I have OMAP5432 EVM running Android 4.2 with 4 USB connected Logitech C270 cameras. I use V4L2 driver from NDK C-code to open and stream from cameras in MJPEG mode. Everything works fine except right after power cycling cameras.
After power cycling cameras two or sometimes three of them come up correctly but one start spitting frame buffers that are missing MJPEG SOI 0xFF, 0xD8 at the beginning of the buffer while EOI 0xFF, 0xD9 is present.
Closing and reopening offending camera files /dev/videoX with posix close() fixes the problem for good till next power cycle.
Never happens with single camera connected, only with 3 or 4 of those.
I've tried replacing USB hubs, connecting cameras directly to no avail.
struct v4l2_format fm = {0};
fm.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
int r = xioctl(c->fd, VIDIOC_G_FMT, &fm);
if (r != 0) {
printf("VIDIOC_G_FMT %s r=%d error %d, %s", c->name, r, errno, strerror(errno));
return -1;
}
fm.fmt.pix.width = c->width; // 640
fm.fmt.pix.height = c->height; // 480
fm.fmt.pix.pixelformat = V4L2_PIX_FMT_MJPEG;
fm.fmt.pix.field = V4L2_FIELD_ANY;
fm.fmt.pix.colorspace = V4L2_COLORSPACE_JPEG;
if (c->fm != V4L2_PIX_FMT_MJPEG) {
unsigned int min = fm.fmt.pix.width * 2;
if (fm.fmt.pix.bytesperline < min) {
fm.fmt.pix.bytesperline = min;
}
min = fm.fmt.pix.bytesperline * fm.fmt.pix.height;
if (fm.fmt.pix.sizeimage < min) {
fm.fmt.pix.sizeimage = min;
}
} else {
fm.fmt.pix.bytesperline = 0;
fm.fmt.pix.sizeimage = 0;
}
r = xioctl(c->fd, VIDIOC_S_FMT, &fm);
followed by
static int init_mmap(camera_t_* c) {
struct v4l2_requestbuffers rq = {0};
rq.count = BUFFERS;
rq.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
rq.memory = V4L2_MEMORY_MMAP;
if (xioctl(c->fd, VIDIOC_REQBUFS, &rq) != 0) {
if (EINVAL == errno) {
printf("%s does not support memory mapping", c->name);
return -1;
} else {
printf("VIDIOC_REQBUFS error %d, %s", errno, strerror(errno));
return -1;
}
}
if (rq.count < 2) {
printf("Insufficient buffer memory on %s", c->name);
return -1;
}
c->buffers = malloc(rq.count * sizeof(buffer_t));
if (c->buffers == null) {
printf("out of memory");
return -1;
}
c->n_buffers = rq.count;
for (int i = 0; i < rq.count; i++) {
struct v4l2_buffer b = {0};
b.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
b.memory = V4L2_MEMORY_MMAP;
b.index = i;
if (xioctl(c->fd, VIDIOC_QUERYBUF, &b) != 0) {
printf("VIDIOC_QUERYBUF error %d, %s", errno, strerror(errno));
return -1;
}
c->buffers[i].length = b.length;
c->buffers[i].start = mmap(null, b.length, PROT_READ | PROT_WRITE, MAP_SHARED, c->fd, b.m.offset);
if (c->buffers[i].start == MAP_FAILED) {
printf("mmap error %d, %s", errno, strerror(errno));
return -1;
}
}
return 0;
}
the data I am getting back is like this:
missing FFD8 tag 0x688fb000 bytes=6946 length=213333
0x688fb000: AB 74 10 0C EE FD 34 FB B3 FA 3E D1 60 9D 33 B0 ?t????4???>?`?3?
0x688fb010: F1 83 7B 8A AF B8 F9 BF EF 33 EE FF 89 91 7F 9F ??{??????3?????
0x688fb020: 47 EF A4 B9 73 1C BC FB AD 46 6A D5 22 A2 2C 32 G???s????Fj?"?,2
0x688fb030: 2B A8 71 7E 56 56 73 23 15 7B 11 B2 F0 FA AA D3 +?q~VVs#?{??????
.............
0x688fcae2: 00 A2 80 0A 28 03 FF D5 C6 A2 80 0A 28 00 A2 80 ????(???????(???
0x688fcaf2: 0A 28 00 A2 80 0A 28 00 A2 80 0A 28 00 A2 80 0A ?(????(????(????
0x688fcb02: 28 03 FF D6 C6 A2 80 0A 28 00 A2 80 0A 28 00 A2 (???????(????(??
0x688fcb12: 80 0A 28 00 A2 80 0A 28 00 A2 80 0A 28 03 FF D9 ??(????(????(???
and it is the same data for each of dequeued buffer...
Is it something wrong with C270 or V4L2 or something wrong with my code? Anybody experience similar issues?
