Abstract: An intra prediction encoding control method used in intra prediction encoding having a plurality of prediction modes and prediction block sizes, wherein the prediction mode and the prediction block size each can be switched when encoding is performed. The method includes a step of computing a flatness degree index which indicates a degree of flatness of a target area for encoding; a step of determining a prediction block size used in intra prediction encoding of the target area, in accordance with the computed flatness degree index; and a step of selecting a prediction mode used in the intra prediction encoding of the target area, for the determined prediction block size.

Abstract: A video bitrate control method and apparatus that control a generated bitrate of a picture to be encoded, based on an initial value of an allocation bitrate that is previously given to each picture are provided, wherein a difference between an allocation bitrate and an actually generated bitrate of a picture that has been encoded is obtained as an error bitrate, one of a maximum value and a minimum value of the allocation bitrate is selected for a plurality of subsequent pictures, as an allowable correction range, based on the sign of the error bitrate, the maximum value and the minimum value of the allocation bitrate being calculated based on the initial value of the allocation bitrate and a previously given constant, a difference between the allowable correction range and the allocation bitrate is obtained for the plurality of pictures, as an allowable variation bitrate, the ratio of the sum of allowable variation bitrates and the error bitrate is obtained as an update rate, a variation bitrate for the allo

Abstract: An encoding bit-rate control method used in video encoding in which intraframe prediction and interframe prediction are switchably used. The method includes measuring an amount of code generated for quantized information and an amount of code generated for non-quantized information for the picture which has been encoded; computing a ratio of the amount of code generated for the non-quantized information to the total amount of generated code, based on the above measured amounts of code; and determining a target amount of code of an encoding target picture by using the computed ratio of the amount of code generated for the non-quantized information.

Abstract: In a code amount estimating method, when encoding quantized values of coefficients of a larger-sized orthogonal transformation than an orthogonal transformation size assigned to a variable length encoding table, the quantized values are rearranged in a one-dimensional form, so as to obtain run-level sets. The number of groups is computed based on a proportion between an orthogonal transformation area corresponding to the orthogonal transformation size assigned to the variable length encoding table and an orthogonal transformation area for an encoding target. The Run-Level sets are classified into groups having the number of groups. Each Run is divided by the number of groups, and the obtained quotient is set as Run. A code length of each Run-Level set in each group is determined by referring to the variable length encoding table. The amount of generated code is estimated to be the total sum of the code lengths of all groups.

Abstract: A motion vector search method used in video encoding which performs motion-compensated prediction. The method includes inputting a motion vector which has been searched for with respect to an encoding target block; computing a motion vector having a minimum overhead cost which minimizes the amount of code generated for the motion vector of the encoding target block; limiting a search area based on the input motion vector and the motion vector having the minimum overhead cost; and searching for a motion vector by searching only the limited search area. It is possible to compute a predicted vector of the encoding target block based on a motion vector of an already-encoded block in the vicinity of the target block, and determine the computed predicted vector to be the motion vector having the minimum overhead cost.

Abstract: An intra prediction encoding control method used in intra prediction encoding having a plurality of prediction modes and prediction block sizes, wherein the prediction mode and the prediction block size each can be switched when encoding is performed. The method includes a step of computing a flatness degree index which indicates a degree of flatness of a target area for encoding; a step of determining a prediction block size used in intra prediction encoding of the target area, in accordance with the computed flatness degree index; and a step of selecting a prediction mode used in the intra prediction encoding of the target area, for the determined prediction block size.

Abstract: A quantization control method used in a video encoding which encodes a video image and performs control for making an encoding bit rate approach a predetermined target bit rate. The quantization control method includes measuring a differential amount of code between a target amount of code and an amount of generated code; determining whether or not a predetermined condition has occurred; determining, when it is determined that the condition has occurred, a variation for an amount of feedback which increases or decreases a quantization step size, and changing the amount of feedback based on the determined variation; and increasing or decreasing the quantization step size based on the measured differential amount of code and the changed amount of feedback. If there are a plurality of the predetermined conditions, a final variation for the amount of feedback may be determined by applying a specific operation to variations for the amount of feedback, which are determined for the individual conditions.