구차니의 잡동사니 모음

 A Swedish company Coding Technologies (acquired by Dolby in 2007) developed and pioneered the use of SBR in its MPEG-2 AAC derived codec called aacPlus, which first appeared in 2001. This codec was submitted to MPEG and formed the basis of MPEG-4 High-Efficiency AAC (HE-AAC), standardized in 2003. Coding Technologies' SBR method has been used with WMA 10 Professional to create WMA 10 Pro LBR, and with MP3 to create mp3PRO.

[링크 : http://en.wikipedia.org/wiki/Spectral_band_replication]

./configure -release -opengl es2 -device linux-rasp-pi-g++ -device-option CROSS_COMPILE=$TOOLCHAIN/arm-bcm2708/gcc-linaro-arm-linux-gnueabihf-raspbian/bin/arm-linux-gnueabihf- -sysroot $ROOTFS -prefix /usr/local/qt5

./configure -platform linux-clang

./configure -platform linux-g++

./configure -platform linux-g++-32

[링크 : http://doc.qt.io/qt-5/configure-options.html]

Embedded Platforms

You can develop with Qt for the following embedded platforms:

Embedded Android

Embedded Linux

Windows Embedded (Compact and Standard)

Real-Time Operating Systems, such as QNX, VxWorks and INTEGRITY

[링크 : http://doc.qt.io/qt-5/supported-platforms.html]

./configure -release -opengl es2 -device linux-rasp-pi-g++ -device-option CROSS_COMPILE=$TOOLCHAIN/arm-bcm2708/gcc-linaro-arm-linux-gnueabihf-raspbian/bin/arm-linux-gnueabihf- -sysroot $ROOTFS -prefix /usr/local/qt5

LinuxFB

This plugin writes directly to the framebuffer. Only software-rendered content is supported. Note that on some setups the display performance is expected to be limited.

The linuxfb plugin allows specifying additional settings by passing them in the QT_QPA_PLATFORM environment variable or -platform command-line option. For example, QT_QPA_PLATFORM=linuxfb:fb=/dev/fb1 specifies that the framebuffer device /dev/fb1 should be used instead of the default fb0. Multiple settings can be specfified by separating them with a colon.

Input

When no windowing system is present, the mouse, keyboard and touch input are read directly via evdev or using helper libraries like tslib. Note that this requires that devices nodes /dev/input/event* are readable by the user. eglfs has all the evdev input handling code built-in, while linuxfb relies on the traditional and somewhat limited -plugin command-line parameters.

Input on linuxfb

To enable keyboard, mouse, touch or tablet support with linuxfb, pass QT_QPA_GENERIC_PLUGINS=evdevkeyboard,evdevmouse,evdevtouch,... in the environment or, alternatively, -plugin evdevkeyboard, -plugin evdevmouse, -plugin evdevtouch, or -plugin evdevtablet on the command-line. Most of these can take a device node parameter, for example QT_QPA_GENERIC_PLUGINS=evdevmouse:/dev/event1, in case the Qt's automatic device discovery (based either on libudev or a walkthrough of /dev/input/event*) is not functional or misbehaving.

[링크 : http://doc.qt.io/qt-5/embedded-linux.html]

-r' Recursively copy entire directories. Note that scp follows symbolic links encountered in the tree traversal.

[링크 : http://linux.die.net/man/1/scp] 

Usually, to cross-compile autotools-based packages, one do:

./configure --prefix=/usr --host=arm-linux-gnueabi

make

make DESTDIR=/embedded/target install

make DESTDIR=/embedded/staging install

You typically install things twice because in /embedded/target you want

to have only the files useful for execution, completely stripped, while

in /embedded/staging you want to keep all debugging symbols to help in

debugging. /embedded/target goes in your target embedded system,

while /embedded/staging is kept on your development machine, and is

used to build more applications and to do remote debugging.

Within Qt5, this could be translated as:

./configure -prefix /usr -device <something>

make

make INSTALL_ROOT=/embedded/target install

make INSTALL_ROOT=/embedded/staging install

But Qt5 has host utilities, not only tools for the target. And instead

of having to build Qt twice, it nicely allows to do the build of host

tools and target libraries in just one build, which is really nice. So,

one typically does:

./configure -prefix /usr -hostprefix /embedded/host -device <something>

make

make INSTALL_ROOT=/embedded/target install

make INSTALL_ROOT=/embedded/staging install

Unfortunately, the INSTALL_ROOT does not only impact target libraries,

but also the host utilities. So they end up

in /embedded/target/embedded/host which obviously isn't correct.

For the moment, I am solving this by doing:

./configure -prefix /usr -hostprefix /embedded/host -sysroot /embedded/staging -device <something>

make

make install

[링크 : http://lists.qt-project.org/pipermail/interest/2013-January/005447.html] 

-hostprefix, but it doesn't work like I hoped. With "make install INSTALL_ROOT=..." it will install everything even the host tools under this install root

[링크 : http://www.qtcentre.org/.../30449-How-to-build-and-install-Qt-apps-on-cross-compiled-embedded-targets]