CSJ2K.j2k.entropy.encoder.StdEntropyCoder.rawSigProgPass C# (CSharp) Method

rawSigProgPass() static private method

Performs the significance propagation pass on the specified data and bit-plane, without using the arithmetic coder. It codes all insignificant samples which have, at least, one of its immediate eight neighbors already significant, using the ZC and SC primitives as needed. It toggles the "visited" state bit to 1 for all those samples.

In this method, the arithmetic coder is bypassed, and raw bits are directly written in the bit stream (useful when distribution are close to uniform, for intance, at high bit-rates and at lossless compression).

static private rawSigProgPass ( CSJ2K.j2k.wavelet.analysis.CBlkWTData srcblk, CSJ2K.j2k.entropy.encoder.BitToByteOutput bout, bool doterm, int bp, int state, int fs, int ratebuf, int pidx, int ltpidx, int options ) : int
srcblk CSJ2K.j2k.wavelet.analysis.CBlkWTData The code-block data to code /// ///
bout CSJ2K.j2k.entropy.encoder.BitToByteOutput The bit based output /// ///
doterm bool If true the bit based output is byte aligned after the /// end of the pass. /// ///
bp int The bit-plane to code /// ///
state int The state information for the code-block /// ///
fs int The distortion estimation lookup table for SC /// ///
ratebuf int The buffer where to store the rate (i.e. coded lenth) at /// the end of this coding pass. /// ///
pidx int The coding pass index. Is the index in the 'ratebuf' array /// where to store the coded length after this coding pass. /// ///
ltpidx int The index of the last pass that was terminated, or /// negative if none. /// ///
options int The bitmask of entropy coding options to apply to the /// code-block /// ///
return int
		static private int rawSigProgPass(CBlkWTData srcblk, BitToByteOutput bout, bool doterm, int bp, int[] state, int[] fs, int[] ratebuf, int pidx, int ltpidx, int options)
		{
			int j, sj; // The state index for line and stripe
			int k, sk; // The data index for line and stripe
			int dscanw; // The data scan-width
			int sscanw; // The state scan-width
			int jstep; // Stripe to stripe step for 'sj'
			int kstep; // Stripe to stripe step for 'sk'
			int stopsk; // The loop limit on the variable sk
			int csj; // Local copy (i.e. cached) of 'state[j]'
			int mask; // The mask for the current bit-plane
			int nsym = 0; // Number of symbol
			int sym; // The symbol to code
			int[] data; // The data buffer
			int dist; // The distortion reduction for this pass
			int shift; // Shift amount for distortion
			int upshift; // Shift left amount for distortion
			int downshift; // Shift right amount for distortion
			int normval; // The normalized sample magnitude value
			int s; // The stripe index
			bool causal; // Flag to indicate if stripe-causal context
			// formation is to be used
			int nstripes; // The number of stripes in the code-block
			int sheight; // Height of the current stripe
			int off_ul, off_ur, off_dr, off_dl; // offsets
			
			// Initialize local variables
			dscanw = srcblk.scanw;
			sscanw = srcblk.w + 2;
			jstep = sscanw * CSJ2K.j2k.entropy.StdEntropyCoderOptions.STRIPE_HEIGHT / 2 - srcblk.w;
			kstep = dscanw * CSJ2K.j2k.entropy.StdEntropyCoderOptions.STRIPE_HEIGHT - srcblk.w;
			mask = 1 << bp;
			data = (int[]) srcblk.Data;
			nstripes = (srcblk.h + CSJ2K.j2k.entropy.StdEntropyCoderOptions.STRIPE_HEIGHT - 1) / CSJ2K.j2k.entropy.StdEntropyCoderOptions.STRIPE_HEIGHT;
			dist = 0;
			// We use the MSE_LKP_BITS-1 bits below the bit just coded for
			// distortion estimation.
			shift = bp - (MSE_LKP_BITS - 1);
			upshift = (shift >= 0)?0:- shift;
			downshift = (shift <= 0)?0:shift;
			causal = (options & CSJ2K.j2k.entropy.StdEntropyCoderOptions.OPT_VERT_STR_CAUSAL) != 0;
			
