A method of decoding implemented by a video decoder, comprising: receiving, by the video decoder, a video bitstream, wherein the video bitstream comprises a first picture parameter set and a second picture parameter set each referring to the same sequence parameter set; decoding, by the video decoder, the video bitstream to obtain parameters of a conformance window; applying, by the video decoder, the conformance window to a current picture corresponding to the first picture parameter set or the second picture parameter set; wherein the parameters of the conformance window are used to specify samples of pictures referencing the first picture parameter set or the second picture parameter set that are output from the decoding process, in terms of a rectangular region specified in picture coordinates for output; characterized in that each of the first picture parameter set and the second picture parameter set comprises a pic width in luma_samples, a pic_height_in_luma_samples and the parameters of the conformance window, wherein the pic width in luma _samples specifies the width of each decoded picture referencing the corresponding picture parameter set, PPS, in units of luma samples, and the pic_height_in_luma_samples specifies the height of each decoded picture referencing the corresponding PPS in units of luma samples; wherein when the first picture parameter set and the second picture parameter set have the same values of pic width in luma_samples and pic _height in luma samples, respectively, the first picture parameter set and the second picture parameter set have the same values of the parameters of the conformance window. receiving, by the video decoder, a video bitstream, wherein the video bitstream comprises a first picture parameter set and a second picture parameter set each referring to the same sequence parameter set; decoding, by the video decoder, the video bitstream to obtain parameters of a conformance window; applying, by the video decoder, the conformance window to a current picture corresponding to the first picture parameter set or the second picture parameter set; wherein the parameters of the conformance window are used to specify samples of pictures referencing the first picture parameter set or the second picture parameter set that are output from the decoding process, in terms of a rectangular region specified in picture coordinates for output; characterized in that each of the first picture parameter set and the second picture parameter set comprises a pic width in luma_samples, a pic_height_in_luma_samples and the parameters of the conformance window, wherein the pic width in luma _samples specifies the width of each decoded picture referencing the corresponding picture parameter set, PPS, in units of luma samples, and the pic_height_in_luma_samples specifies the height of each decoded picture referencing the corresponding PPS in units of luma samples; wherein when the first picture parameter set and the second picture parameter set have the same values of pic width in luma_samples and pic _height in luma samples, respectively, the first picture parameter set and the second picture parameter set have the same values of the parameters of the conformance window.