-
Notifications
You must be signed in to change notification settings - Fork 0
/
Copy pathjo_jpeg.cpp
337 lines (301 loc) · 16.2 KB
/
jo_jpeg.cpp
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
/* public domain Simple, Minimalistic JPEG writer - http://jonolick.com
*
* Quick Notes:
* Based on a javascript jpeg writer
* JPEG baseline (no JPEG progressive)
* input assumes 4-byte RGBX (X is ignored)
*
* Latest revisions:
* 1.50 (2012-18-11) MT safe. Simplified. Optimized. Reduced memory requirements. Zero allocations. No namespace polution. Approx 340 lines code.
* 1.10 (2012-16-11) compile fixes, added docs,
* changed from .h to .cpp (simpler to bootstrap), etc
* 1.00 (2012-02-02) initial release
*
* TODO:
* Optimize
*
* Basic usage:
* char *foo = new char[128*128*4]; // RGBX format, where X is unused
* jo_write_jpg("foo.jpg", foo, 128, 128, 90);
*
* */
#ifndef JO_INCLUDE_JPEG_H
#define JO_INCLUDE_JPEG_H
// To get a header file for this, either cut and paste the header,
// or create jo_jpeg.h, #define JO_JPEG_HEADER_FILE_ONLY, and
// then include jo_jpeg.c from it.
// Returns false on failure
extern bool jo_write_jpg(const char *filename, const void *data, int width, int height, int quality);
#endif // JO_INCLUDE_JPEG_H
#ifndef JO_JPEG_HEADER_FILE_ONLY
#if defined(_MSC_VER) && _MSC_VER >= 0x1400
#define _CRT_SECURE_NO_WARNINGS // suppress warnings about fopen()
#endif
#include <stdio.h>
#include <stdlib.h>
#include <math.h>
static const unsigned char s_jo_ZigZag[] = { 0,1,5,6,14,15,27,28,2,4,7,13,16,26,29,42,3,8,12,17,25,30,41,43,9,11,18,24,31,40,44,53,10,19,23,32,39,45,52,54,20,22,33,38,46,51,55,60,21,34,37,47,50,56,59,61,35,36,48,49,57,58,62,63 };
static void jo_writeBits(FILE *fp, int &bitBuf, int &bitCnt, const unsigned short *bs) {
bitCnt += bs[1];
bitBuf |= bs[0] << (24 - bitCnt);
while(bitCnt >= 8) {
unsigned char c = (bitBuf >> 16) & 255;
putc(c, fp);
if(c == 255) {
putc(0, fp);
}
bitBuf <<= 8;
bitCnt -= 8;
}
}
static void jo_DCT(float &d0, float &d1, float &d2, float &d3, float &d4, float &d5, float &d6, float &d7) {
float tmp0 = d0 + d7;
float tmp7 = d0 - d7;
float tmp1 = d1 + d6;
float tmp6 = d1 - d6;
float tmp2 = d2 + d5;
float tmp5 = d2 - d5;
float tmp3 = d3 + d4;
float tmp4 = d3 - d4;
// Even part
float tmp10 = tmp0 + tmp3; // phase 2
float tmp13 = tmp0 - tmp3;
float tmp11 = tmp1 + tmp2;
float tmp12 = tmp1 - tmp2;
d0 = tmp10 + tmp11; // phase 3
d4 = tmp10 - tmp11;
float z1 = (tmp12 + tmp13) * 0.707106781f; // c4
d2 = tmp13 + z1; // phase 5
d6 = tmp13 - z1;
// Odd part
tmp10 = tmp4 + tmp5; // phase 2
tmp11 = tmp5 + tmp6;
tmp12 = tmp6 + tmp7;
// The rotator is modified from fig 4-8 to avoid extra negations.