			// Pre-calculate offsets in 'state' for neighbors
			off_ul = - sscanw - 1; // up-left
			off_ur = - sscanw + 1; // up-right
			off_dr = sscanw + 1; // down-right
			off_dl = sscanw - 1; // down-left
			
			// Code stripe by stripe
			sk = srcblk.offset;
			sj = sscanw + 1;
			for (s = nstripes - 1; s >= 0; s--, sk += kstep, sj += jstep)
			{
				sheight = (s != 0)?CSJ2K.j2k.entropy.StdEntropyCoderOptions.STRIPE_HEIGHT:srcblk.h - (nstripes - 1) * CSJ2K.j2k.entropy.StdEntropyCoderOptions.STRIPE_HEIGHT;
				stopsk = sk + srcblk.w;
				// Scan by set of 1 stripe column at a time
				for (; sk < stopsk; sk++, sj++)
				{
					// Do half top of column
					j = sj;
					csj = state[j];
					// If any of the two samples is not significant and has a
					// non-zero context (i.e. some neighbor is significant) we can 
					// not skip them
					if ((((~ csj) & (csj << 2)) & SIG_MASK_R1R2) != 0)
					{
						k = sk;
						// Scan first row
						if ((csj & (STATE_SIG_R1 | STATE_NZ_CTXT_R1)) == STATE_NZ_CTXT_R1)
						{
							// Apply zero coding
							sym = SupportClass.URShift((data[k] & mask), bp);
							bout.writeBit(sym);
							nsym++;
							if (sym != 0)
							{
								// Became significant
								// Apply sign coding
								sym = SupportClass.URShift(data[k], 31);
								bout.writeBit(sym);
								nsym++;
								// Update state information (significant bit,
								// visited bit, neighbor significant bit of
								// neighbors, non zero context of neighbors, sign
								// of neighbors)
								if (!causal)
								{
									// If in causal mode do not change contexts of 
									// previous stripe.
									state[j + off_ul] |= STATE_NZ_CTXT_R2 | STATE_D_DR_R2;
									state[j + off_ur] |= STATE_NZ_CTXT_R2 | STATE_D_DL_R2;
								}
								// Update sign state information of neighbors
								if (sym != 0)
								{
									csj |= STATE_SIG_R1 | STATE_VISITED_R1 | STATE_NZ_CTXT_R2 | STATE_V_U_R2 | STATE_V_U_SIGN_R2;
									if (!causal)
									{
										// If in causal mode do not change
										// contexts of previous stripe.
										state[j - sscanw] |= STATE_NZ_CTXT_R2 | STATE_V_D_R2 | STATE_V_D_SIGN_R2;
									}
									state[j + 1] |= STATE_NZ_CTXT_R1 | STATE_NZ_CTXT_R2 | STATE_H_L_R1 | STATE_H_L_SIGN_R1 | STATE_D_UL_R2;
									state[j - 1] |= STATE_NZ_CTXT_R1 | STATE_NZ_CTXT_R2 | STATE_H_R_R1 | STATE_H_R_SIGN_R1 | STATE_D_UR_R2;
								}
								else
								{
									csj |= STATE_SIG_R1 | STATE_VISITED_R1 | STATE_NZ_CTXT_R2 | STATE_V_U_R2;
									if (!causal)
									{
										// If in causal mode do not change
										// contexts of previous stripe.
										state[j - sscanw] |= STATE_NZ_CTXT_R2 | STATE_V_D_R2;
									}
									state[j + 1] |= STATE_NZ_CTXT_R1 | STATE_NZ_CTXT_R2 | STATE_H_L_R1 | STATE_D_UL_R2;
									state[j - 1] |= STATE_NZ_CTXT_R1 | STATE_NZ_CTXT_R2 | STATE_H_R_R1 | STATE_D_UR_R2;
								}
								// Update distortion
								normval = (data[k] >> downshift) << upshift;
								dist += fs[normval & ((1 << (MSE_LKP_BITS - 1)) - 1)];
							}
							else
							{
								csj |= STATE_VISITED_R1;
							}
						}
						if (sheight < 2)
						{
