Shoaib Ahmed / Mbed 2 deprecated uzairkhan

Final 350 project

Dependencies:   uzair Camera_LS_Y201 F7_Ethernet LCD_DISCO_F746NG NetworkAPI SDFileSystem mbed

includes/jfdctflt.c@0:791a779d6220, 2017-07-31 (annotated)

Committer:
shoaib_ahmed
Date:
Mon Jul 31 09:16:35 2017 +0000
Revision:
0:791a779d6220
final project;

Who changed what in which revision?

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shoaib_ahmed 0:791a779d6220 1 /*
shoaib_ahmed 0:791a779d6220 2 * jfdctflt.c
shoaib_ahmed 0:791a779d6220 3 *
shoaib_ahmed 0:791a779d6220 4 * Copyright (C) 1994-1996, Thomas G. Lane.
shoaib_ahmed 0:791a779d6220 5 * Modified 2003-2015 by Guido Vollbeding.
shoaib_ahmed 0:791a779d6220 6 * This file is part of the Independent JPEG Group's software.
shoaib_ahmed 0:791a779d6220 7 * For conditions of distribution and use, see the accompanying README file.
shoaib_ahmed 0:791a779d6220 8 *
shoaib_ahmed 0:791a779d6220 9 * This file contains a floating-point implementation of the
shoaib_ahmed 0:791a779d6220 10 * forward DCT (Discrete Cosine Transform).
shoaib_ahmed 0:791a779d6220 11 *
shoaib_ahmed 0:791a779d6220 12 * This implementation should be more accurate than either of the integer
shoaib_ahmed 0:791a779d6220 13 * DCT implementations. However, it may not give the same results on all
shoaib_ahmed 0:791a779d6220 14 * machines because of differences in roundoff behavior. Speed will depend
shoaib_ahmed 0:791a779d6220 15 * on the hardware's floating point capacity.
shoaib_ahmed 0:791a779d6220 16 *
shoaib_ahmed 0:791a779d6220 17 * A 2-D DCT can be done by 1-D DCT on each row followed by 1-D DCT
shoaib_ahmed 0:791a779d6220 18 * on each column. Direct algorithms are also available, but they are
shoaib_ahmed 0:791a779d6220 19 * much more complex and seem not to be any faster when reduced to code.
shoaib_ahmed 0:791a779d6220 20 *
shoaib_ahmed 0:791a779d6220 21 * This implementation is based on Arai, Agui, and Nakajima's algorithm for
shoaib_ahmed 0:791a779d6220 22 * scaled DCT. Their original paper (Trans. IEICE E-71(11):1095) is in
shoaib_ahmed 0:791a779d6220 23 * Japanese, but the algorithm is described in the Pennebaker & Mitchell
shoaib_ahmed 0:791a779d6220 24 * JPEG textbook (see REFERENCES section in file README). The following code
shoaib_ahmed 0:791a779d6220 25 * is based directly on figure 4-8 in P&M.
shoaib_ahmed 0:791a779d6220 26 * While an 8-point DCT cannot be done in less than 11 multiplies, it is
shoaib_ahmed 0:791a779d6220 27 * possible to arrange the computation so that many of the multiplies are
shoaib_ahmed 0:791a779d6220 28 * simple scalings of the final outputs. These multiplies can then be
shoaib_ahmed 0:791a779d6220 29 * folded into the multiplications or divisions by the JPEG quantization
shoaib_ahmed 0:791a779d6220 30 * table entries. The AA&N method leaves only 5 multiplies and 29 adds
shoaib_ahmed 0:791a779d6220 31 * to be done in the DCT itself.
shoaib_ahmed 0:791a779d6220 32 * The primary disadvantage of this method is that with a fixed-point
shoaib_ahmed 0:791a779d6220 33 * implementation, accuracy is lost due to imprecise representation of the
shoaib_ahmed 0:791a779d6220 34 * scaled quantization values. However, that problem does not arise if
shoaib_ahmed 0:791a779d6220 35 * we use floating point arithmetic.
shoaib_ahmed 0:791a779d6220 36 */
shoaib_ahmed 0:791a779d6220 37
shoaib_ahmed 0:791a779d6220 38 #define JPEG_INTERNALS
shoaib_ahmed 0:791a779d6220 39 #include "jinclude.h"
shoaib_ahmed 0:791a779d6220 40 #include "jpeglib.h"
shoaib_ahmed 0:791a779d6220 41 #include "jdct.h" /* Private declarations for DCT subsystem */
shoaib_ahmed 0:791a779d6220 42
shoaib_ahmed 0:791a779d6220 43 #ifdef DCT_FLOAT_SUPPORTED
shoaib_ahmed 0:791a779d6220 44
shoaib_ahmed 0:791a779d6220 45
shoaib_ahmed 0:791a779d6220 46 /*
shoaib_ahmed 0:791a779d6220 47 * This module is specialized to the case DCTSIZE = 8.