float z5 = (tmp10 - tmp12) * 0.382683433f; // c6
float z2 = tmp10 * 0.541196100f + z5; // c2-c6
float z4 = tmp12 * 1.306562965f + z5; // c2+c6
float z3 = tmp11 * 0.707106781f; // c4
float z11 = tmp7 + z3; // phase 5
float z13 = tmp7 - z3;
d5 = z13 + z2; // phase 6
d3 = z13 - z2;
d1 = z11 + z4;
d7 = z11 - z4;
}
static void jo_calcBits(int val, unsigned short bits[2]) {
int tmp1 = val < 0 ? -val : val;
val = val < 0 ? val-1 : val;
bits[1] = 1;
while(tmp1 >>= 1) {
++bits[1];
}
bits[0] = val & ((1<<bits[1])-1);
}
static int jo_processDU(FILE *fp, int &bitBuf, int &bitCnt, float *CDU, float *fdtbl, int DC, const unsigned short HTDC[256][2], const unsigned short HTAC[256][2]) {
const unsigned short EOB[2] = { HTAC[0x00][0], HTAC[0x00][1] };
const unsigned short M16zeroes[2] = { HTAC[0xF0][0], HTAC[0xF0][1] };
// DCT rows
for(int dataOff=0; dataOff<64; dataOff+=8) {
jo_DCT(CDU[dataOff], CDU[dataOff+1], CDU[dataOff+2], CDU[dataOff+3], CDU[dataOff+4], CDU[dataOff+5], CDU[dataOff+6], CDU[dataOff+7]);
}
// DCT columns
for(int dataOff=0; dataOff<8; ++dataOff) {
jo_DCT(CDU[dataOff], CDU[dataOff+8], CDU[dataOff+16], CDU[dataOff+24], CDU[dataOff+32], CDU[dataOff+40], CDU[dataOff+48], CDU[dataOff+56]);
}
// Quantize/descale/zigzag the coefficients
int DU[64];
for(int i=0; i<64; ++i) {
float v = CDU[i]*fdtbl[i];
DU[s_jo_ZigZag[i]] = (int)(v < 0 ? ceilf(v - 0.5f) : floorf(v + 0.5f));
}
// Encode DC
int diff = DU[0] - DC;
if (diff == 0) {
jo_writeBits(fp, bitBuf, bitCnt, HTDC[0]);
} else {
unsigned short bits[2];
jo_calcBits(diff, bits);
jo_writeBits(fp, bitBuf, bitCnt, HTDC[bits[1]]);
jo_writeBits(fp, bitBuf, bitCnt, bits);
}
// Encode ACs
int end0pos = 63;
for(; (end0pos>0)&&(DU[end0pos]==0); --end0pos) {
}
// end0pos = first element in reverse order !=0
if(end0pos == 0) {
jo_writeBits(fp, bitBuf, bitCnt, EOB);
return DU[0];
}
for(int i = 1; i <= end0pos; ++i) {
int startpos = i;
for (; DU[i]==0 && i<=end0pos; ++i) {
}
int nrzeroes = i-startpos;
if ( nrzeroes >= 16 ) {
int lng = nrzeroes>>4;
for (int nrmarker=1; nrmarker <= lng; ++nrmarker)
jo_writeBits(fp, bitBuf, bitCnt, M16zeroes);
nrzeroes &= 15;
}
unsigned short bits[2];
jo_calcBits(DU[i], bits);
jo_writeBits(fp, bitBuf, bitCnt, HTAC[(nrzeroes<<4)+bits[1]]);
jo_writeBits(fp, bitBuf, bitCnt, bits);
}
if(end0pos != 63) {
jo_writeBits(fp, bitBuf, bitCnt, EOB);
}
return DU[0];
}
bool jo_write_jpg(const char *filename, const void *data, int width, int height, int quality) {
// Constants that don't pollute global namespace
static const unsigned char std_dc_luminance_nrcodes[] = {0,0,1,5,1,1,1,1,1,1,0,0,0,0,0,0,0};
static const unsigned char std_dc_luminance_values[] = {0,1,2,3,4,5,6,7,8,9,10,11};
static const unsigned char std_ac_luminance_nrcodes[] = {0,0,2,1,3,3,2,4,3,5,5,4,4,0,0,1,0x7d};
static const unsigned char std_ac_luminance_values[] = {
