# 4.2.4.3 Inverse Quantization/DWT

The following sections present the three-level inverse DWT of the Y component data. The inverse DWT process follows the steps shown in the figure illustrating three-level DWT decomposition in section 3.1.8.1.4, in reverse order. The inverse DWT steps for the Cb and Cr components are the same as for the Y component, so the intermediate data dumps for these two components have been omitted, but their final reconstructed data is presented in sections 4.2.4.4 and 4.2.4.5.

Microsoft RDP 7.1 and Microsoft RDP 8.0 both use 11.5 fixed-point integers for IDWT and color conversion, while Microsoft RDP 8.1 uses 12.4 fixed-point integers. This is due to differences in dequantization (section 3.1.8.2.3). The example data in the following sections is shown for both 11.5 and 12.4 fixed-point integers.