/////////////////////////////////////////////////////////////////////////                                                             ////////  JPEG Encoder Unit                                          ////////                                                             ////////  Author: Richard Herveille                                  ////////          richard@asics.ws                                   ////////          www.asics.ws                                       ////////                                                             /////////////////////////////////////////////////////////////////////////////                                                             //////// Copyright (C) 2002 Richard Herveille                        ////////                    richard@asics.ws                         ////////                                                             //////// This source file may be used and distributed without        //////// restriction provided that this copyright statement is not   //////// removed from the file and that any derivative work contains //////// the original copyright notice and the associated disclaimer.////////                                                             ////////     THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY     //////// EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED   //////// TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS   //////// FOR A PARTICULAR PURPOSE. IN NO EVENT SHALL THE AUTHOR      //////// OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,         //////// INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES    //////// (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE   //////// GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR        //////// BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF  //////// LIABILITY, WHETHER IN  CONTRACT, STRICT LIABILITY, OR TORT  //////// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT  //////// OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE         //////// POSSIBILITY OF SUCH DAMAGE.                                 ////////                                                             ///////////////////////////////////////////////////////////////////////////  CVS Log////  $Id: jpeg_encoder.v,v 1.3 2002/10/31 12:51:44 rherveille Exp $////  $Date: 2002/10/31 12:51:44 $//  $Revision: 1.3 $//  $Author: rherveille $//  $Locker:  $//  $State: Exp $//// Change History://               $Log: jpeg_encoder.v,v $//               Revision 1.3  2002/10/31 12:51:44  rherveille//               *** empty log message ***////               Revision 1.2  2002/10/23 18:58:51  rherveille//               Fixed a bug in the zero-run (run-length-coder)////               Revision 1.1  2002/10/23 09:07:01  rherveille//               Improved many files.//               Fixed some bugs in Run-Length-Encoder.//               Removed dependency on ud_cnt and ro_cnt.//               Started (Motion)JPEG hardware encoder project.////synopsys translate_off`include "timescale.v"//synopsys translate_onmodule jpeg_encoder(	clk,	ena,	rst,	dstrb,	din,	qnt_val,	qnt_cnt,	size,	rlen,	amp,	douten);	//	// parameters	//	////////////////////////////////////////////////////////////////////	//                                                                //	// ITU-T.81, ITU-T.83 & Coefficient resolution notes              //	//                                                                //	////////////////////////////////////////////////////////////////////	//                                                                //	// Worst case error (all input values -128) is                    //	// zero (i.e. no errors) when using 15bit coefficients            //	//                                                                //	// Using less bits for the coefficients produces a biterror       //	// approx. equal to (15 - used_coefficient-bits).                 //	// i.e. 14bit coefficients, errors in dout-bit[0] only            //	//      13bit coefficients, errors in dout-bits[1:0]              //	//      12bit coefficients, errors in dout-bits[2:0] etc.         //	// Tests with real non-continous tone image data have shown that  //	// even when using 13bit coefficients errors remain in the lsb    //	// only (i.e. dout-bit[0]                                         //	//                                                                //	// The amount of coefficient-bits needed is dependent on the      //	// desired quality.                                               //	// The JPEG-standard compliance specs.(ITU-T.83) prescribe        //	// that the output of the combined DCT AND Quantization unit      //	// shall not exceed 1 for the desired quality.                    //	//                                                                //	// This means for high quantization levels, lesser bits           //	// for the DCT unit can be used.                                  //	//                                                                //	// Looking at the recommended "quantization tables for generic    //	// compliance testing of DCT-based processes" (ITU-T.83 annex B)  //	// it can be noticed that relatively large quantization values    //	// are being used. Errors in the lower-order bits should          //	// therefore not be visible.                                      //	// Tests with real continuous and non-continous tone image data   //	// have shown that when using the examples quantization tables    //	// from ITU-T.81 annex K 10bit coefficients are sufficient to     //	// comply to the ITU-T.83 specs. Compliance tests have been met   //	// using as little as 9bit coefficients.                          //	// For certain applications some of the lower-order bits could    //	// actually be discarded. When looking at the luminance and       //	// chrominance example quantization tables (ITU-T.81 annex K)     //	// it can be seen that the smallest quantization value is ten     //	// (qnt_val_min = 10). This means that the lowest 2bits can be    //	// discarded (set to zero '0') without having any effect on the   //	// final result. In this example 11 bit or 12 bit coefficients    //	// would be sufficient.                                           //	//                                                                //	////////////////////////////////////////////////////////////////////	parameter coef_width = 11;	parameter di_width = 8; // no function yet	//	// inputs & outputs	//	input clk;                      // system clock	input ena;                      // clock enable	input rst;                      // active low asynchronous reset	input dstrb;                    // data-strobe. Present dstrb 1clk-cycle before data block	input [di_width-1:0] din;	input [7:0]          qnt_val;   // quantization value	output [ 5:0] qnt_cnt;          // quantization value address		output [ 3:0] size;    // size	output [ 3:0] rlen;    // run-length	output [11:0] amp;     // amplitude	output        douten;  // data output enable	//	// variables	//	wire fdct_doe, qnr_doe;	wire [11:0] fdct_dout;	reg  [11:0] dfdct_dout;	wire [10:0] qnr_dout;	reg         dqnr_doe;	//	// module body	//	// Hookup FDCT & ZigZag module	fdct #(coef_width, di_width, 12)	fdct_zigzag(		.clk(clk),		.ena(ena),		.rst(rst),		.dstrb(dstrb),		.din(din),		.dout(fdct_dout),		.douten(fdct_doe)	);	// delay 'fdct_dout' => wait for synchronous quantization RAM/ROM	always @(posedge clk)	  if(ena)	    dfdct_dout <= #1 fdct_dout;	// Hookup QNR (Quantization and Rounding) unit	jpeg_qnr	qnr(		.clk(clk),		.ena(ena),		.rst(rst),		.dstrb(fdct_doe),		.din(dfdct_dout),		.qnt_val(qnt_val),		.qnt_cnt(qnt_cnt),		.dout(qnr_dout),		.douten(qnr_doe)	);	// delay douten 1 clk_cycle => account for delayed fdct_res & qnt_val	always @(posedge clk)	  if(ena)	    dqnr_doe <= #1 qnr_doe;	//	// TODO: Insert DC differential generator here.	//	wire [11:0] dc_diff_dout = {qnr_dout[10], qnr_dout};	wire        dc_diff_doe = dqnr_doe;	// Hookup Run Length Encoder	jpeg_rle	rle(		.clk(clk),		.ena(ena),		.rst(rst),		.dstrb(dc_diff_doe),		.din(dc_diff_dout),		.size(size),		.rlen(rlen),		.amp(amp),		.douten(douten),		.bstart()	);endmodule