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V4L Buffer: Support CV_CAP_PROP_BUFFERSIZE in cap_v4l (#11047)

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tlanclos
2018-04-09 09:34:00 -05:00
committed by Vadim Pisarevsky
parent e172935658
commit a2c7afad77
1 changed files with 26 additions and 4 deletions
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modules/videoio/src/cap_v4l.cpp
+26 -4
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@@ -161,6 +161,8 @@ 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 synchronize 2 Logitech C310 USB webcams to within 16 ms of one another
12th patch: March 9, 2018, Taylor Lanclos <tlanclos@live.com>
added support for CV_CAP_PROP_BUFFERSIZE
make & enjoy!
@@ -277,6 +279,7 @@ struct CvCaptureCAM_V4L CV_FINAL : public CvCapture
__u32 palette;
int width, height;
int bufferSize;
__u32 fps;
bool convert_rgb;
bool frame_allocated;
@@ -685,7 +688,7 @@ static int _capture_V4L2 (CvCaptureCAM_V4L *capture)
capture->req = v4l2_requestbuffers();
unsigned int buffer_number = DEFAULT_V4L_BUFFERS;
unsigned int buffer_number = capture->bufferSize;
try_again:
@@ -818,6 +821,7 @@ bool CvCaptureCAM_V4L::open(const char* _deviceName)
FirstCapture = 1;
width = DEFAULT_V4L_WIDTH;
height = DEFAULT_V4L_HEIGHT;
bufferSize = DEFAULT_V4L_BUFFERS;
fps = DEFAULT_V4L_FPS;
convert_rgb = true;
deviceName = _deviceName;
@@ -1639,6 +1643,8 @@ static double icvGetPropertyCAM_V4L (const CvCaptureCAM_V4L* capture,
return CV_MAKETYPE(IPL2CV_DEPTH(capture->frame.depth), capture->frame.nChannels);
case CV_CAP_PROP_CONVERT_RGB:
return capture->convert_rgb;
case CV_CAP_PROP_BUFFERSIZE:
return capture->bufferSize;
}
if(property_id == CV_CAP_PROP_FPS) {
@@ -1820,6 +1826,18 @@ static int icvSetPropertyCAM_V4L( CvCaptureCAM_V4L* capture,
}
}
break;
case CV_CAP_PROP_BUFFERSIZE:
if ((int)value > MAX_V4L_BUFFERS || (int)value < 1) {
fprintf(stderr, "V4L: Bad buffer size %d, buffer size must be from 1 to %d\n", (int)value, MAX_V4L_BUFFERS);
retval = false;
} else {
capture->bufferSize = (int)value;
if (capture->bufferIndex > capture->bufferSize) {
capture->bufferIndex = 0;
}
retval = v4l2_reset(capture);
}
break;
default:
retval = icvSetControl(capture, property_id, value);
break;
@@ -1841,10 +1859,14 @@ static void icvCloseCAM_V4L( CvCaptureCAM_V4L* capture ){
perror ("Unable to stop the stream");
}
for (unsigned int n_buffers_ = 0; n_buffers_ < capture->req.count; ++n_buffers_)
for (unsigned int n_buffers_ = 0; n_buffers_ < MAX_V4L_BUFFERS; ++n_buffers_)
{
if (-1 == munmap (capture->buffers[n_buffers_].start, capture->buffers[n_buffers_].length)) {
perror ("munmap");
if (capture->buffers[n_buffers_].start) {
if (-1 == munmap (capture->buffers[n_buffers_].start, capture->buffers[n_buffers_].length)) {
perror ("munmap");
} else {
capture->buffers[n_buffers_].start = 0;
}
}
}