qmediaplayer no video

pauledd

Hi there,
I try to playback a video with qmediaplayer but it shows only a blank window and no errors so far.
The videofile is: ( Video: h264 (High) (avc1 / 0x31637661), yuv420p, 640x360, 560 kb/s, 29.67 fps, 29.67 tbr, 11392 tbn, 59.33 tbc (default) )
Qtmultimedia was compiled with gstreamer 1.0 support, GStreamer 1.6.3 installed. Plugins good,bad,ugly (1.0) are installed.
The videofile itself plays fine with "gst-launch-1.0 filesrc location=~/store/tmp/out_s.mp4 ! decodebin ! autovideosink"

main.cpp:

#include "mainwindow.h"
#include <QApplication>
#include <QMediaPlayer>
#include <QVideoWidget>
#include <QDebug>

int main(int argc, char *argv[])
{
	QApplication a(argc, argv);
	QMediaPlayer* player = new QMediaPlayer;
	QVideoWidget* vw = new QVideoWidget;
	
	player->setVideoOutput(vw);
	player->QMediaPlayer::setMedia(QUrl::fromLocalFile("/home/paul/store/tmp/out_s.mp4"));
	
	vw->show();
	player->play();
	
	qDebug() << player->state();

	return a.exec();
}

project.pro :

#-------------------------------------------------
#
# Project created by QtCreator 2016-07-08T16:22:05
#
#-------------------------------------------------

QT       += core gui multimedia multimediawidgets
greaterThan(QT_MAJOR_VERSION, 4): QT += widgets
TARGET = mjpeg_test
TEMPLATE = app
SOURCES += main.cpp\
        mainwindow.cpp
HEADERS  += mainwindow.h
FORMS    += mainwindow.ui

Application output:

Starting /home/paul/store/c++/build-project-QT5_6_1-Debug/project...
libva info: VA-API version 0.39.2
libva info: va_getDriverName() returns 0
libva info: Trying to open /usr/lib64/va/drivers/i965_drv_video.so
libva info: Found init function __vaDriverInit_0_39
libva info: va_openDriver() returns 0
QMediaPlayer::PlayingState
/home/paul/store/c++/build-project-QT5_6_1-Debug/projectexited with code 0

gst-inspect-1.0 | grep 264 :

libav:  avdec_h264: libav H.264 / AVC / MPEG-4 AVC / MPEG-4 part 10 decoder
libav:  avmux_ipod: libav iPod H.264 MP4 (MPEG-4 Part 14) muxer
videoparsersbad:  h264parse: H.264 parser
x264:  x264enc: x264enc
vaapiparse:  vaapiparse_h264: H.264 parser
vaapi:  vaapiencode_h264: VA-API H.264 encoder
typefindfunctions: video/x-h264: h264, x264, 264
rtp:  rtph264depay: RTP H264 depayloader
rtp:  rtph264pay: RTP H264 payloader

any ideas?

pauledd

problem solved (so far) by uninstalling the gst-plugins-vaapi-0.7.0. Videofile plays now correctly.

? Offline

@pauledd Hi! Please mark your threads as solved by using the "topic tools" button instead of adding [solved] or something to the title, as described here: http://forum.qt.io/topic/62700/hitchhiker-s-visual-guide-to-the-qt-forum.
Cheers!

Dilip122

I am having exactly the same issue but I could not found any gst-plugins-vaapi.
Please help being specific.Thanks.

Dilip122

I tried to remove gst-vaapi. Now the video plays but it is not hardware accelerated. I mean cpu usage is high now as compared to the command-line playback using gst-launch-1.0.
I need hardware acceleration as well.

chris_m

Don't think this is solved, uninstalling gst-plugins-vaapi is a workaround at best.

Bug:
Qt Multimedia GStreamer backend doesn't support HW-accelerated video decoding
https://bugreports.qt.io/browse/QTBUG-23761