更改Qt输出目录和加载FFmpeg

#在Pro文件中加入以下内容
CONFIG +=c++11
#Qt中屏蔽警告和调试信息
DEFINES += QT_NO_WARNING_OUTPUT\
                        QT_NO_DEBUG_OUTPUT
build_type =
CONFIG(debug, debug|release) {
    build_type = debug
} else {
    build_type = release
}

DESTDIR = $$PWD/tmp/$$build_type/

MOC_DIR = $$PWD/tmp/moc

RCC_DIR =  $$PWD/tmp/rcc

UI_DIR =  $$PWD/tmp/ui

OBJECTS_DIR =  $$PWD/tmp/obj
INCLUDEPATH+=$$PWD/include
unix|win32: LIBS += -L$$PWD/ffmpeg/lib/ -llibavcodec.dll libavdevice.dll libavfilter.dll \
-llibavformat.dll -llibavutil.dll -llibswresample.dll -llibswscale.dll -llibpostproc.dll

INCLUDEPATH += $$PWD/ffmpeg/include
DEPENDPATH +=$$PWD/ffmpeg/include