An audio signal rendering method comprising: receiving flag information, and multichannel signals including a height input channel signal and a horizontal input channel signal, wherein the multichannel signals include at least one of a first frame or a second frame, wherein the first frame, the second frame, and the flag information are based on a predetermined time unit; obtaining a first downmix matrix for three-dimensional rendering over an output layout; obtaining a second downmix matrix for two-dimensional rendering over the output layout; and selecting one downmix matrix between the first downmix matrix and the second downmix matrix based on the flag information; rendering the multichannel signals including the height input channel signal and the horizontal input channel signal, using the selected downmix matrix, so as to provide a sound image having a sense of elevation via a plurality of output channel signals according to the output layout, wherein the output layout is 5.1 channel format, wherein a power of the rendered multichannel signals is preserved, wherein the first downmix matrix and the second downmix matrix are for different elevation rendering for the height input channel signal, the first frame has an applause sound characteristic, and the second frame has a general sound characteristic, wherein the first frame is 2D rendered using the second downmix matrix in case that the flag information of the first frame indicates the applause sound characteristic, and wherein the second frame is 3D rendered using the first downmix matrix in case that the flag information of the second frame indicates the general sound characteristic. receiving flag information, and multichannel signals including a height input channel signal and a horizontal input channel signal, wherein the multichannel signals include at least one of a first frame or a second frame, wherein the first frame, the second frame, and the flag information are based on a predetermined time unit; obtaining a first downmix matrix for three-dimensional rendering over an output layout; obtaining a second downmix matrix for two-dimensional rendering over the output layout; and selecting one downmix matrix between the first downmix matrix and the second downmix matrix based on the flag information; rendering the multichannel signals including the height input channel signal and the horizontal input channel signal, using the selected downmix matrix, so as to provide a sound image having a sense of elevation via a plurality of output channel signals according to the output layout, wherein the output layout is 5.1 channel format, wherein a power of the rendered multichannel signals is preserved, wherein the first downmix matrix and the second downmix matrix are for different elevation rendering for the height input channel signal, the first frame has an applause sound characteristic, and the second frame has a general sound characteristic, wherein the first frame is 2D rendered using the second downmix matrix in case that the flag information of the first frame indicates the applause sound characteristic, and wherein the second frame is 3D rendered using the first downmix matrix in case that the flag information of the second frame indicates the general sound characteristic.