Showing stream video

jsulm

@BrMisha You could write your own QIODevice and use it with https://doc.qt.io/qt-5/qmediaplayer.html#setMedia

BrMisha

@jsulm I know but QMediaPlayer uses QIODevice::seek, which isn't available in stream

SGaist

Hi,

What OS are you on ?

BrMisha

@SGaist Windows (10) and Linux (Ubuntu and other).

SGaist

In that case, I would rather consider using VLC and its Qt integration to handle the video stream.

BrMisha

@SGaist but why this solution better of using system codecs?

SGaist

Because VLC is the Swiss Army Knife of vidéo decoding and supports a larger palette of codecs than most OSs provide out of the box.

BrMisha

@SGaist I would't like to use VLC but you have convinced me)))
Tomorrow i will try to build VLC for windows

SGaist

There's likely already a prebuilt package.

See also VLC-Qt

BrMisha

@SGaist is VLC-Qt still actuality now? Last commit was in 2016 year and based on VLC 2.2.4

SGaist

It does not mean it does not work anymore. I'd say it's worth a try.

BrMisha

Unfortunately, VLC doesn't provide prebuilt packages for my compiler (MinGW32-64 7.3.0).
After googling i decided to try ffmpeg. I build it following this manual https://ffmpeg.org/platform.html#Native-Windows-compilation-using-MinGW-or-MinGW_002dw64 , then add libs to *pro file:

LIBS += -LF:/FFmpeg/tempinstall/usr/local/lib/ -llibavcodec.dll -llibavformat.dll
INCLUDEPATH += F:/FFmpeg/tempinstall/usr/local/include
DEPENDPATH += F:/FFmpeg/tempinstall/usr/local/include

and i called avformat_open_input(some args). But got error^

c:/qt/qt5.14.1/tools/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/8.3.0/../../../../x86_64-w64-mingw32/bin/ld.exe: main.o: in function `qMain(int, char**)':
D:\projects_test\qt\PlayerVideo\build-PlayerVideo-Desktop-Debug/../PlayerVideo/main.cpp:58: undefined reference to `avformat_open_input(AVFormatContext**, char const*, AVInputFormat*, AVDictionary**)'

So, i'm searching my mistake... I compared compiler versions between msys2 and qt, booth have GNU Make 4.2.1, but msys2 has gcc 8.3.0 and qt has 7.3.0.
That is problem?

SGaist

It's "-lavcodec"

BrMisha

@SGaist no, it isn't helpfull((

SGaist

Did you fix all libraries name ?

BrMisha

@SGaist this part of .pro

LIBS += -LF:/Musor/FFmpeg_linbuild/ffmpeg/lib/ -lavformat

INCLUDEPATH += F:/Musor/FFmpeg_linbuild/ffmpeg/include
DEPENDPATH += F:/Musor/FFmpeg_linbuild/ffmpeg/include

In code i'm calling only avformat_license(), which locates in avformat

SGaist

Do you have ffmpeg built for the same architecture as your Qt version ?

BrMisha

@SGaist yes, booth is x64

BrMisha

Men, I really don't understand what is happening.
I installed msys2, and some packages for that, then i copied *c:\Qt\Qt5.14.2\Tools\mingw730_64* to *c:\msys64\mingw64*.
Then built libav (it is "small" version of FFmpeg) and got this files:

build\usr\local\bin\avcodec.lib
build\usr\local\bin\avcodec-58.dll
build\usr\local\bin\avconv.exe
build\usr\local\bin\avdevice.lib
build\usr\local\bin\avdevice-57.dll
build\usr\local\bin\avfilter.lib
build\usr\local\bin\avfilter-7.dll
build\usr\local\bin\avformat.lib
build\usr\local\bin\avformat-58.dll
build\usr\local\bin\avprobe.exe
build\usr\local\bin\avresample.lib
build\usr\local\bin\avresample-4.dll
build\usr\local\bin\avutil.lib
build\usr\local\bin\avutil-56.dll
build\usr\local\bin\swscale.lib
build\usr\local\bin\swscale-5.dll

build\usr\local\include\libavcodec\	<< here is *.h
build\usr\local\include\libavdevice\	<< here is *.h
build\usr\local\include\libavfilter\	<< here is *.h
build\usr\local\include\libavformat\	<< here is *.h
build\usr\local\include\libavresample\	<< here is *.h
build\usr\local\include\libavutil\	<< here is *.h
build\usr\local\include\libswscale\	<< here is *.h