shoaib_ahmed 0:791a779d6220 48 */
shoaib_ahmed 0:791a779d6220 49
shoaib_ahmed 0:791a779d6220 50 #if DCTSIZE != 8
shoaib_ahmed 0:791a779d6220 51 Sorry, this code only copes with 8x8 DCTs. /* deliberate syntax err */
shoaib_ahmed 0:791a779d6220 52 #endif
shoaib_ahmed 0:791a779d6220 53
shoaib_ahmed 0:791a779d6220 54
shoaib_ahmed 0:791a779d6220 55 /*
shoaib_ahmed 0:791a779d6220 56 * Perform the forward DCT on one block of samples.
shoaib_ahmed 0:791a779d6220 57 *
shoaib_ahmed 0:791a779d6220 58 * cK represents cos(K*pi/16).
shoaib_ahmed 0:791a779d6220 59 */
shoaib_ahmed 0:791a779d6220 60
shoaib_ahmed 0:791a779d6220 61 GLOBAL(void)
shoaib_ahmed 0:791a779d6220 62 jpeg_fdct_float (FAST_FLOAT * data, JSAMPARRAY sample_data, JDIMENSION start_col)
shoaib_ahmed 0:791a779d6220 63 {
shoaib_ahmed 0:791a779d6220 64 FAST_FLOAT tmp0, tmp1, tmp2, tmp3, tmp4, tmp5, tmp6, tmp7;
shoaib_ahmed 0:791a779d6220 65 FAST_FLOAT tmp10, tmp11, tmp12, tmp13;
shoaib_ahmed 0:791a779d6220 66 FAST_FLOAT z1, z2, z3, z4, z5, z11, z13;
shoaib_ahmed 0:791a779d6220 67 FAST_FLOAT *dataptr;
shoaib_ahmed 0:791a779d6220 68 JSAMPROW elemptr;
shoaib_ahmed 0:791a779d6220 69 int ctr;
shoaib_ahmed 0:791a779d6220 70
shoaib_ahmed 0:791a779d6220 71 /* Pass 1: process rows. */
shoaib_ahmed 0:791a779d6220 72
shoaib_ahmed 0:791a779d6220 73 dataptr = data;
shoaib_ahmed 0:791a779d6220 74 for (ctr = 0; ctr < DCTSIZE; ctr++) {
shoaib_ahmed 0:791a779d6220 75 elemptr = sample_data[ctr] + start_col;
shoaib_ahmed 0:791a779d6220 76
shoaib_ahmed 0:791a779d6220 77 /* Load data into workspace */
shoaib_ahmed 0:791a779d6220 78 tmp0 = (FAST_FLOAT) (GETJSAMPLE(elemptr[0]) + GETJSAMPLE(elemptr[7]));
shoaib_ahmed 0:791a779d6220 79 tmp7 = (FAST_FLOAT) (GETJSAMPLE(elemptr[0]) - GETJSAMPLE(elemptr[7]));
shoaib_ahmed 0:791a779d6220 80 tmp1 = (FAST_FLOAT) (GETJSAMPLE(elemptr[1]) + GETJSAMPLE(elemptr[6]));
shoaib_ahmed 0:791a779d6220 81 tmp6 = (FAST_FLOAT) (GETJSAMPLE(elemptr[1]) - GETJSAMPLE(elemptr[6]));
shoaib_ahmed 0:791a779d6220 82 tmp2 = (FAST_FLOAT) (GETJSAMPLE(elemptr[2]) + GETJSAMPLE(elemptr[5]));
shoaib_ahmed 0:791a779d6220 83 tmp5 = (FAST_FLOAT) (GETJSAMPLE(elemptr[2]) - GETJSAMPLE(elemptr[5]));
shoaib_ahmed 0:791a779d6220 84 tmp3 = (FAST_FLOAT) (GETJSAMPLE(elemptr[3]) + GETJSAMPLE(elemptr[4]));
shoaib_ahmed 0:791a779d6220 85 tmp4 = (FAST_FLOAT) (GETJSAMPLE(elemptr[3]) - GETJSAMPLE(elemptr[4]));
shoaib_ahmed 0:791a779d6220 86
shoaib_ahmed 0:791a779d6220 87 /* Even part */
shoaib_ahmed 0:791a779d6220 88
shoaib_ahmed 0:791a779d6220 89 tmp10 = tmp0 + tmp3; /* phase 2 */
