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#include <assert.h> | |
#include <errno.h> | |
#include <fcntl.h> | |
#include <linux/videodev2.h> | |
#include <stdio.h> | |
#include <string.h> | |
#include <sys/ioctl.h> | |
#include <sys/mman.h> | |
#include <sys/stat.h> | |
#include <sys/types.h> | |
#define COUNT 4 | |
#define sysfail(msg) { printf ("%s failed: %s\n", (msg), strerror (errno)); return -1; } | |
int | |
main (int argc, char **argv) | |
{ | |
struct v4l2_format fmt = { 0 }; | |
struct v4l2_requestbuffers breq = { 0 }; | |
struct v4l2_buffer bufs[COUNT]; | |
void *data[COUNT] = { 0 }; | |
int fd; | |
int i; | |
fd = open (argv[1], O_RDWR); | |
if (fd < 0) | |
sysfail("open"); | |
fmt.type = V4L2_BUF_TYPE_VIDEO_OUTPUT; | |
fmt.fmt.pix.width = 320; | |
fmt.fmt.pix.height = 240; | |
fmt.fmt.pix.pixelformat = V4L2_PIX_FMT_RGB32; | |
if (ioctl (fd, VIDIOC_S_FMT, &fmt) < 0) | |
sysfail ("S_FMT"); | |
breq.count = COUNT; | |
breq.type = V4L2_BUF_TYPE_VIDEO_OUTPUT; | |
breq.memory = V4L2_MEMORY_MMAP; | |
if (ioctl (fd, VIDIOC_REQBUFS, &breq) < 0) | |
sysfail ("REQBUFS"); | |
assert (breq.count == COUNT); | |
memset (bufs, 0, sizeof (bufs)); | |
for (i = 0; i < COUNT; i++) { | |
int p; | |
bufs[i].index = i; | |
bufs[i].type = breq.type; | |
bufs[i].memory = breq.memory; | |
if (ioctl (fd, VIDIOC_QUERYBUF, &bufs[i]) < 0) | |
sysfail ("QUERYBUF"); | |
data[i] = mmap (NULL, bufs[i].length, PROT_WRITE, MAP_SHARED, fd, bufs[i].m.offset); | |
if (data[i] == MAP_FAILED) | |
sysfail ("mmap"); | |
for (p = 0; p < (bufs[i].bytesused >> 2); p++) | |
((unsigned int*)data[i])[p] = 0xFF00FF00; | |
} | |
if (ioctl (fd, VIDIOC_QBUF, &bufs[0]) < 0) | |
sysfail ("QBUF"); | |
if ((bufs[0].flags & V4L2_BUF_FLAG_QUEUED) == 0) { | |
printf ("BUG #1: Driver should set the QUEUED flag before returning from QBUF\n"); | |
bufs[0].flags |= V4L2_BUF_FLAG_QUEUED; | |
} | |
if (ioctl (fd, VIDIOC_STREAMON, &fmt.type) < 0) | |
sysfail ("STREAMON"); | |
i = 1; | |
while (1) { | |
struct v4l2_buffer buf = { 0 }; | |
if (ioctl (fd, VIDIOC_QBUF, &bufs[i]) < 0) | |
sysfail ("QBUF"); | |
if ((bufs[i].flags & V4L2_BUF_FLAG_QUEUED) == 0) { | |
printf ("BUG #1: Driver should set the QUEUED flag before returning from QBUF\n"); | |
bufs[i].flags |= V4L2_BUF_FLAG_QUEUED; | |
} | |
buf.type = breq.type; | |
buf.memory = breq.memory; | |
if (ioctl (fd, VIDIOC_DQBUF, &buf) < 0) | |
sysfail ("DBBUF"); | |
i = buf.index; | |
if ((bufs[i].flags & V4L2_BUF_FLAG_QUEUED) == 0) { | |
printf ("BUG #2: Driver should not dequeue a buffer that was not intially queued\n"); | |
} | |
assert (bufs[i].flags & V4L2_BUF_FLAG_QUEUED); | |
assert (!(buf.flags & (V4L2_BUF_FLAG_QUEUED | V4L2_BUF_FLAG_DONE))); | |
bufs[i] = buf; | |
} | |
return 0; | |
} |
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