build\usr\local\lib\pkgconfig\
build\usr\local\lib\avcodec-58.def
build\usr\local\lib\avdevice-57.def
build\usr\local\lib\avfilter-7.def
build\usr\local\lib\avformat-58.def
build\usr\local\lib\avresample-4.def
build\usr\local\lib\avutil-56.def
build\usr\local\lib\libavcodec.dll.a
build\usr\local\lib\libavdevice.dll.a
build\usr\local\lib\libavfilter.dll.a
build\usr\local\lib\libavformat.dll.a
build\usr\local\lib\libavresample.dll.a
build\usr\local\lib\libavutil.dll.a
build\usr\local\lib\libswscale.dll.a
build\usr\local\lib\swscale-5.def

*c:\Qt\Qt5.14.2\Tools\mingw730_64* was added to PATH. When I start, for example, avconv.exe, it works ok, so definitely libav was built with true mingw (which uses qt).
Next, i added to *.pro (using "Add library...") this:

win32: LIBS += -LF:/Musor/libav/build/usr/local/lib/ -llibavformat.dll
INCLUDEPATH += F:/Musor/libav/build/usr/local/include
DEPENDPATH += F:/Musor/libav/build/usr/local/include

main.c:

#include <libavformat/avformat.h>
int main(int argc, char *argv[]) {
	avformat_license();
	return 0;
}

After compilation i got:

C:/Qt/Qt5.14.2/Tools/mingw730_64/bin/mingw32-make -f Makefile.Debug
mingw32-make[1]: Entering directory 'D:/projects_test/qt/qt_test/build-qt_test-Desktop_Qt_5_14_2_MinGW_64_bit-Debug'
g++ -c -fno-keep-inline-dllexport -g -std=gnu++11 -Wall -Wextra -Wextra -fexceptions -mthreads -DUNICODE -D_UNICODE -DWIN32 -DMINGW_HAS_SECURE_API=1 -DQT_DEPRECATED_WARNINGS -DQT_QML_DEBUG -DQT_SERIALPORT_LIB -DQT_CORE_LIB -I..\qt_test -I. -IF:\Musor\libav\build\usr\local\include -IC:\Qt\Qt5.14.2\5.14.2\mingw73_64\include -IC:\Qt\Qt5.14.2\5.14.2\mingw73_64\include\QtSerialPort -IC:\Qt\Qt5.14.2\5.14.2\mingw73_64\include\QtCore -Idebug -IC:\Qt\Qt5.14.2\5.14.2\mingw73_64\mkspecs\win32-g++  -o debug\main.o ..\qt_test\main.cpp
..\qt_test\main.cpp: In function 'int main(int, char**)':
..\qt_test\main.cpp:4:14: warning: unused parameter 'argc' [-Wunused-parameter]
 int main(int argc, char *argv[])
              ^~~~
..\qt_test\main.cpp:4:31: warning: unused parameter 'argv' [-Wunused-parameter]
 int main(int argc, char *argv[])
                               ^
g++ -Wl,-subsystem,console -mthreads -o debug\qt_test.exe debug/main.o  -LF:\Musor\libav\build\usr\local\lib F:\Musor\libav\build\usr\local\lib\libavformat.dll.a C:\Qt\Qt5.14.2\5.14.2\mingw73_64\lib\libQt5SerialPort.a C:\Qt\Qt5.14.2\5.14.2\mingw73_64\lib\libQt5Core.a   
debug/main.o: In function `main':
D:\projects_test\qt\qt_test\build-qt_test-Desktop_Qt_5_14_2_MinGW_64_bit-Debug/../qt_test/main.cpp:6: undefined reference to `avformat_license()'
collect2.exe: error: ld returned 1 exit status
mingw32-make[1]: *** [Makefile.Debug:68: debug/qt_test.exe] Error 1
mingw32-make: *** [Makefile:45: debug] Error 2
mingw32-make[1]: Leaving directory 'D:/projects_test/qt/qt_test/build-qt_test-Desktop_Qt_5_14_2_MinGW_64_bit-Debug'
18:45:50: The process "C:\Qt\Qt5.14.2\Tools\mingw730_64\bin\mingw32-make.exe" exited with code 2.
Error while building/deploying project qt_test (kit: Desktop Qt 5.14.2 MinGW 64-bit)
When executing step "Make"

Whyyyyyyy?????
I have tried to change -llibavformat.dll to -lavformat, "-lavformat.dll" and "-lavformat" but i'm stil getting this error.

SGaist

Might be silly but try linking to all the ffmpeg libraries, just in case.