1 /* readyuv.c - read an Abekas A66 style image file. Steve Simon, 2003 */
2 #include <u.h>
3 #include <libc.h>
4 #include <bio.h>
5 #include <draw.h>
6 #include <ctype.h>
7 #include "imagefile.h"
8
9
10 enum {
11 Pixels = 720,
12 R601pal = 576,
13 R601ntsc = 486,
14 Shift = 13
15 };
16
17
18 static int lsbtab[] = { 6, 4, 2, 0};
19
20 static int
looksize(char * file,vlong size,int * pixels,int * lines,int * bits)21 looksize(char *file, vlong size, int *pixels, int *lines, int *bits)
22 {
23 Biobuf *bp;
24 uvlong l, p;
25 char *s, *a[12];
26
27 /*
28 * This may not always work, there could be an alias between file
29 * sizes of different standards stored in 8bits and 10 bits.
30 */
31 if ((bp = Bopen(file, OREAD)) == nil)
32 return -1;
33 while((s = Brdstr(bp, '\n', 1)) != nil){
34 if (tokenize(s, a, nelem(a)) < 3)
35 continue;
36 if (a[0][0] == '#')
37 continue;
38 p = atoll(a[3]);
39 l = atoll(a[5]);
40 l += atoll(a[7]);
41 if (l*p*2 == size){
42 *pixels = p;
43 *lines = l;
44 *bits = 8;
45 break;
46 }
47 if ((l*p*20)/8 == size){
48 *pixels = p;
49 *lines = l;
50 *bits = 10;
51 break;
52 }
53 }
54 Bterm(bp);
55 if (s == nil)
56 return -1;
57 return 0;
58 }
59
60
61 static int
clip(int x)62 clip(int x)
63 {
64 x >>= (Shift+2); // +2 as we assume all input images are 10 bit
65
66 if (x > 255)
67 return 0xff;
68 if (x <= 0)
69 return 0;
70 return x;
71 }
72
73 Rawimage**
Breadyuv(Biobuf * bp,int colourspace)74 Breadyuv(Biobuf *bp, int colourspace)
75 {
76 Dir *d;
77 uvlong sz;
78 Rawimage *a, **array;
79 ushort * mux, *end, *frm;
80 uchar *buf, *r, *g, *b;
81 int y1, y2, cb, cr, c, l, w, base;
82 int bits, lines, pixels;
83 int F1, F2, F3, F4;
84
85 if ((d = dirfstat(Bfildes(bp))) != nil){
86 sz = d->length;
87 free(d);
88 }
89 else{
90 fprint(2, "cannot stat input, assuming pixelsx576x10bit\n");
91 sz = Pixels * R601pal * 2L + (Pixels * R601pal / 2L);
92 }
93
94 if (looksize("/lib/video.specs", sz, &pixels, &lines, &bits) == -1){
95 werrstr("file size not listed in /lib/video.specs");
96 return nil;
97 }
98
99 buf = nil;
100 if (colourspace != CYCbCr) {
101 werrstr("ReadYUV: unknown colour space %d", colourspace);
102 return nil;
103 }
104
105 if ((a = calloc(sizeof(Rawimage), 1)) == nil)
106 sysfatal("no memory");
107
108 if ((array = calloc(sizeof(Rawimage * ), 2)) == nil)
109 sysfatal("no memory");
110 array[0] = a;
111 array[1] = nil;
112
113 a->nchans = 3;
114 a->chandesc = CRGB;
115 a->chanlen = pixels * lines;
116 a->r = Rect(0, 0, pixels, lines);
117
118 if ((frm = malloc(pixels*2*lines*sizeof(ushort))) == nil)
119 goto Error;
120
121 for (c = 0; c < 3; c++)
122 if ((a->chans[c] = malloc(pixels*lines)) == nil)
123 goto Error;
124
125 if ((buf = malloc(pixels*2)) == nil)
126 goto Error;
127
128 for (l = 0; l < lines; l++) {
129 if (Bread(bp, buf, pixels *2) == -1)
130 goto Error;
131
132 base = l*pixels*2;
133 for (w = 0; w < pixels *2; w++)
134 frm[base + w] = ((ushort)buf[w]) << 2;
135 }
136
137
138 if (bits == 10)
139 for (l = 0; l < lines; l++) {
140 if (Bread(bp, buf, pixels / 2) == -1)
141 goto Error;
142
143
144 base = l * pixels * 2;
145 for (w = 0; w < pixels * 2; w++)
146 frm[base + w] |= (buf[w / 4] >> lsbtab[w % 4]) & 3;
147 }
148
149 mux = frm;
150 end = frm + pixels * lines * 2;
151 r = a->chans[0];
152 g = a->chans[1];
153 b = a->chans[2];
154
155 if(pixels == Pixels && lines != R601pal){ // 625
156 F1 = floor(1.402 * (1 << Shift));
157 F2 = floor(0.34414 * (1 << Shift));
158 F3 = floor(0.71414 * (1 << Shift));
159 F4 = floor(1.772 * (1 << Shift));
160 }
161 else{ // 525
162 F1 = floor(1.5748 * (1 << Shift));
163 F2 = floor(0.1874 * (1 << Shift));
164 F3 = floor(0.4681 * (1 << Shift));
165 F4 = floor(1.8560 * (1 << Shift));
166 }
167
168 /*
169 * Fixme: fixed colourspace conversion at present
170 */
171 while (mux < end) {
172
173 cb = *mux++ - 512;
174 y1 = (int)*mux++ << Shift;
175 cr = *mux++ - 512;
176 y2 = (int)*mux++ << Shift;
177
178 *r++ = clip(y1 + F1*cr);
179 *g++ = clip(y1 - F2*cb - F3*cr);
180 *b++ = clip((y1 + F4*cb));
181
182 *r++ = clip(y2 + F1*cr);
183 *g++ = clip(y2 - F2*cb - F3*cr);
184 *b++ = clip((y2 + F4*cb));
185 }
186 free(frm);
187 free(buf);
188 return array;
189
190 Error:
191 for (c = 0; c < 3; c++)
192 free(a->chans[c]);
193 free(a->cmap);
194 free(array[0]);
195 free(array);
196 free(frm);
197 free(buf);
198 return nil;
199 }
200
201
202 Rawimage**
readyuv(int fd,int colorspace)203 readyuv(int fd, int colorspace)
204 {
205 Rawimage * *a;
206 Biobuf b;
207
208 if (Binit(&b, fd, OREAD) < 0)
209 return nil;
210 a = Breadyuv(&b, colorspace);
211 Bterm(&b);
212 return a;
213 }
214
215
216