Method for generating prediction block in amvp mode

Abstract

A transmission method for data comprising a bitstream for an image, the method including obtaining the bitstream for the image; and transmitting the data comprising the bitstream, wherein the bitstream is decoded by a decoding device, wherein the image decoding device is configured to derive, by a motion compensation predictor, motion information using effective spatial and temporal merge candidates of a current prediction unit; generate, by the motion compensation predictor, a prediction block of the current prediction unit using the motion information; entropy decode, by an entropy decoder, a bit stream to generate a quantized coefficient sequence, inversely scan, by an inverse quantizer/inverse transformer, the quantized coefficient sequence to generate a quantized block, inversely quantize, by the inverse quantizer/inverse transformer, the quantized block to generate a transformed block using a quantization parameter, and inversely transform, by the inverse quantizer/inverse transformer, the transformed block to generate a residual block; and generate, by an adder, a reconstructed block using the prediction block and the residual block, wherein a motion vector of the temporal merge candidate is a motion vector of a temporal merge candidate block within a temporal merge candidate picture, and the quantization parameter is derived using an average of two effective quantization parameters among a left quantization parameter, an upper quantization parameter and a previous quantization parameter of a current coding unit, wherein when the quantized block is larger than a predetermined size, the quantized block is generated with plurality of subblocks, and a scan pattern of inversely scanning for the plurality of subblocks is the same as a scan pattern of inversely scanning for quantized coefficients of each subblock, and wherein a scanning scheme for inversely scanning the quantized coefficients is determined according to an intra-prediction mode and a size of a transform unit.