pin_control: implement v4l2 capture
This commit is contained in:
Alejandro Soto
parent
e8178f0a54
commit
14766561af
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@ -4,7 +4,7 @@ project(PinControl)
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find_package(PkgConfig REQUIRED)
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pkg_check_modules(LIBGPIOD REQUIRED libgpiod)
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add_library(pin_control SHARED src/pin_control.c)
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add_library(pin_control SHARED src/pin_control.c src/v4l2.c)
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target_include_directories(pin_control PUBLIC include/ PRIVATE ${LIBGPIOD_INCLUDE_DIRS})
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target_link_libraries(pin_control PUBLIC ${LIBGPIOD_LIBRARIES})
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@ -13,4 +13,4 @@ set_target_properties(pin_control PROPERTIES POSITION_INDEPENDENT_CODE ON)
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target_compile_options(pin_control PUBLIC -Wall -Wextra -Werror)
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install(TARGETS pin_control LIBRARY DESTINATION ${CMAKE_INSTALL_LIBDIR})
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install(FILES include/pin_control.h DESTINATION ${CMAKE_INSTALL_INCLUDEDIR})
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install(FILES include/pin_control.h DESTINATION ${CMAKE_INSTALL_INCLUDEDIR})
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@ -2,19 +2,15 @@
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#define GPIO_CONTROL_H
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int init_gpio();
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void cleanup_gpio();
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int turn_on_pin(int pin);
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int turn_off_pin(int pin);
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int probe_pin(int pin);
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int turn_on_all_pins();
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int turn_off_all_pins();
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int wait_for_button_press(const unsigned pins[static 5]);
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int capture_image(const char *out);
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#endif /* GPIO_CONTROL_H */
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226
pin_control/src/v4l2.c
Normal file
226
pin_control/src/v4l2.c
Normal file
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@ -0,0 +1,226 @@
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// Derivado de https://gist.github.com/jayrambhia/5866483
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#include <errno.h>
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#include <fcntl.h>
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#include <stdint.h>
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#include <stdio.h>
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#include <string.h>
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#include <sys/ioctl.h>
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#include <sys/mman.h>
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#include <unistd.h>
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#include <linux/videodev2.h>
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#include <pin_control.h>
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static int xioctl(int fd, int request, void *arg)
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{
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int r;
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do r = ioctl (fd, request, arg);
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while (-1 == r && EINTR == errno);
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return r;
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}
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static int print_caps(int fd)
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{
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struct v4l2_capability caps = {};
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if (-1 == xioctl(fd, VIDIOC_QUERYCAP, &caps))
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{
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perror("Querying Capabilities");
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return 1;
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}
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printf( "Driver Caps:\n"
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" Driver: \"%s\"\n"
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" Card: \"%s\"\n"
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" Bus: \"%s\"\n"
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" Version: %d.%d\n"
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" Capabilities: %08x\n",
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caps.driver,
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caps.card,
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caps.bus_info,
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(caps.version>>16)&&0xff,
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(caps.version>>24)&&0xff,
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caps.capabilities);
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struct v4l2_cropcap cropcap = {0};
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cropcap.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
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if (-1 == xioctl (fd, VIDIOC_CROPCAP, &cropcap))
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{
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perror("Querying Cropping Capabilities");
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return 1;
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}
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printf( "Camera Cropping:\n"
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" Bounds: %dx%d+%d+%d\n"
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" Default: %dx%d+%d+%d\n"
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" Aspect: %d/%d\n",
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cropcap.bounds.width, cropcap.bounds.height, cropcap.bounds.left, cropcap.bounds.top,
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cropcap.defrect.width, cropcap.defrect.height, cropcap.defrect.left, cropcap.defrect.top,
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cropcap.pixelaspect.numerator, cropcap.pixelaspect.denominator);
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struct v4l2_fmtdesc fmtdesc = {0};
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fmtdesc.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
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char fourcc[5] = {0};
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char c, e;
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printf(" FMT : CE Desc\n--------------------\n");
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while (0 == xioctl(fd, VIDIOC_ENUM_FMT, &fmtdesc))
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{
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strncpy(fourcc, (char *)&fmtdesc.pixelformat, 4);
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c = fmtdesc.flags & 1? 'C' : ' ';
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e = fmtdesc.flags & 2? 'E' : ' ';
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printf(" %s: %c%c %s\n", fourcc, c, e, fmtdesc.description);
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fmtdesc.index++;
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}
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struct v4l2_format fmt = {0};
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fmt.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
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fmt.fmt.pix.width = 640;
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fmt.fmt.pix.height = 480;
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//fmt.fmt.pix.pixelformat = V4L2_PIX_FMT_BGR24;
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//fmt.fmt.pix.pixelformat = V4L2_PIX_FMT_GREY;
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fmt.fmt.pix.pixelformat = V4L2_PIX_FMT_MJPEG;
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fmt.fmt.pix.field = V4L2_FIELD_NONE;
