Hi Jason, you need to check the handle type on the QVideoFrame. If
input->handleType() == QAbstractVideoBuffer::NoHandle then you can map the
memory directly, as you've tried. But on Mac, the handle type is
GLTextureHandle and you need to write some OpenGL code to get the texture
handle, read it, and then get at the pixels that way.
Here's a bit of code I used to do this:
// declare as class members
QByteArray _frameBuffer;
int _frameBytes;
GLuint _fbo;
// in processing function:
GLuint textureId = input->handle().toUInt();
if (_fbo == 0)
glGenFramebuffers(1, &_fbo);
_frameBytes = input->width()*input->height() * 4;
GLuint prevFbo;
glGetIntegerv(GL_FRAMEBUFFER_BINDING, (GLint *) &prevFbo);
glBindFramebuffer(GL_FRAMEBUFFER, _fbo);
glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D,
textureId, 0);
#ifdef Q_OS_IOS
glReadPixels(0, 0, input->width(), input->height(), GL_RGBA,
GL_UNSIGNED_BYTE, _frameBuffer.data());
#else
glReadPixels(0, 0, input->width(), input->height(), GL_BGRA_EXT,
GL_UNSIGNED_BYTE, _frameBuffer.data());
#endif
glBindFramebuffer(GL_FRAMEBUFFER, prevFbo);
// at this point _frameBuffer bytearray contains your pixels
Hope this saves you some of the headaches I went through as well!
Gil
On 6/14/18, 11:26 AM, "Interest on behalf of Jason H"
<[email protected] on behalf of [email protected]>
wrote:
Yes, I essentially have that (your message just made it to my email after I
sent my code)
I don't know why map() would fail, and why bits() would not be valid.
I'm on OSX, reading from an MP4...
> Sent: Thursday, June 14, 2018 at 7:12 AM
> From: "Igor Mironchik" <[email protected]>
> To: [email protected]
> Subject: Re: [Interest] (code) Cannot map videoforames for
QAbstractVideoSurface::present
>
> Hi,
>
> Start from here:
>
> bool
> Frames::present( const QVideoFrame & frame )
> {
> if( !isActive() )
> return false;
>
> QVideoFrame f = frame;
> f.map( QAbstractVideoBuffer::ReadOnly );
>
> QImage image( f.bits(), f.width(), f.height(), f.bytesPerLine(),
> QVideoFrame::imageFormatFromPixelFormat( f.pixelFormat() ) );
>
> f.unmap();
>
> emit newFrame( image.copy( image.rect() ) );
>
> return true;
> }
>
> This works for me...
>
>
> 14-Jun-18 17:52, Jason H пишет:
> > I have no idea what I'm doing wrong. Can someone this and let me know?
> > The frames I'm getting are BGR32, so I have special code for that.
> > But I'm getting the message "QVideoFrame::unmap() was called more times
then QVideoFrame::map()"
> > Which is obviously not the case.
> >
> > To restate the problems:
> > 1. I only get to present() once
> > 2. I's failing to map frames
> > 3. "then" in the message should be "than"
> >
> > Here's the first 3 lines of the .pro and complete code:
> > extractframes.pro-----
> > QT += multimedia
> > CONFIG += c++11 console
> > CONFIG -= app_bundle
> >
> > main.cpp--------------
> > #include <QAbstractVideoSurface>
> > #include <QGuiApplication>
> > #include <QMediaPlayer>
> > #include <QVideoSurfaceFormat>
> >
> > #include <QtDebug>
> >
> > class VideoSurface: public QAbstractVideoSurface {
> > int _frameNumber;
> > QVideoSurfaceFormat _format;
> > QString _prefix;
> > int _frameInterval;
> > public:
> > VideoSurface(const QString &prefix, int frameInterval):
_prefix(prefix), _frameInterval(frameInterval) { }
> >
> > bool present(const QVideoFrame &frame) override {
> > qDebug() << Q_FUNC_INFO << _frameNumber <<
frame.isValid();
> >
> > if (_frameNumber % _frameInterval == 0) {
> > QVideoFrame frame2(frame);
> > frame2.map(QAbstractVideoBuffer::ReadOnly);
> > QImage image;
> >
> > if (frame2.pixelFormat() ==
QVideoFrame::Format_BGR32) {
> > image = QImage(frame2.bits(),
frame2.width(), frame2.height(), QImage::Format_RGB32);
