127 lines
3.7 KiB
C++
127 lines
3.7 KiB
C++
// This file is part of OpenCV project.
|
|
// It is subject to the license terms in the LICENSE file found in the top-level directory
|
|
// of this distribution and at http://opencv.org/license.html.
|
|
//
|
|
// Copyright (C) 2019 Intel Corporation
|
|
|
|
#ifndef OPENCV_GAPI_STREAMING_CAP_HPP
|
|
#define OPENCV_GAPI_STREAMING_CAP_HPP
|
|
|
|
/**
|
|
* YOUR ATTENTION PLEASE!
|
|
*
|
|
* This is a header-only implementation of cv::VideoCapture-based
|
|
* Stream source. It is not built by default with G-API as G-API
|
|
* doesn't depend on videoio module.
|
|
*
|
|
* If you want to use it in your application, please make sure
|
|
* videioio is available in your OpenCV package and is linked to your
|
|
* application.
|
|
*
|
|
* Note for developers: please don't put videoio dependency in G-API
|
|
* because of this file.
|
|
*/
|
|
#include <chrono>
|
|
|
|
#include <opencv2/videoio.hpp>
|
|
#include <opencv2/gapi/garg.hpp>
|
|
#include <opencv2/gapi/streaming/meta.hpp>
|
|
|
|
namespace cv {
|
|
namespace gapi {
|
|
namespace wip {
|
|
|
|
/**
|
|
* @brief OpenCV's VideoCapture-based streaming source.
|
|
*
|
|
* This class implements IStreamSource interface.
|
|
* Its constructor takes the same parameters as cv::VideoCapture does.
|
|
*
|
|
* Please make sure that videoio OpenCV module is available before using
|
|
* this in your application (G-API doesn't depend on it directly).
|
|
*
|
|
* @note stream sources are passed to G-API via shared pointers, so
|
|
* please gapi::make_src<> to create objects and ptr() to pass a
|
|
* GCaptureSource to cv::gin().
|
|
*/
|
|
class GCaptureSource: public IStreamSource
|
|
{
|
|
public:
|
|
explicit GCaptureSource(int id) : cap(id) { prep(); }
|
|
explicit GCaptureSource(const std::string &path) : cap(path) { prep(); }
|
|
|
|
// TODO: Add more constructor overloads to make it
|
|
// fully compatible with VideoCapture's interface.
|
|
|
|
protected:
|
|
cv::VideoCapture cap;
|
|
cv::Mat first;
|
|
bool first_pulled = false;
|
|
int64_t counter = 0;
|
|
|
|
void prep()
|
|
{
|
|
// Prepare first frame to report its meta to engine
|
|
// when needed
|
|
GAPI_Assert(first.empty());
|
|
cv::Mat tmp;
|
|
if (!cap.read(tmp))
|
|
{
|
|
GAPI_Assert(false && "Couldn't grab the very first frame");
|
|
}
|
|
// NOTE: Some decode/media VideoCapture backends continue
|
|
// owning the video buffer under cv::Mat so in order to
|
|
// process it safely in a highly concurrent pipeline, clone()
|
|
// is the only right way.
|
|
first = tmp.clone();
|
|
}
|
|
|
|
virtual bool pull(cv::gapi::wip::Data &data) override
|
|
{
|
|
if (!first_pulled)
|
|
{
|
|
GAPI_Assert(!first.empty());
|
|
first_pulled = true;
|
|
data = first; // no need to clone here since it was cloned already
|
|
}
|
|
else
|
|
{
|
|
if (!cap.isOpened()) return false;
|
|
|
|
cv::Mat frame;
|
|
if (!cap.read(frame))
|
|
{
|
|
// end-of-stream happened
|
|
return false;
|
|
}
|
|
// Same reason to clone as in prep()
|
|
data = frame.clone();
|
|
}
|
|
// Tag data with seq_id/ts
|
|
const auto now = std::chrono::system_clock::now();
|
|
const auto dur = std::chrono::duration_cast<std::chrono::microseconds>
|
|
(now.time_since_epoch());
|
|
data.meta[cv::gapi::streaming::meta_tag::timestamp] = int64_t{dur.count()};
|
|
data.meta[cv::gapi::streaming::meta_tag::seq_id] = int64_t{counter++};
|
|
return true;
|
|
}
|
|
|
|
virtual GMetaArg descr_of() const override
|
|
{
|
|
GAPI_Assert(!first.empty());
|
|
return cv::GMetaArg{cv::descr_of(first)};
|
|
}
|
|
};
|
|
|
|
// NB: Overload for using from python
|
|
GAPI_EXPORTS_W cv::Ptr<IStreamSource> inline make_capture_src(const std::string& path)
|
|
{
|
|
return make_src<GCaptureSource>(path);
|
|
}
|
|
|
|
} // namespace wip
|
|
} // namespace gapi
|
|
} // namespace cv
|
|
|
|
#endif // OPENCV_GAPI_STREAMING_CAP_HPP
|