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//--------------------------------------------------------------------------------------------------
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// Design : nova
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// Author(s) : Ke Xu
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// Email : eexuke@yahoo.com
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// File : QP_decoding.v
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// Generated : June 7, 2005
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// Copyright (C) 2008 Ke Xu
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//-------------------------------------------------------------------------------------------------
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// Description
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// QPy:the luma quantisation parameter
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// QPi:the intermediate quantisation parameter derived from QPy
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// QPc:the chroma quantisation parameter derived from QPi on Table 8-13,Page136
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//-------------------------------------------------------------------------------------------------
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// Revise log
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// 1. March 21,2006
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// Input signals slice_qp_delta and mb_qp_delta are removed, using
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// exp_golomb_decoding_output_5to0 instead since these two signals are latched at clock
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// rising edge which is too late for computation. So use exp_golomb_decoding_output_5to0 directly
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//-------------------------------------------------------------------------------------------------
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// synopsys translate_off
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`include "timescale.v"
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// synopsys translate_on
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`include "nova_defines.v"
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module QP_decoding (clk,reset_n,slice_header_state,slice_data_state,pic_init_qp_minus26,
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exp_golomb_decoding_output_5to0,chroma_qp_index_offset,QPy,QPc);
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input clk,reset_n;
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input [3:0] slice_header_state;
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input [3:0] slice_data_state;
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input [5:0] pic_init_qp_minus26;
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input [5:0] exp_golomb_decoding_output_5to0;
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input [4:0] chroma_qp_index_offset;
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output [5:0] QPy,QPc;
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reg [5:0] QPy,QPc;
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always @ (posedge clk)
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if (reset_n == 0)
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QPy <= 0;
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else if (slice_header_state == `slice_qp_delta_s)
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QPy <= 26 + pic_init_qp_minus26 + exp_golomb_decoding_output_5to0;
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else if (slice_data_state == `mb_qp_delta_s)
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QPy <= QPy + exp_golomb_decoding_output_5to0;
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wire [5:0] QPi;
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assign QPi = QPy + {1'b0,chroma_qp_index_offset};
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always @ (posedge clk)
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if (reset_n == 0)
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QPc <= 0;
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else
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begin
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if (QPi < 30)
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QPc <= QPi;
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else
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case (QPi)
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30 :QPc <= 29;
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31 :QPc <= 30;
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32 :QPc <= 31;
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33,34 :QPc <= 32;
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35 :QPc <= 33;
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36,37 :QPc <= 34;
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38,39 :QPc <= 35;
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40,41 :QPc <= 36;
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42,43,44:QPc <= 37;
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45,46,47:QPc <= 38;
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default :QPc <= 39;
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endcase
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end
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endmodule
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