Linux Kernel  3.7.1
 All Data Structures Namespaces Files Functions Variables Typedefs Enumerations Enumerator Macros Groups Pages
jpeg.h
Go to the documentation of this file.
1 #ifndef JPEG_H
2 #define JPEG_H 1
3 /*
4  * Insert a JPEG header at start of frame
5  *
6  * This module is used by the gspca subdrivers.
7  * A special case is done for Conexant webcams.
8  *
9  * Copyright (C) Jean-Francois Moine (http://moinejf.free.fr)
10  *
11  * This program is free software; you can redistribute it and/or modify
12  * it under the terms of the GNU General Public License as published by
13  * the Free Software Foundation; either version 2 of the License, or
14  * any later version.
15  *
16  * This program is distributed in the hope that it will be useful,
17  * but WITHOUT ANY WARRANTY; without even the implied warranty of
18  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
19  * GNU General Public License for more details.
20  *
21  * You should have received a copy of the GNU General Public License
22  * along with this program; if not, write to the Free Software
23  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
24  *
25  */
26 
27 /*
28  * generation options
29  * CONEX_CAM Conexant if present
30  */
31 
32 /* JPEG header */
33 static const u8 jpeg_head[] = {
34  0xff, 0xd8, /* jpeg */
35 
36 /* quantization table quality 50% */
37  0xff, 0xdb, 0x00, 0x84, /* DQT */
38 0,
39 #define JPEG_QT0_OFFSET 7
40  0x10, 0x0b, 0x0c, 0x0e, 0x0c, 0x0a, 0x10, 0x0e,
41  0x0d, 0x0e, 0x12, 0x11, 0x10, 0x13, 0x18, 0x28,
42  0x1a, 0x18, 0x16, 0x16, 0x18, 0x31, 0x23, 0x25,
43  0x1d, 0x28, 0x3a, 0x33, 0x3d, 0x3c, 0x39, 0x33,
44  0x38, 0x37, 0x40, 0x48, 0x5c, 0x4e, 0x40, 0x44,
45  0x57, 0x45, 0x37, 0x38, 0x50, 0x6d, 0x51, 0x57,
46  0x5f, 0x62, 0x67, 0x68, 0x67, 0x3e, 0x4d, 0x71,
47  0x79, 0x70, 0x64, 0x78, 0x5c, 0x65, 0x67, 0x63,
48 1,
49 #define JPEG_QT1_OFFSET 72
50  0x11, 0x12, 0x12, 0x18, 0x15, 0x18, 0x2f, 0x1a,
51  0x1a, 0x2f, 0x63, 0x42, 0x38, 0x42, 0x63, 0x63,
52  0x63, 0x63, 0x63, 0x63, 0x63, 0x63, 0x63, 0x63,
53  0x63, 0x63, 0x63, 0x63, 0x63, 0x63, 0x63, 0x63,
54  0x63, 0x63, 0x63, 0x63, 0x63, 0x63, 0x63, 0x63,
55  0x63, 0x63, 0x63, 0x63, 0x63, 0x63, 0x63, 0x63,
56  0x63, 0x63, 0x63, 0x63, 0x63, 0x63, 0x63, 0x63,
57  0x63, 0x63, 0x63, 0x63, 0x63, 0x63, 0x63, 0x63,
58 
59 /* huffman table */
60  0xff, 0xc4, 0x01, 0xa2,
61  0x00, 0x00, 0x01, 0x05, 0x01, 0x01, 0x01, 0x01,
62  0x01, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
63  0x00, 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06,
64  0x07, 0x08, 0x09, 0x0a, 0x0b, 0x01, 0x00, 0x03,
65  0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01,
66  0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01,
67  0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09,
68  0x0a, 0x0b, 0x10, 0x00, 0x02, 0x01, 0x03, 0x03,
69  0x02, 0x04, 0x03, 0x05, 0x05, 0x04, 0x04, 0x00,
70  0x00, 0x01, 0x7d, 0x01, 0x02, 0x03, 0x00, 0x04,
71  0x11, 0x05, 0x12, 0x21, 0x31, 0x41, 0x06, 0x13,
72  0x51, 0x61, 0x07, 0x22, 0x71, 0x14, 0x32, 0x81,
73  0x91, 0xa1, 0x08, 0x23, 0x42, 0xb1, 0xc1, 0x15,
74  0x52, 0xd1, 0xf0, 0x24, 0x33, 0x62, 0x72, 0x82,
75  0x09, 0x0a, 0x16, 0x17, 0x18, 0x19, 0x1a, 0x25,
76  0x26, 0x27, 0x28, 0x29, 0x2a, 0x34, 0x35, 0x36,
77  0x37, 0x38, 0x39, 0x3a, 0x43, 0x44, 0x45, 0x46,
78  0x47, 0x48, 0x49, 0x4a, 0x53, 0x54, 0x55, 0x56,