0x01,0x02,0x03,0x00,0x04,0x11,0x05,0x12,0x21,0x31,0x41,0x06,0x13,0x51,0x61,0x07,0x22,0x71,0x14,0x32,0x81,0x91,0xa1,0x08,
0x23,0x42,0xb1,0xc1,0x15,0x52,0xd1,0xf0,0x24,0x33,0x62,0x72,0x82,0x09,0x0a,0x16,0x17,0x18,0x19,0x1a,0x25,0x26,0x27,0x28,
0x29,0x2a,0x34,0x35,0x36,0x37,0x38,0x39,0x3a,0x43,0x44,0x45,0x46,0x47,0x48,0x49,0x4a,0x53,0x54,0x55,0x56,0x57,0x58,0x59,
0x5a,0x63,0x64,0x65,0x66,0x67,0x68,0x69,0x6a,0x73,0x74,0x75,0x76,0x77,0x78,0x79,0x7a,0x83,0x84,0x85,0x86,0x87,0x88,0x89,
0x8a,0x92,0x93,0x94,0x95,0x96,0x97,0x98,0x99,0x9a,0xa2,0xa3,0xa4,0xa5,0xa6,0xa7,0xa8,0xa9,0xaa,0xb2,0xb3,0xb4,0xb5,0xb6,
0xb7,0xb8,0xb9,0xba,0xc2,0xc3,0xc4,0xc5,0xc6,0xc7,0xc8,0xc9,0xca,0xd2,0xd3,0xd4,0xd5,0xd6,0xd7,0xd8,0xd9,0xda,0xe1,0xe2,
0xe3,0xe4,0xe5,0xe6,0xe7,0xe8,0xe9,0xea,0xf1,0xf2,0xf3,0xf4,0xf5,0xf6,0xf7,0xf8,0xf9,0xfa
};
static const unsigned char std_dc_chrominance_nrcodes[] = {0,0,3,1,1,1,1,1,1,1,1,1,0,0,0,0,0};
static const unsigned char std_dc_chrominance_values[] = {0,1,2,3,4,5,6,7,8,9,10,11};
static const unsigned char std_ac_chrominance_nrcodes[] = {0,0,2,1,2,4,4,3,4,7,5,4,4,0,1,2,0x77};
static const unsigned char std_ac_chrominance_values[] = {
0x00,0x01,0x02,0x03,0x11,0x04,0x05,0x21,0x31,0x06,0x12,0x41,0x51,0x07,0x61,0x71,0x13,0x22,0x32,0x81,0x08,0x14,0x42,0x91,
0xa1,0xb1,0xc1,0x09,0x23,0x33,0x52,0xf0,0x15,0x62,0x72,0xd1,0x0a,0x16,0x24,0x34,0xe1,0x25,0xf1,0x17,0x18,0x19,0x1a,0x26,
0x27,0x28,0x29,0x2a,0x35,0x36,0x37,0x38,0x39,0x3a,0x43,0x44,0x45,0x46,0x47,0x48,0x49,0x4a,0x53,0x54,0x55,0x56,0x57,0x58,
0x59,0x5a,0x63,0x64,0x65,0x66,0x67,0x68,0x69,0x6a,0x73,0x74,0x75,0x76,0x77,0x78,0x79,0x7a,0x82,0x83,0x84,0x85,0x86,0x87,
0x88,0x89,0x8a,0x92,0x93,0x94,0x95,0x96,0x97,0x98,0x99,0x9a,0xa2,0xa3,0xa4,0xa5,0xa6,0xa7,0xa8,0xa9,0xaa,0xb2,0xb3,0xb4,
0xb5,0xb6,0xb7,0xb8,0xb9,0xba,0xc2,0xc3,0xc4,0xc5,0xc6,0xc7,0xc8,0xc9,0xca,0xd2,0xd3,0xd4,0xd5,0xd6,0xd7,0xd8,0xd9,0xda,
0xe2,0xe3,0xe4,0xe5,0xe6,0xe7,0xe8,0xe9,0xea,0xf2,0xf3,0xf4,0xf5,0xf6,0xf7,0xf8,0xf9,0xfa
};
// Huffman tables
static const unsigned short YDC_HT[256][2] = { {0,2},{2,3},{3,3},{4,3},{5,3},{6,3},{14,4},{30,5},{62,6},{126,7},{254,8},{510,9}};
static const unsigned short UVDC_HT[256][2] = { {0,2},{1,2},{2,2},{6,3},{14,4},{30,5},{62,6},{126,7},{254,8},{510,9},{1022,10},{2046,11}};
static const unsigned short YAC_HT[256][2] = {
{10,4},{0,2},{1,2},{4,3},{11,4},{26,5},{120,7},{248,8},{1014,10},{65410,16},{65411,16},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},
{12,4},{27,5},{121,7},{502,9},{2038,11},{65412,16},{65413,16},{65414,16},{65415,16},{65416,16},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},
{28,5},{249,8},{1015,10},{4084,12},{65417,16},{65418,16},{65419,16},{65420,16},{65421,16},{65422,16},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},
