Cross compile VLC for ARM-based platform

Cross compile VLC for ARM-based platforms
Last updated: v0.0.2, 19 march 2004
This document describes all the steps to cross compile vlc for ARM based platforms. It describes how to build a cross compilation toolchain, how to build the libraries needed by vlc and the compilation of the vlc itself.

Introduction
This document is only a first draft. It does not intend to cover all subjects and is written for vlc version 0.7.2. You may still have some problems at some steps or find better way to do them. If you have any comment do not hesitate to contact us.

Which platforms are targeted ?
I will describe here how to compile vlc for an ARM based PDA running linux. It includes for example :

Compaq - iPaq (H36xx, H38xx,...), using Familiar Linux
GNU Portable Environment (GPE)
Opie
YOPY/Linupy
Zaurus

Requirements for cross-compilation
Why cross-compiling ?
It is of course possible to compile directly on the targeted platform. But there are a lot of great advantages to cross-compile :

The most important one is probably the speed, because a desktop computer is most of the time faster than a PDA for compilation.
Another big problem is that a complete compilation toolchain does take a great amount of disk space. And this space is usually very limited on embedded systems.
And there also may not be enough memory to compile big files.

Building the toolchain
Prerequisite
Importants paths
During this section, we will use the following paths :

I would personally advise to compile everything as a normal user and then install everything as root.

${SRCDIR}
This is where the sources will be located and where the compilation will be done. (eg: /usr/src or /home/foobar/arm-src).

${PREFIX}
This is where you want to install your cross compilation toolchain. It can be either installed system-wide (in /usr/local/arm/2.95.3 for example). Installation steps (i.e. make install) will have to be done as root. Or it can be installed in user-land, for the user''s own use (/home/foobar/arm/2.95.3 for example). In this paper, the chosen prefix is /usr/local/arm/2.95.3, you will have to adapt the commands to what you choose..

Files needed
Download the following files and put them in the ${SRCDIR}. Most of them are available on the "VideoLAN website"

binutils-2.11.2.tar.gz
linux-2.4.19.tar.bz2
patch-2.4.19-rmk4.bz2
gcc-2.95.3.tar.gz
gcc-2.95.3.diff.bz2
gcc-2.95.3.diffbis.bz2
gcc-2.95.3.diff2
glibc-2.2.5.tar.gz
glibc-linuxthreads-2.2.5.tar.gz
SDL-1.2.5.tar.gz
glib-1.2.10.tar.gz
ffmpeg.tar.gz
mad-0.14.2b.tar.gz
flac-1.1.0.tar.gz
libdvbpsi-0.1.2.tar.gz
a52dec-0.7.4.tar.gz

Binutils
Compiling binutils is pretty simple :
tar -xzf binutils-2.11.2.tar.gz
cd binutils-2.11.2
./configure --target=arm-linux --prefix=/usr/local/arm/2.95.3
make
make install





Preparing linux kernel
Before building the glibc library the right kernel header files should be available. Therefor the kernel that is going to be used needs to be prepared so all necessary header files are present. Follow these steps.
tar -xzf linux-2.4.19.tar.bz2
bunzip2 patch-2.4.19-rmk4.bz2
cd linux-2.4.19
make mrproper
patch -p1 < ../patch-2.4.19-rmk4.bz2
make clean ARCH=arm CROSS_COMPILE=arm-linux-
make ARCH=arm h3600_config


Do not forget to save the configuration even if no changes are made !
make ARCH=arm menuconfig
make symlinks ARCH=arm CROSS_COMPILE=arm-linux-
mkdir -p /usr/local/arm/2.95.3/arm-linux/include
cp -Rf include/asm include/asm-arm include/linux \
/usr/local/arm/2.95.3/arm-linux/include
cd /usr/local/arm/2.95.3/arm-linux
ln -s include sys-linux




Basic cross compiler (gcc)
tar -xvzf gcc-2.95.3.tar.gz
bunzip2 gcc-2.95.3.diff.bz2
bunzip2 gcc-2.95.3.diffbis.bz2
patch -p1 -d gcc-2.95.3 < gcc-2.95.3.diff
patch -p1 -d gcc-2.95.3 < gcc-2.95.3.diffbis
cd gcc-2.95.3
./configure --target=arm-linux --disable-threads --enable-languages=c \
--prefix=/usr/local/arm/2.95.3 --with-headers=linux-2.4.19/include
make
make install



Compiling glibc
Depending on your target, you may choose another glibc version (eg: 2.1.3 for linupy 1.4)
tar -xvzf glibc-2.2.5.tar.gz
cd glibc-2.2.5
tar -xvzf ../glibc-linuxthreads-2.2.5.tar.gz
CC=arm-linux-gcc ./configure arm-linux --target=arm-linux \
--prefix=/usr/local/arm/2.95.3/arm-linux --enable-add-ons


The following step takes quite a long time!
CC=arm-linux-gcc make

If you have problems compiling glibc due to pread/pwrite, edit sysdeps/unix/sysv/linux/kernel-features.h and turn __ASSUME_PREAD_SYSCALL and __ASSUME_PWRITE_SYSCALL from 1 to 0.
CC=arm-linux-gcc make install



