Reinstall Qt5 with QtMultimedia using Ubuntu Mate

jsulm

@Xenoshell That's what @SGaist is trying to tell you: you need to install dev packages for all multimedia components you would like to use with QtMultimedia.

Xenoshell

@jsulm yeah ok.. thanks, i am going a little bit mental here. I thought i already installed gstreamer. Thats why i was confused. I think i know now what to do

jsulm

@Xenoshell You installed GStreamer but not its development packages (which for example contain the header files). You need to install the dev packages as well.

Xenoshell

@jsulm
I installed alsa, dbus, gstreamer, ffmpeg but they still show up as errors. What can i do?

ERROR: Feature 'dbus-linked' was enabled, but the pre-condition 'features.dbus && libs.dbus' failed.

ERROR: Feature 'alsa' was enabled, but the pre-condition 'config.unix && !config.qnx && libs.alsa' failed.

ERROR: Feature 'gstreamer_1_0' was enabled, but the pre-condition 'libs.gstreamer_1_0' failed.

ERROR: Feature 'alsa' was enabled, but the pre-condition 'config.unix && libs.alsa' failed.

ERROR: Feature 'system-ffmpeg' was enabled, but the pre-condition 'libs.ffmpeg && features.system-opus && features.system-webp' failed.

jsulm

@Xenoshell What exactly did you install? You need *-dev packages.

Xenoshell

@jsulm i didnt found any -dev packages. I just searched google for packages to those features that create errors and installed those but didnt saw any -dev packages

SGaist

https://packages.ubuntu.com/artful/libgstreamer1.0-dev

Xenoshell

@SGaist ok thanks, i found all -dev packages for all the errors exept ffmpeg and dbus-linked.
./configure output is now:

Note: Also available for Linux: linux-clang linux-icc

Note: Dropped compiler flags '-pthread' when detecting library 'glib'.

Note: Disabling X11 Accessibility Bridge: D-Bus or AT-SPI is missing.

Note: Dropped compiler flags '-pthread' when detecting library 'gstreamer'.

Note: Dropped compiler flags '-pthread' when detecting library 'gstreamer_app'.

ERROR: Feature 'dbus-linked' was enabled, but the pre-condition 'features.dbus && libs.dbus' failed.

ERROR: Feature 'system-ffmpeg' was enabled, but the pre-condition 'libs.ffmpeg && features.system-opus && features.system-webp' failed.

Check config.log for details.

Do i actually need ffmpeg for qtMultimedia? Since it is a videoplayer i guess yes. I think i have to install this from source to and that could be a real pain..

SGaist

You can install libavcodec-dev and friends for ffmpeg inclusion.

As for dbus, the dbus dev package.

jsulm

@Xenoshell Why do you want to install ffmpeg from source? Install libavcodec-dev package from your Linux distribution.

Xenoshell

@SGaist i installed your suggested packages and now output is:

Note: Also available for Linux: linux-clang linux-icc

Note: Dropped compiler flags '-pthread' when detecting library 'glib'.

Note: Disabling X11 Accessibility Bridge: D-Bus or AT-SPI is missing.

Note: Dropped compiler flags '-pthread' when detecting library 'gstreamer'.

Note: Dropped compiler flags '-pthread' when detecting library 'gstreamer_app'.

ERROR: Feature 'system-ffmpeg' was enabled, but the pre-condition 'libs.ffmpeg && features.system-opus && features.system-webp' failed.

@Jsulm i dont want to install ffmpeg from source. I just installed already the package and the error still occurs and i just googled the problem and the solution was to install from source

SGaist

Check the logs for the related errors. You can also use the -v option to get a more verbose output of the configuration process.