							state[j] = csj;
							continue;
						}
						// Scan second row
						if ((csj & (STATE_SIG_R2 | STATE_NZ_CTXT_R2)) == STATE_NZ_CTXT_R2)
						{
							k += dscanw;
							// Apply zero coding
							sym = SupportClass.URShift((data[k] & mask), bp);
							bout.writeBit(sym);
							nsym++;
							if (sym != 0)
							{
								// Became significant
								// Apply sign coding
								sym = SupportClass.URShift(data[k], 31);
								bout.writeBit(sym);
								nsym++;
								// Update state information (significant bit,
								// visited bit, neighbor significant bit of
								// neighbors, non zero context of neighbors, sign
								// of neighbors)
								state[j + off_dl] |= STATE_NZ_CTXT_R1 | STATE_D_UR_R1;
								state[j + off_dr] |= STATE_NZ_CTXT_R1 | STATE_D_UL_R1;
								// Update sign state information of neighbors
								if (sym != 0)
								{
									csj |= STATE_SIG_R2 | STATE_VISITED_R2 | STATE_NZ_CTXT_R1 | STATE_V_D_R1 | STATE_V_D_SIGN_R1;
									state[j + sscanw] |= STATE_NZ_CTXT_R1 | STATE_V_U_R1 | STATE_V_U_SIGN_R1;
									state[j + 1] |= STATE_NZ_CTXT_R1 | STATE_NZ_CTXT_R2 | STATE_D_DL_R1 | STATE_H_L_R2 | STATE_H_L_SIGN_R2;
									state[j - 1] |= STATE_NZ_CTXT_R1 | STATE_NZ_CTXT_R2 | STATE_D_DR_R1 | STATE_H_R_R2 | STATE_H_R_SIGN_R2;
								}
								else
								{
									csj |= STATE_SIG_R2 | STATE_VISITED_R2 | STATE_NZ_CTXT_R1 | STATE_V_D_R1;
									state[j + sscanw] |= STATE_NZ_CTXT_R1 | STATE_V_U_R1;
									state[j + 1] |= STATE_NZ_CTXT_R1 | STATE_NZ_CTXT_R2 | STATE_D_DL_R1 | STATE_H_L_R2;
									state[j - 1] |= STATE_NZ_CTXT_R1 | STATE_NZ_CTXT_R2 | STATE_D_DR_R1 | STATE_H_R_R2;
								}
								// Update distortion
								normval = (data[k] >> downshift) << upshift;
								dist += fs[normval & ((1 << (MSE_LKP_BITS - 1)) - 1)];
							}
							else
							{
								csj |= STATE_VISITED_R2;
							}
						}
						state[j] = csj;
					}
					// Do half bottom of column
					if (sheight < 3)
						continue;
					j += sscanw;
					csj = state[j];
					// If any of the two samples is not significant and has a
					// non-zero context (i.e. some neighbor is significant) we can 
					// not skip them
					if ((((~ csj) & (csj << 2)) & SIG_MASK_R1R2) != 0)
					{
						k = sk + (dscanw << 1);
						// Scan first row
						if ((csj & (STATE_SIG_R1 | STATE_NZ_CTXT_R1)) == STATE_NZ_CTXT_R1)
						{
							sym = SupportClass.URShift((data[k] & mask), bp);
							bout.writeBit(sym);
							nsym++;
							if (sym != 0)
							{
								// Became significant
								// Apply sign coding
								sym = SupportClass.URShift(data[k], 31);
								bout.writeBit(sym);
								nsym++;
								// Update state information (significant bit,
								// visited bit, neighbor significant bit of
								// neighbors, non zero context of neighbors, sign
								// of neighbors)
								state[j + off_ul] |= STATE_NZ_CTXT_R2 | STATE_D_DR_R2;
								state[j + off_ur] |= STATE_NZ_CTXT_R2 | STATE_D_DL_R2;
								// Update sign state information of neighbors
								if (sym != 0)
								{
									csj |= STATE_SIG_R1 | STATE_VISITED_R1 | STATE_NZ_CTXT_R2 | STATE_V_U_R2 | STATE_V_U_SIGN_R2;
