is determined, and if the magnitude of said time difference is larger than a predetermined threshold value, the reading from said transmitting buffer is stopped and, after the insertion of dummy data, is then resumed to compensate for said time difference, and if said reference timing pulse is found to occur earlier than said head timing pulse, said reference pulse generator is reset to effect time adjustment to correct for the time difference between said reference timing pulse and head timing pulse whereby encoded-data series to be transmitted can be adjusted time-serially based on the reference timing given by said reference timing generator.