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Added v4l2 support for getting capture property CV_CAP_PROP_POS_MSEC

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dave 2013-04-02 10:31:02 -07:00
parent 87bb7ff558
commit 8db1a73102
1 changed files with 20 additions and 0 deletions
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20
modules/highgui/src/cap_v4l.cpp
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@ -154,6 +154,11 @@ the symptoms were damaged image and 'Corrupt JPEG data: premature end of data se
- USE_TEMP_BUFFER fixes the main problem (improper buffer management) and - USE_TEMP_BUFFER fixes the main problem (improper buffer management) and
prevents bad images in the first place prevents bad images in the first place
11th patch: April 2, 2013, Forrest Reiling forrest.reiling@gmail.com
Added v4l2 support for getting capture property CV_CAP_PROP_POS_MSEC.
Returns the millisecond timestamp of the last frame grabbed or 0 if no frames have been grabbed
Used to successfully synchonize 2 Logitech C310 USB webcams to within 16 ms of one another
make & enjoy! make & enjoy!
@ -320,6 +325,8 @@ typedef struct CvCaptureCAM_V4L
struct v4l2_queryctrl queryctrl; struct v4l2_queryctrl queryctrl;
struct v4l2_querymenu querymenu; struct v4l2_querymenu querymenu;
struct timeval timestamp;
/* V4L2 control variables */ /* V4L2 control variables */
int v4l2_brightness, v4l2_brightness_min, v4l2_brightness_max; int v4l2_brightness, v4l2_brightness_min, v4l2_brightness_max;
int v4l2_contrast, v4l2_contrast_min, v4l2_contrast_max; int v4l2_contrast, v4l2_contrast_min, v4l2_contrast_max;
@ -836,6 +843,9 @@ static int _capture_V4L2 (CvCaptureCAM_V4L *capture, char *deviceName)
capture->v4l2_gain_max = 0; capture->v4l2_gain_max = 0;
capture->v4l2_exposure_max = 0; capture->v4l2_exposure_max = 0;
capture->timestamp.tv_sec = 0;
capture->timestamp.tv_usec = 0;
/* Scan V4L2 controls */ /* Scan V4L2 controls */
v4l2_scan_controls(capture); v4l2_scan_controls(capture);
@ -1221,6 +1231,9 @@ static int read_frame_v4l2(CvCaptureCAM_V4L* capture) {
if (-1 == ioctl (capture->deviceHandle, VIDIOC_QBUF, &buf)) if (-1 == ioctl (capture->deviceHandle, VIDIOC_QBUF, &buf))
perror ("VIDIOC_QBUF"); perror ("VIDIOC_QBUF");
//set timestamp in capture struct to be timestamp of most recent frame
capture->timestamp = buf.timestamp;
return 1; return 1;
} }
@ -2308,6 +2321,13 @@ static double icvGetPropertyCAM_V4L (CvCaptureCAM_V4L* capture,
/* initialize the control structure */ /* initialize the control structure */
switch (property_id) { switch (property_id) {
case CV_CAP_PROP_POS_MSEC:
if (capture->FirstCapture) {
return 0;
} else {
return 1000 * capture->timestamp.tv_sec + ((double) capture->timestamp.tv_usec) / 1000;
}
break;
case CV_CAP_PROP_BRIGHTNESS: case CV_CAP_PROP_BRIGHTNESS:
capture->control.id = V4L2_CID_BRIGHTNESS; capture->control.id = V4L2_CID_BRIGHTNESS;
break; break;