79  0x57, 0x58, 0x59, 0x5a, 0x63, 0x64, 0x65, 0x66,
80  0x67, 0x68, 0x69, 0x6a, 0x73, 0x74, 0x75, 0x76,
81  0x77, 0x78, 0x79, 0x7a, 0x83, 0x84, 0x85, 0x86,
82  0x87, 0x88, 0x89, 0x8a, 0x92, 0x93, 0x94, 0x95,
83  0x96, 0x97, 0x98, 0x99, 0x9a, 0xa2, 0xa3, 0xa4,
84  0xa5, 0xa6, 0xa7, 0xa8, 0xa9, 0xaa, 0xb2, 0xb3,
85  0xb4, 0xb5, 0xb6, 0xb7, 0xb8, 0xb9, 0xba, 0xc2,
86  0xc3, 0xc4, 0xc5, 0xc6, 0xc7, 0xc8, 0xc9, 0xca,
87  0xd2, 0xd3, 0xd4, 0xd5, 0xd6, 0xd7, 0xd8, 0xd9,
88  0xda, 0xe1, 0xe2, 0xe3, 0xe4, 0xe5, 0xe6, 0xe7,
89  0xe8, 0xe9, 0xea, 0xf1, 0xf2, 0xf3, 0xf4, 0xf5,
90  0xf6, 0xf7, 0xf8, 0xf9, 0xfa, 0x11, 0x00, 0x02,
91  0x01, 0x02, 0x04, 0x04, 0x03, 0x04, 0x07, 0x05,
92  0x04, 0x04, 0x00, 0x01, 0x02, 0x77, 0x00, 0x01,
93  0x02, 0x03, 0x11, 0x04, 0x05, 0x21, 0x31, 0x06,
94  0x12, 0x41, 0x51, 0x07, 0x61, 0x71, 0x13, 0x22,
95  0x32, 0x81, 0x08, 0x14, 0x42, 0x91, 0xa1, 0xb1,
96  0xc1, 0x09, 0x23, 0x33, 0x52, 0xf0, 0x15, 0x62,
97  0x72, 0xd1, 0x0a, 0x16, 0x24, 0x34, 0xe1, 0x25,
98  0xf1, 0x17, 0x18, 0x19, 0x1a, 0x26, 0x27, 0x28,
99  0x29, 0x2a, 0x35, 0x36, 0x37, 0x38, 0x39, 0x3a,
100  0x43, 0x44, 0x45, 0x46, 0x47, 0x48, 0x49, 0x4a,
101  0x53, 0x54, 0x55, 0x56, 0x57, 0x58, 0x59, 0x5a,
102  0x63, 0x64, 0x65, 0x66, 0x67, 0x68, 0x69, 0x6a,
103  0x73, 0x74, 0x75, 0x76, 0x77, 0x78, 0x79, 0x7a,
104  0x82, 0x83, 0x84, 0x85, 0x86, 0x87, 0x88, 0x89,
105  0x8a, 0x92, 0x93, 0x94, 0x95, 0x96, 0x97, 0x98,
106  0x99, 0x9a, 0xa2, 0xa3, 0xa4, 0xa5, 0xa6, 0xa7,
107  0xa8, 0xa9, 0xaa, 0xb2, 0xb3, 0xb4, 0xb5, 0xb6,
108  0xb7, 0xb8, 0xb9, 0xba, 0xc2, 0xc3, 0xc4, 0xc5,
109  0xc6, 0xc7, 0xc8, 0xc9, 0xca, 0xd2, 0xd3, 0xd4,
110  0xd5, 0xd6, 0xd7, 0xd8, 0xd9, 0xda, 0xe2, 0xe3,
111  0xe4, 0xe5, 0xe6, 0xe7, 0xe8, 0xe9, 0xea, 0xf2,
112  0xf3, 0xf4, 0xf5, 0xf6, 0xf7, 0xf8, 0xf9, 0xfa,
113 #ifdef CONEX_CAM
114 /* the Conexant frames start with SOF0 */
115 #define JPEG_HDR_SZ 556
116 #else
117  0xff, 0xc0, 0x00, 0x11, /* SOF0 (start of frame 0 */
118  0x08, /* data precision */
119 #define JPEG_HEIGHT_OFFSET 561
120  0x01, 0xe0, /* height */
121  0x02, 0x80, /* width */
122  0x03, /* component number */
123  0x01,
124  0x21, /* samples Y */
125  0x00, /* quant Y */
126  0x02, 0x11, 0x01, /* samples CbCr - quant CbCr */
127  0x03, 0x11, 0x01,
128 
129  0xff, 0xda, 0x00, 0x0c, /* SOS (start of scan) */
130  0x03, 0x01, 0x00, 0x02, 0x11, 0x03, 0x11, 0x00, 0x3f, 0x00
131 #define JPEG_HDR_SZ 589
132 #endif
133 };
134 
135 /* define the JPEG header */
136 static void jpeg_define(u8 *jpeg_hdr,
137  int height,
138  int width,
139  int samplesY)
140 {
141  memcpy(jpeg_hdr, jpeg_head, sizeof jpeg_head);
142 #ifndef CONEX_CAM
143  jpeg_hdr[JPEG_HEIGHT_OFFSET + 0] = height >> 8;
144  jpeg_hdr[JPEG_HEIGHT_OFFSET + 1] = height;
145  jpeg_hdr[JPEG_HEIGHT_OFFSET + 2] = width >> 8;
146  jpeg_hdr[JPEG_HEIGHT_OFFSET + 3] = width;
147  jpeg_hdr[JPEG_HEIGHT_OFFSET + 6] = samplesY;
148 #endif
149 }
150 
151 /* set the JPEG quality */
152 static void jpeg_set_qual(u8 *jpeg_hdr,
153  int quality)
154 {
155  int i, sc;
156 
157  if (quality < 50)
158  sc = 5000 / quality;
159  else
160  sc = 200 - quality * 2;
161  for (i = 0; i < 64; i++) {
162  jpeg_hdr[JPEG_QT0_OFFSET + i] =
163  (jpeg_head[JPEG_QT0_OFFSET + i] * sc + 50) / 100;
164  jpeg_hdr[JPEG_QT1_OFFSET + i] =
165  (jpeg_head[JPEG_QT1_OFFSET + i] * sc + 50) / 100;
166  }
167 }
168 #endif