shoaib_ahmed 0:791a779d6220 90 tmp13 = tmp0 - tmp3;
shoaib_ahmed 0:791a779d6220 91 tmp11 = tmp1 + tmp2;
shoaib_ahmed 0:791a779d6220 92 tmp12 = tmp1 - tmp2;
shoaib_ahmed 0:791a779d6220 93
shoaib_ahmed 0:791a779d6220 94 /* Apply unsigned->signed conversion. */
shoaib_ahmed 0:791a779d6220 95 dataptr[0] = tmp10 + tmp11 - 8 * CENTERJSAMPLE; /* phase 3 */
shoaib_ahmed 0:791a779d6220 96 dataptr[4] = tmp10 - tmp11;
shoaib_ahmed 0:791a779d6220 97
shoaib_ahmed 0:791a779d6220 98 z1 = (tmp12 + tmp13) * ((FAST_FLOAT) 0.707106781); /* c4 */
shoaib_ahmed 0:791a779d6220 99 dataptr[2] = tmp13 + z1; /* phase 5 */
shoaib_ahmed 0:791a779d6220 100 dataptr[6] = tmp13 - z1;
shoaib_ahmed 0:791a779d6220 101
shoaib_ahmed 0:791a779d6220 102 /* Odd part */
shoaib_ahmed 0:791a779d6220 103
shoaib_ahmed 0:791a779d6220 104 tmp10 = tmp4 + tmp5; /* phase 2 */
shoaib_ahmed 0:791a779d6220 105 tmp11 = tmp5 + tmp6;
shoaib_ahmed 0:791a779d6220 106 tmp12 = tmp6 + tmp7;
shoaib_ahmed 0:791a779d6220 107
shoaib_ahmed 0:791a779d6220 108 /* The rotator is modified from fig 4-8 to avoid extra negations. */
shoaib_ahmed 0:791a779d6220 109 z5 = (tmp10 - tmp12) * ((FAST_FLOAT) 0.382683433); /* c6 */
shoaib_ahmed 0:791a779d6220 110 z2 = ((FAST_FLOAT) 0.541196100) * tmp10 + z5; /* c2-c6 */
shoaib_ahmed 0:791a779d6220 111 z4 = ((FAST_FLOAT) 1.306562965) * tmp12 + z5; /* c2+c6 */
shoaib_ahmed 0:791a779d6220 112 z3 = tmp11 * ((FAST_FLOAT) 0.707106781); /* c4 */
shoaib_ahmed 0:791a779d6220 113
shoaib_ahmed 0:791a779d6220 114 z11 = tmp7 + z3; /* phase 5 */
shoaib_ahmed 0:791a779d6220 115 z13 = tmp7 - z3;
shoaib_ahmed 0:791a779d6220 116
shoaib_ahmed 0:791a779d6220 117 dataptr[5] = z13 + z2; /* phase 6 */
shoaib_ahmed 0:791a779d6220 118 dataptr[3] = z13 - z2;
shoaib_ahmed 0:791a779d6220 119 dataptr[1] = z11 + z4;
shoaib_ahmed 0:791a779d6220 120 dataptr[7] = z11 - z4;
shoaib_ahmed 0:791a779d6220 121
shoaib_ahmed 0:791a779d6220 122 dataptr += DCTSIZE; /* advance pointer to next row */
shoaib_ahmed 0:791a779d6220 123 }
shoaib_ahmed 0:791a779d6220 124
shoaib_ahmed 0:791a779d6220 125 /* Pass 2: process columns. */
shoaib_ahmed 0:791a779d6220 126
shoaib_ahmed 0:791a779d6220 127 dataptr = data;
shoaib_ahmed 0:791a779d6220 128 for (ctr = DCTSIZE-1; ctr >= 0; ctr--) {
shoaib_ahmed 0:791a779d6220 129 tmp0 = dataptr[DCTSIZE*0] + dataptr[DCTSIZE*7];
shoaib_ahmed 0:791a779d6220 130 tmp7 = dataptr[DCTSIZE*0] - dataptr[DCTSIZE*7];
shoaib_ahmed 0:791a779d6220 131 tmp1 = dataptr[DCTSIZE*1] + dataptr[DCTSIZE*6];
shoaib_ahmed 0:791a779d6220 132 tmp6 = dataptr[DCTSIZE*1] - dataptr[DCTSIZE*6];