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if (-1 == xioctl(fd, VIDIOC_S_FMT, &fmt))
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{
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perror("Setting Pixel Format");
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return 1;
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}
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strncpy(fourcc, (char *)&fmt.fmt.pix.pixelformat, 4);
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printf( "Selected Camera Mode:\n"
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" Width: %d\n"
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" Height: %d\n"
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" PixFmt: %s\n"
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" Field: %d\n",
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fmt.fmt.pix.width,
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fmt.fmt.pix.height,
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fourcc,
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fmt.fmt.pix.field);
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return 0;
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}
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static int init_mmap(int fd, uint8_t **buffer, size_t *buffer_len)
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{
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struct v4l2_requestbuffers req = {0};
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req.count = 1;
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req.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
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req.memory = V4L2_MEMORY_MMAP;
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if (-1 == xioctl(fd, VIDIOC_REQBUFS, &req))
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{
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perror("Requesting Buffer");
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return 1;
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}
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struct v4l2_buffer buf = {0};
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buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
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buf.memory = V4L2_MEMORY_MMAP;
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buf.index = 0;
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if(-1 == xioctl(fd, VIDIOC_QUERYBUF, &buf))
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{
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perror("Querying Buffer");
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return 1;
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}
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*buffer = mmap (NULL, buf.length, PROT_READ | PROT_WRITE, MAP_SHARED, fd, buf.m.offset);
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*buffer_len = buf.length;
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printf("Length: %d\nAddress: %p\n", buf.length, *buffer);
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printf("Image Length: %d\n", buf.bytesused);
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return 0;
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}
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static int capture_frame(int fd)
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{
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struct v4l2_buffer buf = {0};
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buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
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buf.memory = V4L2_MEMORY_MMAP;
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buf.index = 0;
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if(-1 == xioctl(fd, VIDIOC_QBUF, &buf))
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{
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perror("Query Buffer");
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return 1;
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}
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if(-1 == xioctl(fd, VIDIOC_STREAMON, &buf.type))
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{
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perror("Start Capture");
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return 1;
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}
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fd_set fds;
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FD_ZERO(&fds);
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FD_SET(fd, &fds);
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struct timeval tv = {0};
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tv.tv_sec = 2;
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int r = select(fd+1, &fds, NULL, NULL, &tv);
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if(-1 == r)
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{
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perror("Waiting for Frame");
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return 1;
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}
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if(-1 == xioctl(fd, VIDIOC_DQBUF, &buf))
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{
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perror("Retrieving Frame");
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return 1;
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}
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return 0;
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}
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int save_image(const char *out, uint8_t *buffer, size_t buffer_len)
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{
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printf ("saving image\n");
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int fd = open(out, O_WRONLY | O_CREAT | O_TRUNC, 0600);
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if (fd < 0) {
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fprintf(stderr, "open(\"%s\"): %m\n", out);
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return -1;
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}
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int ret = 0;
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while (buffer_len) {
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ssize_t written = write(fd, buffer, buffer_len);
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if (written < 0) {
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perror("write()");
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ret = -1;
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break;
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}
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buffer += written;
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buffer_len -= written;
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}
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close(fd);
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return ret;
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}
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int capture_image(const char *out)
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{
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int fd = open("/dev/video0", O_RDWR);
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if (fd < 0) {
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perror("Opening video device");
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return -1;
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}
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uint8_t *buffer = NULL;
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size_t buffer_len;
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int ret = print_caps(fd)
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|| init_mmap(fd, &buffer, &buffer_len)
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|| capture_frame(fd)
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|| save_image(out, buffer, buffer_len);
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close(fd);
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if (buffer)
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munmap(buffer, buffer_len);
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return ret ? -1 : 0;
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}
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