Qt Gstreamer : get RTP timestamp

Qt_User

Hi all,

I am developping a Qt program to play rtp video stream.

I use gstreamer (QGst) to play the video. The video plays well but I would like to extract the RTP timestamp from the RTP header from the stream.

Does anybody know a way to do it ?

Maybe getting a "QGstBuffer":http://gstreamer.freedesktop.org/data/doc/gstreamer/head/qt-gstreamer/html/classQGst_1_1Buffer.html could be a solution ? It has a timeStamp() method...

Thank you

Here is the pipeline configuration :

@
/*
.----------.
| rtpbin |
.-------. | | .---------. .-------. .-------------.
RTP RECV |udpsrc | | | |h264depay| |h264dec| |autovideosink|
| src->recv_rtp recv_rtp->sink src->sink src->sink |
'-------' | | '---------' '-------' '-------------'
| |
'----------'
*/

void VideoControler::playRTP(int port)
{
m_pipeline = QGst::Pipeline::create();

QGst::ElementPtr rtpbin = QGst::ElementFactory::make("gstrtpbin");
if (!rtpbin) {
    qFatal("Failed to create gstrtpbin");
}
m_pipeline->add(rtpbin);

// video content
// receiving the vidéo
QGst::ElementPtr rtpudpsrc = QGst::ElementFactory::make("udpsrc");
if (!rtpudpsrc) {
    qFatal("Failed to create udpsrc. Aborting...");
}
rtpudpsrc->setProperty("port", port);
rtpudpsrc->setProperty("caps", QGst::Caps::fromString("application/x-rtp,"
                                                      "media=(string)video,"
                                                      "clock-rate=(int)90000,"
                                                      "encoding-name=(string)H264"));
rtpudpsrc->setProperty("sync", false);
m_pipeline->add(rtpudpsrc);
rtpudpsrc->link(rtpbin, "recv_rtp_sink_1");

// watch for the receiving side src pads
QGlib::connect(rtpbin, "pad-added", this, &VideoControler::onRtpBinPadAdded);

// watch the bus
m_pipeline->bus()->addSignalWatch();
QGlib::connect(m_pipeline->bus(), "message::error", this, &VideoControler::onBusErrorMessage);

// switch to the video view and connect the video widget
m_player->watchPipeline(m_pipeline);

// go!
m_pipeline->setState(QGst::StatePlaying);

}

void VideoControler::onRtpBinPadAdded(const QGst::PadPtr & pad)
{
QGst::ElementPtr bin;

try {
    bin = QGst::Bin::fromDescription(
        "rtph264depay ! ffdec_h264 ! ffmpegcolorspace ! autovideosink"
    );
} catch (const QGlib::Error & error) {
    qCritical() << error;
    qFatal("One ore more required elements are missing. Aborting...");
}

m_pipeline->add(bin);
bin->syncStateWithParent();
pad->link(bin->getStaticPad("sink"));

}
@

Qt_User

Hi !

I found how to extract RTP timestamp (and more).

Here is my new pipeline : http://www.asciiflow.com/#5094128708993859588

@

/*
+-------+ +--------+
|udpsrc | |appsink |
RTP RECV | | | |
| src->sink |
+-------+ +--------+
+
|
| queue
pushBuffer(pullBuffer())|
| +----------+ +---------+ +-------+ +-------------+
v +----------+ | | |h264depay| |h264dec| |autovideosink|
+-------+ | rtpbin | | | | | | | | |
|appsrc | | | +----+ src->sink src->sink src->sink |
| | | | | +------+ +---------+ +-------+ +-------------+
| src->recv_rtp recv_rtp->sink tee |
+-------+ | | | +------+ +---------+ +-------+ +---------+ +------+ +--------+
| | +----+ | |h264depay| |h264dec| |theoraenc| |oggmux| |filesink|
+----------+ | | | | | | | | | | | |
| src->sink src->sink src->sink src->sink src->sink |
+----------+ +---------+ +-------+ +---------+ +------+ +--------+

                                                                             queue

*/
@

And follow this example to create a personal sink :
http://gstreamer.freedesktop.org/data/doc/gstreamer/head/qt-gstreamer/html/examples_2appsink-src_2main_8cpp-example.html

This way you can access to a raw RTP packet.

ali.pro

Could you put the headers of your code.