shoaib_ahmed 0:791a779d6220 133 tmp2 = dataptr[DCTSIZE*2] + dataptr[DCTSIZE*5];
shoaib_ahmed 0:791a779d6220 134 tmp5 = dataptr[DCTSIZE*2] - dataptr[DCTSIZE*5];
shoaib_ahmed 0:791a779d6220 135 tmp3 = dataptr[DCTSIZE*3] + dataptr[DCTSIZE*4];
shoaib_ahmed 0:791a779d6220 136 tmp4 = dataptr[DCTSIZE*3] - dataptr[DCTSIZE*4];
shoaib_ahmed 0:791a779d6220 137
shoaib_ahmed 0:791a779d6220 138 /* Even part */
shoaib_ahmed 0:791a779d6220 139
shoaib_ahmed 0:791a779d6220 140 tmp10 = tmp0 + tmp3; /* phase 2 */
shoaib_ahmed 0:791a779d6220 141 tmp13 = tmp0 - tmp3;
shoaib_ahmed 0:791a779d6220 142 tmp11 = tmp1 + tmp2;
shoaib_ahmed 0:791a779d6220 143 tmp12 = tmp1 - tmp2;
shoaib_ahmed 0:791a779d6220 144
shoaib_ahmed 0:791a779d6220 145 dataptr[DCTSIZE*0] = tmp10 + tmp11; /* phase 3 */
shoaib_ahmed 0:791a779d6220 146 dataptr[DCTSIZE*4] = tmp10 - tmp11;
shoaib_ahmed 0:791a779d6220 147
shoaib_ahmed 0:791a779d6220 148 z1 = (tmp12 + tmp13) * ((FAST_FLOAT) 0.707106781); /* c4 */
shoaib_ahmed 0:791a779d6220 149 dataptr[DCTSIZE*2] = tmp13 + z1; /* phase 5 */
shoaib_ahmed 0:791a779d6220 150 dataptr[DCTSIZE*6] = tmp13 - z1;
shoaib_ahmed 0:791a779d6220 151
shoaib_ahmed 0:791a779d6220 152 /* Odd part */
shoaib_ahmed 0:791a779d6220 153
shoaib_ahmed 0:791a779d6220 154 tmp10 = tmp4 + tmp5; /* phase 2 */
shoaib_ahmed 0:791a779d6220 155 tmp11 = tmp5 + tmp6;
shoaib_ahmed 0:791a779d6220 156 tmp12 = tmp6 + tmp7;
shoaib_ahmed 0:791a779d6220 157
shoaib_ahmed 0:791a779d6220 158 /* The rotator is modified from fig 4-8 to avoid extra negations. */
shoaib_ahmed 0:791a779d6220 159 z5 = (tmp10 - tmp12) * ((FAST_FLOAT) 0.382683433); /* c6 */
shoaib_ahmed 0:791a779d6220 160 z2 = ((FAST_FLOAT) 0.541196100) * tmp10 + z5; /* c2-c6 */
shoaib_ahmed 0:791a779d6220 161 z4 = ((FAST_FLOAT) 1.306562965) * tmp12 + z5; /* c2+c6 */
shoaib_ahmed 0:791a779d6220 162 z3 = tmp11 * ((FAST_FLOAT) 0.707106781); /* c4 */
shoaib_ahmed 0:791a779d6220 163
shoaib_ahmed 0:791a779d6220 164 z11 = tmp7 + z3; /* phase 5 */
shoaib_ahmed 0:791a779d6220 165 z13 = tmp7 - z3;
shoaib_ahmed 0:791a779d6220 166
shoaib_ahmed 0:791a779d6220 167 dataptr[DCTSIZE*5] = z13 + z2; /* phase 6 */
shoaib_ahmed 0:791a779d6220 168 dataptr[DCTSIZE*3] = z13 - z2;
shoaib_ahmed 0:791a779d6220 169 dataptr[DCTSIZE*1] = z11 + z4;
shoaib_ahmed 0:791a779d6220 170 dataptr[DCTSIZE*7] = z11 - z4;
shoaib_ahmed 0:791a779d6220 171
shoaib_ahmed 0:791a779d6220 172 dataptr++; /* advance pointer to next column */
shoaib_ahmed 0:791a779d6220 173 }
shoaib_ahmed 0:791a779d6220 174 }
shoaib_ahmed 0:791a779d6220 175
shoaib_ahmed 0:791a779d6220 176 #endif /* DCT_FLOAT_SUPPORTED */