									state[j - sscanw] |= STATE_NZ_CTXT_R2 | STATE_V_D_R2 | STATE_V_D_SIGN_R2;
									state[j + 1] |= STATE_NZ_CTXT_R1 | STATE_NZ_CTXT_R2 | STATE_H_L_R1 | STATE_H_L_SIGN_R1 | STATE_D_UL_R2;
									state[j - 1] |= STATE_NZ_CTXT_R1 | STATE_NZ_CTXT_R2 | STATE_H_R_R1 | STATE_H_R_SIGN_R1 | STATE_D_UR_R2;
								}
								else
								{
									csj |= STATE_SIG_R1 | STATE_VISITED_R1 | STATE_NZ_CTXT_R2 | STATE_V_U_R2;
									state[j - sscanw] |= STATE_NZ_CTXT_R2 | STATE_V_D_R2;
									state[j + 1] |= STATE_NZ_CTXT_R1 | STATE_NZ_CTXT_R2 | STATE_H_L_R1 | STATE_D_UL_R2;
									state[j - 1] |= STATE_NZ_CTXT_R1 | STATE_NZ_CTXT_R2 | STATE_H_R_R1 | STATE_D_UR_R2;
								}
								// Update distortion
								normval = (data[k] >> downshift) << upshift;
								dist += fs[normval & ((1 << (MSE_LKP_BITS - 1)) - 1)];
							}
							else
							{
								csj |= STATE_VISITED_R1;
							}
						}
						if (sheight < 4)
						{
							state[j] = csj;
							continue;
						}
						if ((csj & (STATE_SIG_R2 | STATE_NZ_CTXT_R2)) == STATE_NZ_CTXT_R2)
						{
							k += dscanw;
							// Apply zero coding
							sym = SupportClass.URShift((data[k] & mask), bp);
							bout.writeBit(sym);
							nsym++;
							if (sym != 0)
							{
								// Became significant
								// Apply sign coding
								sym = SupportClass.URShift(data[k], 31);
								bout.writeBit(sym);
								nsym++;
								// Update state information (significant bit,
								// visited bit, neighbor significant bit of
								// neighbors, non zero context of neighbors, sign
								// of neighbors)
								state[j + off_dl] |= STATE_NZ_CTXT_R1 | STATE_D_UR_R1;
								state[j + off_dr] |= STATE_NZ_CTXT_R1 | STATE_D_UL_R1;
								// Update sign state information of neighbors
								if (sym != 0)
								{
									csj |= STATE_SIG_R2 | STATE_VISITED_R2 | STATE_NZ_CTXT_R1 | STATE_V_D_R1 | STATE_V_D_SIGN_R1;
									state[j + sscanw] |= STATE_NZ_CTXT_R1 | STATE_V_U_R1 | STATE_V_U_SIGN_R1;
									state[j + 1] |= STATE_NZ_CTXT_R1 | STATE_NZ_CTXT_R2 | STATE_D_DL_R1 | STATE_H_L_R2 | STATE_H_L_SIGN_R2;
									state[j - 1] |= STATE_NZ_CTXT_R1 | STATE_NZ_CTXT_R2 | STATE_D_DR_R1 | STATE_H_R_R2 | STATE_H_R_SIGN_R2;
								}
								else
								{
									csj |= STATE_SIG_R2 | STATE_VISITED_R2 | STATE_NZ_CTXT_R1 | STATE_V_D_R1;
									state[j + sscanw] |= STATE_NZ_CTXT_R1 | STATE_V_U_R1;
									state[j + 1] |= STATE_NZ_CTXT_R1 | STATE_NZ_CTXT_R2 | STATE_D_DL_R1 | STATE_H_L_R2;
									state[j - 1] |= STATE_NZ_CTXT_R1 | STATE_NZ_CTXT_R2 | STATE_D_DR_R1 | STATE_H_R_R2;
								}
								// Update distortion
								normval = (data[k] >> downshift) << upshift;
								dist += fs[normval & ((1 << (MSE_LKP_BITS - 1)) - 1)];
							}
							else
							{
								csj |= STATE_VISITED_R2;
							}
						}
						state[j] = csj;
					}
				}
			}
			
			// Get length and terminate if needed
			if (doterm)
			{
				ratebuf[pidx] = bout.terminate();
			}
			else
			{
				ratebuf[pidx] = bout.length();
			}
			// Add length of previous segments, if any
			if (ltpidx >= 0)
			{
				ratebuf[pidx] += ratebuf[ltpidx];
			}
			
			// Return the reduction in distortion
			return dist;
		}