{58,6},{503,9},{4085,12},{65423,16},{65424,16},{65425,16},{65426,16},{65427,16},{65428,16},{65429,16},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},
{59,6},{1016,10},{65430,16},{65431,16},{65432,16},{65433,16},{65434,16},{65435,16},{65436,16},{65437,16},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},
{122,7},{2039,11},{65438,16},{65439,16},{65440,16},{65441,16},{65442,16},{65443,16},{65444,16},{65445,16},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},
{123,7},{4086,12},{65446,16},{65447,16},{65448,16},{65449,16},{65450,16},{65451,16},{65452,16},{65453,16},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},
{250,8},{4087,12},{65454,16},{65455,16},{65456,16},{65457,16},{65458,16},{65459,16},{65460,16},{65461,16},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},
{504,9},{32704,15},{65462,16},{65463,16},{65464,16},{65465,16},{65466,16},{65467,16},{65468,16},{65469,16},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},
{505,9},{65470,16},{65471,16},{65472,16},{65473,16},{65474,16},{65475,16},{65476,16},{65477,16},{65478,16},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},
{506,9},{65479,16},{65480,16},{65481,16},{65482,16},{65483,16},{65484,16},{65485,16},{65486,16},{65487,16},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},
{1017,10},{65488,16},{65489,16},{65490,16},{65491,16},{65492,16},{65493,16},{65494,16},{65495,16},{65496,16},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},
{1018,10},{65497,16},{65498,16},{65499,16},{65500,16},{65501,16},{65502,16},{65503,16},{65504,16},{65505,16},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},
{2040,11},{65506,16},{65507,16},{65508,16},{65509,16},{65510,16},{65511,16},{65512,16},{65513,16},{65514,16},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},
{65515,16},{65516,16},{65517,16},{65518,16},{65519,16},{65520,16},{65521,16},{65522,16},{65523,16},{65524,16},{0,0},{0,0},{0,0},{0,0},{0,0},
{2041,11},{65525,16},{65526,16},{65527,16},{65528,16},{65529,16},{65530,16},{65531,16},{65532,16},{65533,16},{65534,16},{0,0},{0,0},{0,0},{0,0},{0,0}
};
static const unsigned short UVAC_HT[256][2] = {
{0,2},{1,2},{4,3},{10,4},{24,5},{25,5},{56,6},{120,7},{500,9},{1014,10},{4084,12},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},
{11,4},{57,6},{246,8},{501,9},{2038,11},{4085,12},{65416,16},{65417,16},{65418,16},{65419,16},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},
{26,5},{247,8},{1015,10},{4086,12},{32706,15},{65420,16},{65421,16},{65422,16},{65423,16},{65424,16},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},
{27,5},{248,8},{1016,10},{4087,12},{65425,16},{65426,16},{65427,16},{65428,16},{65429,16},{65430,16},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},
{58,6},{502,9},{65431,16},{65432,16},{65433,16},{65434,16},{65435,16},{65436,16},{65437,16},{65438,16},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},
