Video signal encoding and recording apparatus with variable transmission rate
View Patent ↗In a video signal encoding and recording apparatus, a video signal is quantized into a quantization-resultant signal in response to a variable quantization scale. The quantization-resultant signal is recorded on a recording medium. The quantization scale is controlled in response to an encoding rate. The quantization scale is limited to within a range determined by a limit quantization scale. A remaining record capacity of the recording medium is measured. A remaining record time is measured. The encoding rate and the limit quantization scale are updated in response to the measured remaining record capacity and the measured remaining record time.
1. A video signal encoding and recording apparatus comprising:
first means for quantizing a video signal into a quantization-resultant signal in response to a variable quantization step;
second means for recording the quantization-resultant signal generated by the first means on a recording medium;
third means for calculating a remaining record capacity of the recording medium;
fourth means for determining a capacity of a virtual buffer in response to the remaining record capacity calculated by the third means;
fifth means for calculating a degree of occupancy of the virtual buffer having the capacity determined by the fourth means; and
sixth means for controlling the quantization step used by the first means in response to the virtual-buffer occupancy degree calculated by the fifth means;
wherein the fifth means comprises means for determining a target mean transmission rate in response to the remaining record capacity calculated by the third means, means for detecting a transmission rate of the quantization-resultant signal, and means for calculating the virtual-buffer occupancy degree in response to the target mean transmission rate, the detected transmission rate, and the virtual-buffer capacity determined by the fourth means.
2. A method of encoding and recording a video signal, comprising the steps of:
quantizing a video signal into a quantization-resultant signal in response to a variable quantization step;
recording the quantization-resultant signal on a recording medium;
calculating a remaining record capacity of the recording medium;
determining a capacity of a virtual buffer in response to the calculated remaining record capacity;
calculating a degree of occupancy of the virtual buffer having the determined capacity; and
controlling the quantization step in response to the calculated virtual-buffer occupancy degree;
wherein the virtual-buffer occupancy degree calculating step comprises determining a target mean transmission rate in response to the calculated remaining record capacity, detecting a transmission rate of the quantization-resultant signal, and calculating the virtual-buffer occupancy degree in response to the target mean transmission rate, the detected transmission rate, and the determined virtual-buffer capacity.