From 63ad36654d880d0ec8e0a241885bc59b6aa20e84 Mon Sep 17 00:00:00 2001
From: diegohce <diego.cena@gmail.com>
Date: Mon, 28 Oct 2024 15:45:11 -0300
Subject: [PATCH] GStreamer VideoWriter example

---
 Makefile                     |  2 +-
 cmd/gstreamer-writer/main.go | 66 ++++++++++++++++++++++++++++++++++++
 2 files changed, 67 insertions(+), 1 deletion(-)
 create mode 100644 cmd/gstreamer-writer/main.go

diff --git a/Makefile b/Makefile
index ccc035d6..6469ea5b 100644
--- a/Makefile
+++ b/Makefile
@@ -214,7 +214,7 @@ build_cuda:
 	mkdir build
 	cd build
 	rm -rf *
-	cmake -D CMAKE_BUILD_TYPE=RELEASE -D CMAKE_INSTALL_PREFIX=/usr/local -D BUILD_SHARED_LIBS=${BUILD_SHARED_LIBS} -D OPENCV_EXTRA_MODULES_PATH=$(TMP_DIR)opencv/opencv_contrib-$(OPENCV_VERSION)/modules -D BUILD_DOCS=OFF -D BUILD_EXAMPLES=OFF -D BUILD_TESTS=OFF -D BUILD_PERF_TESTS=ON -D BUILD_opencv_java=NO -D BUILD_opencv_python=NO -D BUILD_opencv_python2=NO -D BUILD_opencv_python3=NO -D WITH_JASPER=OFF -D WITH_TBB=ON -DOPENCV_GENERATE_PKGCONFIG=ON -DWITH_CUDA=ON -DENABLE_FAST_MATH=1 -DCUDA_FAST_MATH=1 -DWITH_CUBLAS=ON -DCUDA_TOOLKIT_ROOT_DIR=/usr/local/cuda/ -DBUILD_opencv_cudacodec=OFF -D WITH_CUDNN=ON -D OPENCV_DNN_CUDA=ON -D CUDA_GENERATION=Auto -DOPENCV_ENABLE_NONFREE=ON -D WITH_GSTREAMER=OFF ..
+	cmake -D CMAKE_BUILD_TYPE=RELEASE -D CMAKE_INSTALL_PREFIX=/usr/local -D BUILD_SHARED_LIBS=${BUILD_SHARED_LIBS} -D OPENCV_EXTRA_MODULES_PATH=$(TMP_DIR)opencv/opencv_contrib-$(OPENCV_VERSION)/modules -D BUILD_DOCS=OFF -D BUILD_EXAMPLES=OFF -D BUILD_TESTS=OFF -D BUILD_PERF_TESTS=ON -D BUILD_opencv_java=NO -D BUILD_opencv_python=NO -D BUILD_opencv_python2=NO -D BUILD_opencv_python3=NO -D WITH_JASPER=OFF -D WITH_TBB=ON -DOPENCV_GENERATE_PKGCONFIG=ON -DWITH_CUDA=ON -DENABLE_FAST_MATH=1 -DCUDA_FAST_MATH=1 -DWITH_CUBLAS=ON -DCUDA_TOOLKIT_ROOT_DIR=/usr/local/cuda/ -DBUILD_opencv_cudacodec=OFF -D WITH_CUDNN=ON -D OPENCV_DNN_CUDA=ON -D CUDA_GENERATION=Auto -DOPENCV_ENABLE_NONFREE=ON -D WITH_GSTREAMER=ON ..
 	$(MAKE) -j $(shell nproc --all --ignore 1)
 	$(MAKE) preinstall
 	cd -
diff --git a/cmd/gstreamer-writer/main.go b/cmd/gstreamer-writer/main.go
new file mode 100644
index 00000000..c70baa53
--- /dev/null
+++ b/cmd/gstreamer-writer/main.go
@@ -0,0 +1,66 @@
+/*
+	GStreamer Video Writer
+
+What it does:
+
+	Captures video from webcam and outputs the frames to a gocv VideoWriter
+
+How to run:
+
+	go run main.go
+
+To receive the video feed run in a terminal:
+
+	gst-launch-1.0 udpsrc port=5000 ! application/x-rtp, encoding-name=MJPG ! rtpjpegdepay ! jpegdec !  videoconvert ! xvimagesink
+*/
+package main
+
+import (
+	"fmt"
+
+	"gocv.io/x/gocv"
+)
+
+const (
+	gstreamerPipe = "appsrc ! videoconvert ! video/x-raw,format=YUY2,width=640,height=480,framerate=30/1 ! jpegenc ! rtpjpegpay ! udpsink host=127.0.0.1 port=5000"
+)
+
+func main() {
+
+	cap, err := gocv.VideoCaptureDevice(0)
+	if err != nil {
+		panic(err)
+	}
+	defer cap.Close()
+	cap.Set(gocv.VideoCaptureFrameWidth, 640.0)
+	cap.Set(gocv.VideoCaptureFrameHeight, 480.0)
+
+	wrt, err := gocv.VideoWriterFileWithAPI(gstreamerPipe,
+		gocv.VideoCaptureGstreamer, "YUY2", 30.0, 640, 480, true)
+	if err != nil {
+		panic(err)
+	}
+	defer wrt.Close()
+
+	if !wrt.IsOpened() {
+		panic("wrt is not opened")
+	}
+
+	frame := gocv.NewMat()
+	defer frame.Close()
+
+	for {
+		cap.Read(&frame)
+
+		if frame.Empty() {
+			fmt.Println("empty frame")
+			continue
+		}
+
+		if err := wrt.Write(frame); err != nil {
+			fmt.Println(err)
+		}
+
+	}
+
+}