{59,6},{1017,10},{65439,16},{65440,16},{65441,16},{65442,16},{65443,16},{65444,16},{65445,16},{65446,16},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},
{121,7},{2039,11},{65447,16},{65448,16},{65449,16},{65450,16},{65451,16},{65452,16},{65453,16},{65454,16},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},
{122,7},{2040,11},{65455,16},{65456,16},{65457,16},{65458,16},{65459,16},{65460,16},{65461,16},{65462,16},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},
{249,8},{65463,16},{65464,16},{65465,16},{65466,16},{65467,16},{65468,16},{65469,16},{65470,16},{65471,16},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},
{503,9},{65472,16},{65473,16},{65474,16},{65475,16},{65476,16},{65477,16},{65478,16},{65479,16},{65480,16},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},
{504,9},{65481,16},{65482,16},{65483,16},{65484,16},{65485,16},{65486,16},{65487,16},{65488,16},{65489,16},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},
{505,9},{65490,16},{65491,16},{65492,16},{65493,16},{65494,16},{65495,16},{65496,16},{65497,16},{65498,16},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},
{506,9},{65499,16},{65500,16},{65501,16},{65502,16},{65503,16},{65504,16},{65505,16},{65506,16},{65507,16},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},
{2041,11},{65508,16},{65509,16},{65510,16},{65511,16},{65512,16},{65513,16},{65514,16},{65515,16},{65516,16},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},
{16352,14},{65517,16},{65518,16},{65519,16},{65520,16},{65521,16},{65522,16},{65523,16},{65524,16},{65525,16},{0,0},{0,0},{0,0},{0,0},{0,0},
{1018,10},{32707,15},{65526,16},{65527,16},{65528,16},{65529,16},{65530,16},{65531,16},{65532,16},{65533,16},{65534,16},{0,0},{0,0},{0,0},{0,0},{0,0}
};
static const int YQT[] = {16,11,10,16,24,40,51,61,12,12,14,19,26,58,60,55,14,13,16,24,40,57,69,56,14,17,22,29,51,87,80,62,18,22,37,56,68,109,103,77,24,35,55,64,81,104,113,92,49,64,78,87,103,121,120,101,72,92,95,98,112,100,103,99};
static const int UVQT[] = {17,18,24,47,99,99,99,99,18,21,26,66,99,99,99,99,24,26,56,99,99,99,99,99,47,66,99,99,99,99,99,99,99,99,99,99,99,99,99,99,99,99,99,99,99,99,99,99,99,99,99,99,99,99,99,99,99,99,99,99,99,99,99,99};
static const float aasf[] = { 1.0 * 2.828427125, 1.387039845 * 2.828427125, 1.306562965 * 2.828427125, 1.175875602 * 2.828427125, 1.0 * 2.828427125, 0.785694958 * 2.828427125, 0.541196100 * 2.828427125, 0.275899379 * 2.828427125 };
if(!data || !filename || !width || !height) {
return false;
}
FILE *fp = fopen(filename, "wb");
if(!fp) {
return false;
}
quality = quality ? quality : 90;
quality = quality < 1 ? 1 : quality > 100 ? 100 : quality;
quality = quality < 50 ? 5000 / quality : 200 - quality * 2;
unsigned char YTable[64], UVTable[64];
for(int i = 0; i < 64; ++i) {
int yti = (YQT[i]*quality+50)/100;
