how to use gocv for ipc

[yyf1986]

I install gocv is ok,and use device 0 is ok,but I don't know how to use device is a IPC

[deadprogram]

Sorry what is an "IPC"? Can you please elaborate on what you are trying to do? Thanks.

[yyf1986]

I want use IP Camera,like "rtsp://admin:[email protected]"

[deadprogram]

GoCV already has streaming support, for example you can use the capwindow example to stream a URL like this:

$ go run ./cmd/capwindow/main.go http://187.157.229.132/mjpg/video.mjpg
Start reading device: http://187.157.229.132/mjpg/video.mjpg

Since OpenCV is normally built with ffmpeg and/or gstreamer, you should be able to to do something like this with the rtsp protocol:

webcam, err := gocv.OpenVideoCapture("rtsp://admin:[email protected]")

Hope that helps!

[yyf1986]

I install gocv refer https://github.com/hybridgroup/gocv#windows, and when I use 0 for deviceID is ok,but use like 'rtsp://admin:[email protected]' is not ok. my code like:

package main

import (
	"fmt"
	"gocv.io/x/gocv"
)

func main() {
	deviceID := "rtsp://admin:[email protected]"
	//deviceID := "http://187.157.229.132/mjpg/video.mjpg"

	webcam, err := gocv.OpenVideoCapture(deviceID)
	if err != nil {
		fmt.Printf("Error opening video capture device: %v\n", deviceID)
		return
	}
	defer webcam.Close()
	//webcam, _ := gocv.OpenVideoCapture(1)
	window := gocv.NewWindow("Hello")
	defer window.Close()

	img := gocv.NewMat()
	defer img.Close()

	fmt.Printf("Start reading device: %v\n", deviceID)

	for {
		if ok := webcam.Read(&img); !ok {
			fmt.Printf("Device closed: %v\n", deviceID)
			return
		}
		if img.Empty() {
			continue
		}

		window.IMShow(img)
		if window.WaitKey(1) == 27 {
			break
		}
	}
}

[DoubleChuang]

Try using quotes like the following command:

./gocv "rtsp://admin:[email protected]"

[yyf1986]

D:\GoCode\src\agent>main.exe rtsp://admin:1234@[email protected] Error opening video capture device: rtsp://admin:1234@[email protected]

when I run like "main.exe 0" is ok.

[deadprogram]

I think @DoubleChuang was suggesting you use this form of the command:

main.exe "rtsp://admin:1234@[email protected]"

However from the message displayed, I do not think that is your problem.

I wonder if you might need to make some change to the Windows firewall settings to allow the compiled program to open a port. You should investigate that, I have run into similar issues in the past.

[yyf1986]

@deadprogram I close the Windows firewall，but the command still not work

[deadprogram]

How did you build OpenCV?

[yyf1986]

@deadprogram I install gocv refer https://github.com/hybridgroup/gocv#windows

[kuailehaibin]

@yyf1986 The right uri maybe rtsp://<username>:<password>@<ip>:<port>/Streaming/channels/<stream_number>, such as rtsp://admin:[email protected]:554/Streaming/channels/1/

• <username> and <password> are the login authentication element
• <ip> is the IP-address of camera
• <port> is the port number of RTSP protocol, the default value is 554
• <stream_number> is the channel number, if it is equal to 1, it indicates that the main stream is being captured; if it is equal to 2, it indicates that the secondary stream is being captured

[yyf1986]

@kuailehaibin when i use vlc to play with url "rtsp://admin:[email protected]" is ok,and I use python-opencv to captured is ok with url "rtsp://admin:[email protected]"

[kuailehaibin]

OK

[yyf1986]

when I use Ubuntu，the problem is solve.

[chaoswong1981]

I have the same problem. I think this maybe cause by ffmpeg? I search how to use OpenCV to play ffmpeg, and i find this need ffmpeg support. Maybe the "Windows Install" need to add build ffmpeg part?

[TangShuancheng]

@yyf1986 Are you unable to use it under the win10 environment and the error opening video capture device appears? This is also the case under win10, I do not know what the reason is.

[yyf1986]

@TangShuancheng yes, so I use Ubuntu to use it

[GlennZeng]

I come across the same problem as yours，the problem is： Error opening video capture device: rtsp://admin:[email protected]

[alebeta90]

Hi all,

I found the same problem in my dev env Fedora 35. Compilation went well and I can read my local camera as device 0. But having the same issue to capture the remote device with rtsp protocol. I can access the device using vlc and ffplay from the same environment.

I'm wondering if it might be a problem related to the OS and the ffmpeg library ? I can see @yyf1986 on ubuntu got working and reading many other issues in this repo other users are running it without problems.

there is a way to verbose the ouput of gocv?

kind regards

[alebeta90]

Hi,

in my case, it was a problem related with the package FFMPEG of Fedora. At the moment of compiling openCV, it was not able to find FFMPEG in the system. I needed to compile FFMPEG with specific flags in order to be detected by the openCV compilation process.

This is the line to configure FFMPEG before installing openCV

sudo ./configure --pkgconfigdir=/usr/lib64/pkgconfig --incdir=/usr/include --prefix=/usr --bindir=/usr/bin --datadir=/usr/share/ffmpeg --docdir=/usr/share/doc/ffmpeg --libdir=/usr/lib64 --mandir=/usr/share/man --arch=x86_64 --disable-x86asm

Similar issue exists in the openCV repo itself.

The issue does not exist in other distros like ubuntu for example.

Hope it can help other people in future.