> > image = image.rgbSwapped();
> > } else {
> > image = QImage(frame2.bits(),
frame2.width(), frame2.height(),
QVideoFrame::imageFormatFromPixelFormat(frame2.pixelFormat()));
> > }
> >
> > frame2.unmap();
> > QString filename =
QString(_prefix).arg(_frameNumber);
> > bool result = image.save(filename);
> > qDebug() << Q_FUNC_INFO << filename << result;
> > }
> > _frameNumber ++;
> > return true;
> > }
> >
> > bool start(const QVideoSurfaceFormat &format) override {
> > qDebug() << Q_FUNC_INFO;
> > _format = format;
> > _frameNumber = 0;
> > QAbstractVideoSurface::start(format);
> > return true;
> > }
> > void stop() override {
> > qDebug() << Q_FUNC_INFO;
> > QAbstractVideoSurface::stop();
> > }
> > QList<QVideoFrame::PixelFormat>
supportedPixelFormats(QAbstractVideoBuffer::HandleType handleType) const
override
> > {
> > Q_UNUSED(handleType);
> > return QList<QVideoFrame::PixelFormat>()
> > << QVideoFrame::Format_ARGB32
> > << QVideoFrame::Format_ARGB32_Premultiplied
> > << QVideoFrame::Format_RGB32
> > << QVideoFrame::Format_RGB24
> > << QVideoFrame::Format_RGB565
> > << QVideoFrame::Format_RGB555
> > << QVideoFrame::Format_ARGB8565_Premultiplied
> > << QVideoFrame::Format_BGRA32
> > << QVideoFrame::Format_BGRA32_Premultiplied
> > << QVideoFrame::Format_BGR32
> > << QVideoFrame::Format_BGR24
> > << QVideoFrame::Format_BGR565
> > << QVideoFrame::Format_BGR555
> > << QVideoFrame::Format_BGRA5658_Premultiplied
> > << QVideoFrame::Format_AYUV444
> > << QVideoFrame::Format_AYUV444_Premultiplied
> > << QVideoFrame::Format_YUV444
> > << QVideoFrame::Format_YUV420P
> > << QVideoFrame::Format_YV12
> > << QVideoFrame::Format_UYVY
> > << QVideoFrame::Format_YUYV
> > << QVideoFrame::Format_NV12
> > << QVideoFrame::Format_NV21
> > << QVideoFrame::Format_IMC1
> > << QVideoFrame::Format_IMC2
> > << QVideoFrame::Format_IMC3
> > << QVideoFrame::Format_IMC4
> > << QVideoFrame::Format_Y8
> > << QVideoFrame::Format_Y16
> > << QVideoFrame::Format_Jpeg
> > << QVideoFrame::Format_CameraRaw
> > << QVideoFrame::Format_AdobeDng;
> > }
> >
> >
> > };
> >
> > // Command line: extractframes format interval
> > // format:QString, with %1 = frame number
> > // Example:
> > // extractframes filename.mp4 image_%1.png 30
> >
> > int main(int argc, char *argv[])
> > {
> > QGuiApplication a(argc, argv);
> > QMediaPlayer player;
> > VideoSurface surface(argv[2], QString(argv[3]).toInt());
> > QObject::connect(&player, &QMediaPlayer::mediaStatusChanged,
[=]( QMediaPlayer::MediaStatus status ) {
> > qDebug() << Q_FUNC_INFO << status;
> > });
> > QObject::connect(&player,
QOverload<QMediaPlayer::Error>::of(&QMediaPlayer::error), [=](
QMediaPlayer::Error error ) {
> > qDebug() << Q_FUNC_INFO << error;
> > });
> > QObject::connect(&player, &QMediaPlayer::stateChanged, [=](
const QMediaPlayer::State &state ) {
> > qDebug() << Q_FUNC_INFO << state;
> > if (QMediaPlayer::StoppedState == state) qApp->quit();
> > });
> >
> > player.setMedia(QUrl::fromLocalFile(argv[1]));
> > player.setVideoOutput(&surface);
> > player.setMuted(true);
> >
> > player.play();
> >
> > return a.exec();
> > }
> > _______________________________________________
> > Interest mailing list
> > [email protected]
> > http://lists.qt-project.org/mailman/listinfo/interest
>
> _______________________________________________
> Interest mailing list
> [email protected]
> http://lists.qt-project.org/mailman/listinfo/interest
>
_______________________________________________
Interest mailing list
[email protected]
http://lists.qt-project.org/mailman/listinfo/interest
_______________________________________________
Interest mailing list
[email protected]
http://lists.qt-project.org/mailman/listinfo/interest