YTable[s_jo_ZigZag[i]] = yti < 1 ? 1 : yti > 255 ? 255 : yti;
int uvti = (UVQT[i]*quality+50)/100;
UVTable[s_jo_ZigZag[i]] = uvti < 1 ? 1 : uvti > 255 ? 255 : uvti;
}
float fdtbl_Y[64], fdtbl_UV[64];
for(int row = 0, k = 0; row < 8; ++row) {
for(int col = 0; col < 8; ++col, ++k) {
fdtbl_Y[k] = 1 / (YTable [s_jo_ZigZag[k]] * aasf[row] * aasf[col]);
fdtbl_UV[k] = 1 / (UVTable[s_jo_ZigZag[k]] * aasf[row] * aasf[col]);
}
}
// Write Headers
static const unsigned char head0[] = { 0xFF,0xD8,0xFF,0xE0,0,0x10,'J','F','I','F',0,1,1,0,0,1,0,1,0,0,0xFF,0xDB,0,0x84,0 };
fwrite(head0, sizeof(head0), 1, fp);
fwrite(YTable, sizeof(YTable), 1, fp);
putc(1, fp);
fwrite(UVTable, sizeof(UVTable), 1, fp);
const unsigned char head1[] = { 0xFF,0xC0,0,0x11,8,height>>8,height&0xFF,width>>8,width&0xFF,3,1,0x11,0,2,0x11,1,3,0x11,1,0xFF,0xC4,0x01,0xA2,0 };
fwrite(head1, sizeof(head1), 1, fp);
fwrite(std_dc_luminance_nrcodes+1, sizeof(std_dc_luminance_nrcodes)-1, 1, fp);
fwrite(std_dc_luminance_values, sizeof(std_dc_luminance_values), 1, fp);
putc(0x10, fp); // HTYACinfo
fwrite(std_ac_luminance_nrcodes+1, sizeof(std_ac_luminance_nrcodes)-1, 1, fp);
fwrite(std_ac_luminance_values, sizeof(std_ac_luminance_values), 1, fp);
putc(1, fp); // HTUDCinfo
fwrite(std_dc_chrominance_nrcodes+1, sizeof(std_dc_chrominance_nrcodes)-1, 1, fp);
fwrite(std_dc_chrominance_values, sizeof(std_dc_chrominance_values), 1, fp);
putc(0x11, fp); // HTUACinfo
fwrite(std_ac_chrominance_nrcodes+1, sizeof(std_ac_chrominance_nrcodes)-1, 1, fp);
fwrite(std_ac_chrominance_values, sizeof(std_ac_chrominance_values), 1, fp);
static const unsigned char head2[] = { 0xFF,0xDA,0,0xC,3,1,0,2,0x11,3,0x11,0,0x3F,0 };
fwrite(head2, sizeof(head2), 1, fp);
// Encode 8x8 macroblocks
const unsigned char *imageData = (const unsigned char *)data;
int DCY=0, DCU=0, DCV=0;
int bitBuf=0, bitCnt=0;
for(int y = 0; y < height; y += 8) {
for(int x = 0; x < width; x += 8) {
float YDU[64], UDU[64], VDU[64];
for(int row = y, pos = 0; row < y+8; ++row) {
for(int col = x; col < x+8; ++col, ++pos) {
int p = row*width*4 + col*4;
if(row >= height) {
p -= width*4*(row+1 - height);
}
if(col >= width) {
p -= 4*(col+1 - width);
}
float r = imageData[p+0], g = imageData[p+1], b = imageData[p+2];
YDU[pos]=+0.29900*r+0.58700*g+0.11400*b-128;
UDU[pos]=-0.16874*r-0.33126*g+0.50000*b;
VDU[pos]=+0.50000*r-0.41869*g-0.08131*b;
}
}
DCY = jo_processDU(fp, bitBuf, bitCnt, YDU, fdtbl_Y, DCY, YDC_HT, YAC_HT);
DCU = jo_processDU(fp, bitBuf, bitCnt, UDU, fdtbl_UV, DCU, UVDC_HT, UVAC_HT);
DCV = jo_processDU(fp, bitBuf, bitCnt, VDU, fdtbl_UV, DCV, UVDC_HT, UVAC_HT);
}
}
// Do the bit alignment of the EOI marker
static const unsigned short fillBits[] = {0x7F, 7};
jo_writeBits(fp, bitBuf, bitCnt, fillBits);
// EOI
putc(0xFF, fp);
putc(0xD9, fp);
fclose(fp);
return true;
}
#endif