QVideoFrame constructor with QVideoFrameFormat fails

[felsi]

Hello!
I am using QVideoFrame::QVideoFrame(const QVideoFrameFormat &format) to create a new QVideoFrame and i might have found a little bug. For demonstration:

    QVideoFrame frame_dst_1 = QVideoFrame(frame_src);
    QVideoFrame frame_dst_2 = QVideoFrame(frame_src.surfaceFormat());
    frame_dst_1.map(QVideoFrame::ReadOnly);
    frame_dst_2.map(QVideoFrame::ReadOnly);
    qDebug() << "frame_src  : mappedBytes:" << frame_src.mappedBytes(0);
    qDebug() << "frame_dst_1: mappedBytes:" << frame_dst_1.mappedBytes(0);
    qDebug() << "frame_dst_2: mappedBytes:" << frame_dst_2.mappedBytes(0);

result:
frame_src : mappedBytes: 983040
frame_dst_1: mappedBytes: 983040
frame_dst_2: mappedBytes: 921600

The pixelFormat is Format_YUV420P. It happens on Debian 11 with Qt version 6.7.1, with Qt version 6.3.2 it works like expected.
I am just guessing, but maybe it is related to switching from gstreamer to ffmpeg...

[vincent9874]

Report the issue to Qt’s bug tracker, mentioning the different mappedBytes values between Qt versions 6.7.1 and 6.3.2, and the potential link to the switch from gstreamer to ffmpeg.

[felsi]

Ok, thank you for your response.
I created a bug report.
https://bugreports.qt.io/browse/QTBUG-126359