Patent ID: 8107528
Filing Date: 2012-01-31
Classification: H04N

Abstract:
1. A picture processing apparatus for encoding picture data, comprising: obtaining means for obtaining, from picture data output by a decoder decoding an intraframe stream with a high bit rate, information about a past encoding process performed on the picture data, the information including picture type, a bit rate in an immediate preceding encoding process and a past quantization value, wherein the picture type including an I-picture, a P-picture and a B-picture; setting means for setting a quantization value; quantization means for performing quantization based on the quantization value set by the setting means; and encoding means for encoding coefficient data quantized by the quantization means into a data stream with a low bit rate, wherein, when the picture type is not the I-picture, the setting means (a) selects a minimum quantization value based upon the bit rate in the immediate preceding encoding process, from a plurality of minimum quantization values each of which is set according to a bit rate, as a minimum value in a range of quantization values, (b) determines when the past quantization value, obtained from said obtaining means, is smaller than the selected minimum quantization value, (c) when the past quantization is smaller, sets the quantization value at a value equal to the selected minimum quantization value and (d) when the past quantization is not smaller, sets the quantization value to the past quantization value, wherein, when the picture type is the I-picture, the setting means sets the larger value of the past and the selected minimum quantization values as the quantization value.