QTMultimedia FFMPEG backend preview

[sethsource]

on the docs, there is "You can test the FFmpeg backend right now by using a Qt build that has FFmpeg enabled and setting the QT_MEDIA_BACKEND environment variable to ffmpeg:"

After setting this environment variable using my clean install of 6.4 it still doesn't work. it says ffmpeg isnt supported.

How do i test this preview out? i've been waiting for the ability to use an RTSP stream on windows compiled programs for the longest time using QT.

This ofcourse works flawlessly on Linux. Just install 6.4, open my project, build, and boom. But on windows I cant get it to work. I need some help figuring out the steps to test out this preview.

I've researched online and found posts with people compiling their own QTMultimedia with ffmpeg, but failed to produce any steps or details.

[sethsource]

I also just attempted this on 6.5 release and 6.6 preview. Its very odd, with the ffmpeg environment variable enabled, there is no error output, but it doesnt work like it should.

[sethsource]

On Linux, this code displays an RTSP stream. and I know that ffmpeg supports this, as i've created a .NET program using ffmpeg to do something similar. I just want to make this with QT/QML

import QtQuick
import QtMultimedia
import QtQml.Models 2.3
Window {
    width: 640
    height: 480
    visible: true
    title: qsTr("CSACamera")
    color: "#000000"
    Video {
            id: stream
            anchors.fill: parent
            focus: true
            source: "rtsp://admin:CSACamera18@192.168.2.18/h264_stream"
            opacity: 1.0
            fillMode: Image.Stretch
            muted: true
            onStopped: stream.play()
            Timer {
                    interval: 300000; running: true; repeat: true
                    onTriggered: {
                        console.log("Log: Refresh")
                        stream.stop()
                        stream.source="rtsp://admin:CSACamera18@192.168.2.18/h264_stream"
                        stream.play()
                    }
                }
//            onErrorChanged: {
//                console.log("VIDEO ERROR")
//                stream.stop()
//                stream.source="rtsp://admin:CSACamera18@192.168.2.18/h264_stream"
//                stream.play()
//            }

            Text {
                id: text1
                width: 73
                height: 18
                color: "#ffffff"
                text: qsTr("Audio: False")
                anchors.left: parent.left
                anchors.top: parent.top
                font.pixelSize: 15
                anchors.leftMargin: 0
                anchors.topMargin: 0
            }

            Keys.onPressed: (event)=> {
                if(event.key === Qt.Key_M) {
                    if(text1.text === "Audio: True") {
                        text1.text = "Audio: False"
                        stream.muted = true
                    } else if (text1.text === "Audio: False") {
                        text1.text = "Audio: True"
                        stream.muted = false
                    }
                }
            }
    }
}

[sethsource]

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[sethsource]

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[sethsource]

buimp .

[SGaist]

Hi,

Did you check whether the plugin was deployed ?
If not, did you try to build it yourself ?

[sethsource]

@SGaist How would i check to see if it's deployed? and also there's no instructions anywhere on how to build the preview with FFMPEG included

[JoeCFD]

@sethsource from Qt6.5, FFMPEG comes as default. Check the folder /plugins/multimedia and you will be able to see the plugin is there. If you use Qt6.4, you have to set QT_MEDIA_BACKEND. From all changes they are making, you may not be surprised by issues. Qt6.5 is under beta and Qt6.6 is under dev. I guess you have to be patient with this app.

[sethsource]

QT6.4 didnt work with FFMPEG out of the box, as well as 6.6. I'll try 6.5.

[sethsource]

Okay now we're getting somewhere. QT6.5 with msvc allows me to run my program without yelling at me. only thing now is it seems it wants me to specify a "decoding framework". heres the output:

Cant seem to find any environment variables on the internet that i can use.

Available HW decoding frameworks:
dxva2
d3d11va

[sethsource]

I read on an ffmpeg forum that people make the use of dxva2 and d3d11va through a command line argument for video...
"ffmpeg -hwaccel dxva2 -threads 1 -i INPUT -f null - -benchmark"

but this is completely unrelated to QT. I attempted to use an envar for hwaccel and using command line arg and no difference.