TMDSIDK574: Video acceleration with Qt multimedia

Part Number: TMDSIDK574

Hi,

my name is Thomas and im currently working with the evaluation board TI TMDSIDK574 and the according SDK with linux. The sdk version is 5.00.00.15. The Qt Version in this sdk is Qt 5.9.6

I'm currently trying to create a Qt application, showing a viedo. Qt is configured to use gstreamer.

First thing I've done was to try to show the video with gstreamer alone, which worked fine with the following pipeline:

gst-launch-1.0 playbin uri="file:///home/root/VideoForschung/am5728-gst-tests/video-samples/TearOfSteel-Short-720x420.mpeg2" video-sink=waylandsink

...  Using top, I could verify, that the CPU is utilized in this case for approximately 4%, which lets me assume, that hardware acceleration is properly used.

Now I built a small QML based application, which does the same in QT. Looks like the following:

import QtQuick 2.9
import QtQuick.Window 2.2
import QtMultimedia 5.9
import QtQuick.Layouts 1.3
Window {
    visible: true

    property string videoFile : "file:///home/root/VideoForschung/am5728-gst-tests/video-samples/TearOfSteel-Short-720x420.mpeg2"
    width: 1280
    height: 800
    title: qsTr("Hello World")
    RowLayout {
        anchors.fill: parent
        Rectangle {
            anchors.fill: parent
            Layout.fillWidth: true
            Layout.minimumWidth: 720
            Layout.minimumHeight: 420

            color: "black"

            MediaPlayer {
                id: player
                source : videoFile
                autoPlay: true
            }

            VideoOutput {
                id: videoOutput
                width: 720
                height: 420
                source: player
                orientation : 1
            }
        }
    }
}

This application works too, but 'top' shows me a CPU load of 95%, although the resolution is not yet the resolution I intend to display. Using GST_DEBUG settings showed me, that gstreamer is used in this case too and even the ducatih264 decoder is used.

My question is now: Is this the normal performance in connection with QT, or have I missed something?

Thank you in advance

Thomas