那些年啊，那些事---V4L2采集图片源码分享

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那些年啊，那些事---V4L2采集图片源码分享

把v4l2采集图片测试程序，贴在这和大家共享，在此基础上可以使实现视频的采集，只不过在pc机上写个上位机进行显示或者直接写个Qt在开发板上显示即可，


源码如下：

1. [cpp] view plaincopyprint?
   
2. #include <stdio.h>   
   
3. #include <stdlib.h>   
   
4. #include <string.h>   
   
5. #include <assert.h>   
   
6.   
   
7. #include <getopt.h>   
   
8.   
   
9. #include <fcntl.h>   
   
10. #include <unistd.h>   
    
11. #include <errno.h>   
    
12. #include <malloc.h>   
    
13. #include <sys/stat.h>   
    
14. #include <sys/types.h>   
    
15. #include <sys/time.h>   
    
16. #include <sys/mman.h>   
    
17. #include <sys/ioctl.h>   
    
18.   
    
19. #include <asm/types.h>   
    
20. #include <linux/videodev2.h>   
    
21.   
    
22. #define CLEAR(x) memset (&(x), 0, sizeof (x))   
    
23.   
    
24. struct buffer {  
    
25. void * start;  
    
26. size_t length;  
    
27. };  
    
28.   
    
29. static char * dev_name = "/dev/video0";  
    
30. static int fd = -1;  
    
31. struct buffer * buffers = NULL;  
    
32.   
    
33. FILE *file_fd;  
    
34. static unsigned long file_length;  
    
35. static unsigned char *file_name;  
    
36.   
    
37. int main (int argc,char ** argv)  
    
38. {  
    
39. struct v4l2_capability cap;  
    
40. struct v4l2_format fmt;  
    
41.   
    
42. file_fd = fopen("test.jpg", "w");  
    
43.   
    
44. fd = open (dev_name, O_RDWR /* required */ | O_NONBLOCK, 0);  
    
45.   
    
46. ioctl (fd, VIDIOC_QUERYCAP, &cap);  
    
47.   
    
48. CLEAR (fmt);  
    
49. fmt.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;  
    
50. fmt.fmt.pix.width = 640;  
    
51. fmt.fmt.pix.height = 480;  
    
52. fmt.fmt.pix.pixelformat = V4L2_PIX_FMT_YUYV;  
    
53. fmt.fmt.pix.field = V4L2_FIELD_INTERLACED;  
    
54. ioctl (fd, VIDIOC_S_FMT, &fmt);  
    
55.   
    
56. file_length = fmt.fmt.pix.bytesperline * fmt.fmt.pix.height;  
    
57.   
    
58. buffers = calloc (1, sizeof (*buffers));  
    
59.   
    
60. buffers[0].length = file_length;  
    
61. buffers[0].start = malloc (file_length);  
    
62.   
    
63. for (;;)  
    
64. {  
    
65. fd_set fds;  
    
66. struct timeval tv;  
    
67. int r;  
    
68.   
    
69. FD_ZERO (&fds);  
    
70. FD_SET (fd, &fds);  
    
71.   
    
72. /* Timeout. */  
    
73. tv.tv_sec = 3;  
    
74. tv.tv_usec = 0;  
    
75.   
    
76. r = select (fd + 1, &fds, NULL, NULL, &tv);  
    
77.   
    
78. if (-1 == r) {  
    
79. if (EINTR == errno)  
    
80. continue;  
    
81. printf ("select");  
    
82. }  
    
83.   
    
84. if (0 == r) {  
    
85. fprintf (stderr, "select timeout\n");  
    
86. exit (EXIT_FAILURE);  
    
87. }  
    
88.   
    
89. if (read (fd, buffers[0].start, buffers[0].length))  
    
90. break;  
    
91. }  
    
92.   
    
93. fwrite(buffers[0].start, buffers[0].length, 1, file_fd);  
    
94.   
    
95. free (buffers[0].start);  
    
96. close (fd);  
    
97. fclose (file_fd);  
    
98. exit (EXIT_SUCCESS);  
    
99. return 0;  
    
100. }  
     
101. #include <stdio.h>
     
102. #include <stdlib.h>
     
103. #include <string.h>
     
104. #include <assert.h>
     
105. 
     
106. #include <getopt.h>
     
107. 
     
108. #include <fcntl.h>
     
109. #include <unistd.h>
     
110. #include <errno.h>
     
111. #include <malloc.h>
     
112. #include <sys/stat.h>
     
113. #include <sys/types.h>
     
114. #include <sys/time.h>
     
115. #include <sys/mman.h>
     
116. #include <sys/ioctl.h>
     
117. 
     
118. #include <asm/types.h>
     
119. #include <linux/videodev2.h>
     
120. 
     
121. #define CLEAR(x) memset (&(x), 0, sizeof (x))
     
122. 
     
123. struct buffer {
     
124. void * start;
     
125. size_t length;
     
126. };
     
127. 
     
128. static char * dev_name = "/dev/video0";
     
129. static int fd = -1;
     
130. struct buffer * buffers = NULL;
     
131. 
     
132. FILE *file_fd;
     
133. static unsigned long file_length;
     
134. static unsigned char *file_name;
     
135. 
     
136. int main (int argc,char ** argv)
     
137. {
     
138. struct v4l2_capability cap;
     
139. struct v4l2_format fmt;
     
140. 
     
141. file_fd = fopen("test.jpg", "w");
     
142. 
     
143. fd = open (dev_name, O_RDWR /* required */ | O_NONBLOCK, 0);
     
144. 
     
145. ioctl (fd, VIDIOC_QUERYCAP, &cap);
     
146. 
     
147. CLEAR (fmt);
     
148. fmt.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
     
149. fmt.fmt.pix.width = 640;
     
150. fmt.fmt.pix.height = 480;
     
151. fmt.fmt.pix.pixelformat = V4L2_PIX_FMT_YUYV;
     
152. fmt.fmt.pix.field = V4L2_FIELD_INTERLACED;
     
153. ioctl (fd, VIDIOC_S_FMT, &fmt);
     
154. 
     
155. file_length = fmt.fmt.pix.bytesperline * fmt.fmt.pix.height;
     
156. 
     
157. buffers = calloc (1, sizeof (*buffers));
     
158. 
     
159. buffers[0].length = file_length;
     
160. buffers[0].start = malloc (file_length);
     
161. 
     
162. for (;;)
     
163. {
     
164. fd_set fds;
     
165. struct timeval tv;
     
166. int r;
     
167. 
     
168. FD_ZERO (&fds);
     
169. FD_SET (fd, &fds);
     
170. 
     
171. /* Timeout. */
     
172. tv.tv_sec = 3;
     
173. tv.tv_usec = 0;
     
174. 
     
175. r = select (fd + 1, &fds, NULL, NULL, &tv);
     
176. 
     
177. if (-1 == r) {
     
178. if (EINTR == errno)
     
179. continue;
     
180. printf ("select");
     
181. }
     
182. 
     
183. if (0 == r) {
     
184. fprintf (stderr, "select timeout\n");
     
185. exit (EXIT_FAILURE);
     
186. }
     
187. 
     
188. if (read (fd, buffers[0].start, buffers[0].length))
     
189. break;
     
190. }
     
191. 
     
192. fwrite(buffers[0].start, buffers[0].length, 1, file_fd);
     
193. 
     
194. free (buffers[0].start);
     
195. close (fd);
     
196. fclose (file_fd);
     
197. exit (EXIT_SUCCESS);
     
198. return 0;
     
199. }

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星期六的深夜68

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