Image processing apparatus

An image processing apparatus comprising:

• a quantizing unit configured to quantize an input moving image signal using a set quantization scale;
• a coding unit configured to perform variable length coding on an output of the quantizing unit;
• an activity detecting unit configured to detect an activity of the input moving image signal;
• a quantization-scale determining unit configured to determine the quantization scale on the basis of the amount of variable length codes output from the coding unit;
• a changing unit configured to change, on the basis of the activity detected by the activity detecting unit, the quantization scale determined by the quantization-scale determining unit, and to set the changed quantization scale in the quantizing unit;
• a filling level detecting unit configured to detect, on the basis of the amount of variable length codes output from the coding unit, the filling level of a virtual buffer in a decoder which decodes the coded moving image signal;
• and
• a control unit configured to perform control, according to the filling level detected by the filling level detecting unit, as to whether the quantization scale determined by the quantization-scale determining unit is to be changed on the basis of the activity.

An image processing method comprising:

• quantizing an input moving image signal using a set quantization scale;
• performing variable length coding on the quantized moving image signal;
• detecting an activity of the input moving image signal;
• determining the quantization scale on the basis of the amount of variable length codes obtained from performing variable length coding on the quantized moving image signal;
• changing the determined quantization scale on the basis of the detected activity, and setting the changed quantization scale as the quantization scale;
• and
• detecting, on the basis of the amount of variable length codes, the filling level of a virtual buffer in a decoder which decodes the coded moving image signal, and controlling the changing of the determined quantization scale such that the degree of change in the quantization scale caused by use of the activity is reduced as the detected filling level decreases.

An image processing method comprising:

• quantizing an input moving image signal using a set quantization scale;
• performing variable length coding on the quantized moving image signal;
• detecting an activity of the input moving image signal;
• determining the quantization scale on the basis of the amount of variable length codes obtained from performing variable length coding on the quantized moving image signal;
• changing the determined quantization scale on the basis of the detected activity, and setting the changed quantization scale as the quantization scale;
• detecting, on the basis of the amount of variable length codes, the filling level of a virtual buffer in a decoder which decodes the coded moving image signal;
• and
• performing control, according to the detected filling level, as to whether the determined quantization scale is to be changed on the basis of the activity.

An image processing apparatus comprising:

• a quantizing unit configured to quantize an input moving image signal using a set quantization scale;
• a coding unit configured to perform variable length coding on an output of the quantizing unit;
• an activity detecting unit configured to detect an activity of the input moving image signal;
• a quantization-scale determining unit configured to determine the quantization scale on the basis of the amount of variable length codes output from the coding unit;
• a changing unit configured to change, on the basis of the activity detected by the activity detecting unit, a value determined by the quantization-scale determining unit, and to set the changed value, as the quantization scale, in the quantizing unit;
• and
• a filling level detecting unit configured to detect the data rate of moving image data output from the coding unit, and to control the changing unit such that the degree of change in the quantization scale caused by use of the activity is reduced as the detected data rate decreases.

A computer readable medium containing computer-executable instructions for coding images, the medium comprising:

• computer-executable instructions for quantizing an input moving image signal using a set quantization scale;
• computer-executable instructions for performing variable length coding on the quantized moving image signal;
• computer-executable instructions for detecting an activity of the input moving image signal;
• computer-executable instructions for determining the quantization scale on the basis of the amount of variable length codes obtained from performing variable length coding on the quantized moving image signal;
• computer-executable instructions for changing the determined quantization scale on the basis of the detected activity, and setting the changed quantization scale as the quantization scale;
• and
• computer-executable instructions for detecting, on the basis of the amount of variable length codes, the filling level of a virtual buffer in a decoder which decodes the coded moving image signal, and controlling the changing the determined quantization scale such that the degree of change in the quantization scale caused by use of the activity is reduced as the detected filling level decreases.

A computer readable medium containing computer-executable instructions for coding images, the medium comprising:

• computer-executable instructions for quantizing an input moving image signal using a set quantization scale;
• computer-executable instructions for performing variable length coding on the quantized moving image signal;
• computer-executable instructions for detecting an activity of the input moving image signal;
• computer-executable instructions for determining the quantization scale on the basis of the amount of variable length codes obtained from performing variable length coding on the quantized moving image signal;
• computer-executable instructions for changing the determined quantization scale on the basis of the detected activity, and setting the changed quantization scale as the quantization scale;
• computer-executable instructions for detecting, on the basis of the amount of variable length codes, the filling level of a virtual buffer in a decoder which decodes the coded moving image signal;
• and
• computer-executable instructions for performing control, according to the detected filling level, as to whether the determined quantization scale is to be changed on the basis of the activity.