Full cross compiler (gcc)
Now it is time to build a cross-compiler that can built user space libraries too. Follow these steps:
rm -Rf gcc-2.95.3
tar -xvzf gcc-2.95.3.tar.gz
patch -p1 -d gcc-2.95.3 < gcc-2.95.3.diff
patch -p1 -d gcc-2.95.3 < gcc-2.95.3.diff2
cd gcc-2.95.3
./configure --target=arm-linux --prefix=/usr/local/arm/2.95.3
make
make install



Misc
Add /usr/local/arm/2.95.3/bin to your PATH. Add the following line (depends on your shell) to your shell''s configuration file :
export PATH=/usr/local/arm/2.95.3/bin:$PATH

I would advise you to completely log out and then log in again, so that the change would be taken into account. You can now check that when you type arm-linux-gcc, it launches the cross-compiler.

Next are some packages that you may compile by yourself, but I found it was easier to use the precompiled packages. You can take them at "ipkgfind">. You may find packages with other version numbers which should not be a problem.

libgcc1_3.1.1-1_arm.ipk This provides libgcc.so.1 which is needed to compile some libraries.
xlibs_4.1-5_arm.ipk, xlibs-dev_4.1.0-16_arm.ipk Those are the libraries ans the development files for X windows.
zlib1g_1.1.4-3_arm.ipk, zlib1g-dev_1.1.3-fam1_arm.ipk These libraries are needed by some libraries to compile.
Install these packages on your compiler box in /usr/local/arm/2.95.3/arm-linux : You can use the script install.sh :
#!/bin/sh
# script to install .ipk into the arm-toolchain
# usage : ./install.sh foobar.ipk

if ! tar -xvzf $1 2> /dev/null
then
ar xv $1 2> /dev/null
fi
cp data.tar.gz /usr/local/arm/2.95.3/arm-linux
cd /usr/local/arm/2.95.3/arm-linux
tar -xvzf data.tar.gz



Setting up Opie cross-compile environment
Download the Opie SDK from the website "OPIE website" using the menuitem "Download Opie SDK" or try the direct link here: "Download Opie SDK". Download all files to your ${SOURCES}/opie directory.

Opie SDK
The Opie SDK does not come with a README file or installation instructions. I give them here instead. There are two tar files in the download a OpieSDK.tar.gz2 and a kdevelop_src.tar.bz2. The last file is a modified kdevelop for use with the OpieSDK. In this tutorial we will not use that. Unpack OpieSDK.tar.bz2 in your sources cd ${SOURCES}/opie directory.
cd ${SOURCES}/opie
tar -xjvf OpieSdk.tar.bz2


It creates a directories structure ${SOURCES}/opie/opt/OpieSDK. Inside that directory a script is present to start_kdevelop. Modify this script so that it uses the correct paths for you setup.
#!/bin/sh
source ${SOURCES}/opie/opt/OpieSdk/dev_env

export KDEDIR=${SOURCES}/opie/opt/OpieSdk/kde
export PATH=${SOURCES}/opie/opt/OpieSdk/kde/bin:$PATH
kbuildsycoca
kdevelop



Save the script. Do the same with the script arm_source
source ${SOURCES}/opie/opt/OpieSdk/dev_env
export QTDIR=$QTDIR_ARM
export OPIEDIR=$OPIEDIR_ARM


Save the script and modify the script host_source in the same manner as above.
source ${SOURCES}/opie/opt/OpieSdk/dev_env
export QTDIR=$QTDIR_NAT
export OPIEDIR=$OPIEDIR_NAT


Save the script and modify the script dev_env in the same manner as above.
export PYTHONPATH=${SOURCES}/opie/opt/OpieSdk/python/opie:${SOURCES}/opie/opt/OpieSdk/python/sip
export PATH=/usr/local/arm/2.95.3/bin:/opt/OpieSdk/host_tools:${SOURCES}/opie/opt/OpieSdk/opie/x86/qt-2.3.7/bin:$PATH
export PATH=${SOURCES}/opie/opt/OpieSdk/opie/x86/qmake:$PATH
export QTDIR_NAT=${SOURCES}/opie/opt/OpieSdk/opie/x86/qt-2.3.7
export OPIEDIR_NAT=${SOURCES}/opie/opt/OpieSdk/opie/x86/sdk
export QTDIR_ARM=${SOURCES}/opie/opt/OpieSdk/opie/arm/qt-2.3.7
export OPIEDIR_ARM=${SOURCES}/opie/opt/OpieSdk/opie/arm/sdk
export OPIE_SDK_BASE=${SOURCES}/opie/opt/OpieSdk/
export OPIE_SDK_QMAKE_BASE=${SOURCES}/opie/opt/OpieSdk/opie/x86/sdk/mkspecs/qws/
export OPIE_DOC=${SOURCES}/opie/opt/OpieSdk/apidocs

export LD_LIBRARY_PATH=${SOURCES}/opie/opt/OpieSdk/sip/lib:$OPIEDIR_NAT/lib:$QTDIR_NAT/lib:$LD_LIBRARY_PATH
export OPIE_LANGUAGES=de:en:cz:da:dk:es:fr:hu:it:ja:ko:lv:mk:nl:no:pl:pt:pt_BR:ru:sl:zh_CN:zh_TW


The symbolic linke to the tool qmake points now to the wrong place. We need to fix this symbolic link. Here is the way to do that.
cd host_tools
ln -sf ${SOURCES}/opie/opt/OpieSdk/opie/x86/sdk/qmake/qmake qmake
cd ../

Now it is time to fire up our development environment and start hacking in Opie.