Xenoshell

@SGaist I think i found the relevant piece of information in config.log

looking for library ffmpeg
Trying source 0 (type pkgConfig) of library ffmpeg ...
+ /usr/bin/pkg-config --exists --silence-errors libavcodec libavformat libavutil
pkg-config did not find package.
  => source produced no result.
test config.qtwebengine.libraries.ffmpeg FAILED
executing config test ninja
Building own ninja
test config.qtwebengine.tests.ninja FAILED
looking for library opus
Trying source 0 (type pkgConfig) of library opus ...
+ /usr/bin/pkg-config --exists --silence-errors opus
pkg-config did not find package.
  => source produced no result.
test config.qtwebengine.libraries.opus FAILED
executing config test re2
+ cd /home/blz/Downloads/qt-everywhere-opensource-src-5.9.3/config.tests/re2 && /home/blz/Downloads/qt-everywhere-opensource-src-5.9.3/qtbase/bin/qmake "CONFIG -= qt debug_and_release app_bundle lib_bundle" "CONFIG += shared use_gold_linker warn_off console single_arch" /home/blz/Downloads/qt-everywhere-opensource-src-5.9.3/qtwebengine/config.tests/re2
+ cd /home/blz/Downloads/qt-everywhere-opensource-src-5.9.3/config.tests/re2 && MAKEFLAGS= /usr/bin/make clean && MAKEFLAGS= /usr/bin/make
> rm -f re2.o
> rm -f *~ core *.core
> g++ -c -pipe -O2 -std=gnu++11 -w -fPIC  -I/home/blz/Downloads/qt-everywhere-opensource-src-5.9.3/qtwebengine/config.tests/re2 -I. -I/home/blz/Downloads/qt-everywhere-opensource-src-5.9.3/qtbase/mkspecs/linux-g++ -o re2.o /home/blz/Downloads/qt-everywhere-opensource-src-5.9.3/qtwebengine/config.tests/re2/re2.cpp
> /home/blz/Downloads/qt-everywhere-opensource-src-5.9.3/qtwebengine/config.tests/re2/re2.cpp:29:21: fatal error: re2/re2.h: No such file or directory
> compilation terminated.
> Makefile:1021: recipe for target 're2.o' failed
> make: *** [re2.o] Error 1
test config.qtwebengine.tests.re2 FAILED
looking for library webp
Trying source 0 (type pkgConfig) of library webp ...
+ /usr/bin/pkg-config --exists --silence-errors libwebp libwebpdemux
pkg-config did not find package.
  => source produced no result.
test config.qtwebengine.libraries.webp FAILED

SGaist

Install the libavformat and libavutil dev packages. Same goes for opus.

Xenoshell

@SGaist no error anymore. Thanks for you help. I am gonna mark this solved after i ran make and make install

Xenoshell

@SGaist
Oh well, here are some errors.. Should i be worried or not?

/usr/lib/gcc/arm-linux-gnueabihf/5/../../../arm-linux-gnueabihf/crt1.o(.text+0x28): error: undefined reference to 'main'
collect2: error: ld returned 1 exit status
Makefile:81: recipe for target 'schema' failed
make[4]: *** [schema] Error 1
make[4]: Leaving directory '/home/blz/Downloads/qt-everywhere-opensource-src-5.9.3/qtxmlpatterns/examples/xmlpatterns/schema'
Makefile:122: recipe for target 'sub-schema-make_first' failed
make[3]: *** [sub-schema-make_first] Error 2
make[3]: Leaving directory '/home/blz/Downloads/qt-everywhere-opensource-src-5.9.3/qtxmlpatterns/examples/xmlpatterns'
Makefile:44: recipe for target 'sub-xmlpatterns-make_first' failed
make[2]: *** [sub-xmlpatterns-make_first] Error 2
make[2]: Leaving directory '/home/blz/Downloads/qt-everywhere-opensource-src-5.9.3/qtxmlpatterns/examples'
Makefile:97: recipe for target 'sub-examples-make_first' failed
make[1]: *** [sub-examples-make_first] Error 2
make[1]: Leaving directory '/home/blz/Downloads/qt-everywhere-opensource-src-5.9.3/qtxmlpatterns'
Makefile:282: recipe for target 'module-qtxmlpatterns-make_first' failed
make: *** [module-qtxmlpatterns-make_first] Error 2

I am gonna not use make install just yet, because errors and wait for your answer.

JonB

@Xenoshell
Just to let you know: I am the person who tried to help with your original "why I am unable to use the camera without freezing?" question!

I see this thread is getting long, I do hope my advice to sort out your multimedia installation fully is worth it for all this compiling etc. you're doing, and not a red-herring...!!

SGaist

Don't build the tests nor the example, especially since your are cross-compiling. There's no use for that and you'll waste space, time and electricity for nothing.

Xenoshell

@SGaist So are the errors now important or can i just install without worries?
@JonB I just wanna cross out all possibilities what could be wrong

jsulm

@Xenoshell As you can see from what you posted those errors are coming from examples. As @SGaist suggested there is no need to build examples and tests (so, no these errors are not important). Use -skip to not to build examples and tests.