How to record and play RTSP stream from ip camera

Stuhalsky Alex

I have an ip camera that allows me to see live stream over some url: rtsp://192.168...
I want to display that stream and at the same time record it to local file.

The main question is how to do it?

I implemented stream display via QVideoWidget and QMediaPlayer.
As i can see over qt docs QMediaRecorder is used to record and store video as shown in example. QMediaRecorder uses a QMediaContent* as a source and QMediaPlayer inherits QMediaContent.

So may be it is possible to record video from QMediaPlayer?

I can't find any example of how it can be done except this one. I tried it. It compiles and runs, but it doesn't work. May be i miss something?

Or from the other hand may be it is possible to create a QCamera instance that is connected to my rtsp url?

I'm using Qt 5.12.8. OS Kubuntu 20.04

Thanks in advance.

jsulm

@Stuhalsky-Alex said in How to record and play RTSP stream from ip camera:

but it doesn't work

Did you try to find out what exactly does not work? Is the recorded file created? Does it contain anything?...

Bonnie

What platform?
AFAIK Qt doesn't support rtsp urls on Windows.
I don't think it is possible to create a QCamera connected to some live stream url.
But QMediaRecorder accepts all QMediaObject classes, not only QCamera, so it may be possible to record if Qt can play the url.

Stuhalsky Alex

Hi @jsulm. Yes, i tried.

In the first case i created file for writing manually and made sure it can be opened. The files were indeed created, but 0 bytes were written. I checked QMediaRecorder state. It have not been changed at all. Corresponding singnal was not emitting. Actual location was invalid and output location was empty string.

In the second case i tried simply to set output location in QMediaRecorder instance, but file was not created at all. Actual location was invalid, but output location contained correct QUrl path to local file.

I may miss something, because i tried many solutions during last couple of days. I can reimplement any solution that is supposed to work and check what happens.

jsulm

@Stuhalsky-Alex Can you play the stream in your Qt app?

Stuhalsky Alex

Hi @Bonnie

"What platform?"
Kubuntu 20.04.
Forgot to mention it in the topic. I will add it there too.
"I don't think it is possible to create a QCamera connected to some live stream url."
Ok. Minus one option.
"But QMediaRecorder accepts all QMediaObject classes, not only QCamera, so it may be possible to record if Qt can play the url."
Well. I will try again. May be i missed some minor mistake that breaks everything.

Stuhalsky Alex

@jsulm

"Can you play the stream in your Qt app?"
Yes, i can. Simply passing rtsp url as media for QMediaPlayer and setting video output into QVideoWidget.

AlexRNL

@Stuhalsky-Alex

Hello, I've stumbled upon your topic after running into the same issue. I'd like to dispaly and record a stream from a camera on the network. But, while I can display effortlessly the stream with a MediaPlayer widget, QMediaRecorder does not appear to support the recording of the stream from QMediaPlayer even though it implements QMediaContent.

Did you ever find a way to make it work? Or have you used a workaround?

Thanks,
Alex.

Stuhalsky Alex

@AlexRNL Hi.
I haven't found a solution and skipped this task. I will turn back to it later, but not soon i guess :)

SGaist

Hi,

Did you check with Qt 6.2 ?

Stuhalsky Alex

@SGaist Hi.
No i haven't. I can't switch to Qt6 for now so i didn't try that option.

SGaist

You can try to cheat by using a custom GStreamer pipeline that does both.

AlexRNL

@Stuhalsky-Alex I can't switch to Qt 6 yet, I'm stuck with 5.12

I have alternatives ways to record the stream, but using a QMediaRecorder seemed easy enough to set-up and as it is well-integrated into Qt it made everything easier.

I'll try to have a look at GStreamer to see if it can workaround this issue.

Thanks for your answer anyway :)