Cross compiling libraries needed by vlc
Download ipaq-config.site to ${SOURCES}. When downloading source tarballs copy them to your ${SOURCES} directory. Each section is supposed to begin with cd ${SOURCES}.

SDL
It is not clean at all but did not found a better working method. Using config.site it compiles well, but when linking with vlc there are problems !

/usr/local/arm/2.95.3/arm-linux/bin should contain the cross compiler without the prefix arm-linux-.
tar -xvzf SDL-1.2.5.tar.gz
cd SDL-1.2.5
./configure --enable-release --target=arm-linux --host=arm-linux \
--disable-esd \
--prefix=/usr/local/arm/2.95.3/arm-linux/usr \
--x-includes=/usr/local/arm/2.95.3/arm-linux/usr/X11R6/include \
--x-libraries=/usr/local/arm/2.95.3/arm-linux/usr/X11R6/lib \
--disable-video-opengl

export PATH=/usr/local/arm/2.95.3/arm-linux/bin:$PATH

make && make install




Glib/GTK+
tar -xvzf glib-1.2.10.tar.gz
cd glib-1.2.10
CONFIG_SITE=../ipaq-config.site ./configure \
--prefix=/usr/local/arm/2.95.3/arm-linux/usr
make
make install
cd ..
tar -xvzf gtk+-1.2.10.tar.gz
cd gtk+-1.2.10
CONFIG_SITE=../ipaq-config.site ./configure \
--prefix=/usr/local/arm/2.95.3/arm-linux/usr --with-glib=../glib-1.2.10
make
make install



ffmpeg
tar -xvzf ffmpeg.tar.gz
cd ffmpeg
./configure --cpu=armv4l --cc=arm-linux-gcc --disable-mmx \
--prefix=/usr/local/arm/2.95.3/arm-linux/usr --enable-shared
cd libavcodec
make


Vlc does not require that you install ffmpeg.

mad
tar -xvzf mad-0.14.2b.tar.gz
cd mad-0.14.2b
./configure --enable-release --target=arm-linux --host=arm-linux \
--disable-esd \
--prefix=/usr/local/arm/2.95.3/arm-linux/usr \
--x-includes=/usr/local/arm/2.95.3/arm-linux/usr/X11R6/include \
--x-libraries=/usr/local/arm/2.95.3/arm-linux/usr/X11R6/lib \
--disable-video-opengl
export PATH=/usr/local/arm/2.95.3/arm-linux/bin:$PATH
make



gpe
Not described.

tremor
Tremor is an integer decoder for the vorbis audio codec. Download the source through CVS at the "xiph.org" website.

Log into CVS using the password : anoncvs.
cvs -d :pserver:[e-mail]:/usr/local/cvsroot login
cvs -d :pserver:[e-mail]:/usr/local/cvsroot co Tremor
cd Tremor
CONFIG_SITE=../ipaq-config.site ./configure \
--prefix=/usr/local/arm/2.95.3/arm-linux/usr
make



ogg
For ogg, it is the same as Tremor.
cvs -d :pserver:[e-mail]:/usr/local/cvsroot login
cvs -d :pserver:[e-mail]:/usr/local/cvsroot co ogg
cd ogg
CONFIG_SITE=../ipaq-config.site ./configure \
--prefix=/usr/local/arm/2.95.3/arm-linux/usr
make



flac
tar -xvzf flac-1.1.0.tar.gz
cd flac-1.1.0
./configure --enable-release --host=arm-linux --target=arm-linux \
--prefix=/usr/local/arm/2.95.3/arm-linux/usr


It will probably fail (due to the xmms plugin), but it is not a problem, we will continue installation by hand.
cp -Rf include/FLAC /usr/local/arm/2.95.3/arm-linux/include
cd src/libFLAC
make install



libdvbpsi
tar -xvzf libdvbpsi-0.1.2.tar.gz
cd libdvbpsi-0.1.2
./bootstrap
./configure --target=arm-linux --host=arm-linux
make



a52
tar -xvzf a52dec-0.7.4.tar.gz
cd a52dec-0.7.4
./configure --enable-release --host=arm-linux --target=arm-linux \
--prefix=/usr/local/arm/2.95.3/arm-linux/usr
make && make install



Cross compiling vlc itself
First of all, run the ./bootstrap script. Then run one of the ipkg/rules.*, according to what you want to compile. Finally you just have to type make and you''ll get a stand alone vlc.

Run arm-linux-strip to remove symbols and so the size of the file, and now you can test it easily on your PDA.

Enjoy !

Written by Marc Ariberti and Jean-Paul Saman, for the VideoLAN Team.