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coder, 25/04/2015 21:34
RaspberryPiSourceInstall¶
This page explains how to install the libavg developer version from github on a Raspberry Pi by cross-compiling. The process involves compiling libavg on a separate Linux machine. The benefit of this is that compiling on the Pi 2 takes around an hour, while cross-compiling takes a few minutes (The original Pi would finish in 4-6 hours or fail with an out of memory condition). The downside is that it's a bit harder to set up.
Alternatively, you can compile directly on the Pi by following the UbuntuSourceInstall directions.
Install dependencies on the Pi¶
On the Pi, install the needed packages:
$ sudo apt-get install git automake autoconf libtool libxml2-dev \
libpango1.0-dev librsvg2-dev libgdk-pixbuf2.0-dev libavcodec-dev libavformat-dev \
libswscale-dev libavresample-dev python-dev libboost-python-dev libboost-thread-dev g++ libSDL-dev \
libxxf86vm-dev libdc1394-22-dev linux-libc-dev
Set up the Cross-compile Toolchain¶
This is the directory structure on the Linux machine:
rpi libavg - the libavg source tree root - copy of the PI filesystem rpi-tools - the toolchain (compiler, linker, etc.) used to cross-compile staging - the compiled version of libavg that will be copied to the PI
On the Linux machine, download the crosscompile tools to rpi-tools:
$ cd rpi
$ git clone git://github.com/raspberrypi/tools.git
Copy /usr, /lib, and /opt/vc directory trees from the Pi (replace $PI with the IP address of the Pi):
$ mkdir root
$ cd root
$ rsync -rl --delete-after --safe-links pi@$PI:/{lib,usr} .
$ rsync -rl --delete-after --safe-links pi@192.168.2.PI:/opt/vc opt
Then, fix some system libraries so they don't contain references to absolute directories. Open the files in a text editor and change them. They are:
root/usr/lib/arm-linux-gnueabihf/libpthread.so:
OUTPUT_FORMAT(elf32-littlearm)
GROUP ( libpthread.so.0 libpthread_nonshared.a )
root/usr/lib/arm-linux-gnueabihf/libc.so:
OUTPUT_FORMAT(elf32-littlearm)
GROUP ( libc.so.6 libc_nonshared.a AS_NEEDED ( ld-linux-armhf.so.3 ) )
Fix some symlinks:
$ cd root/usr/lib/arm-linux-gnueabihf/
$ ln -s ../../../lib/arm-linux-gnueabihf/libm.so.6 libm.so
$ ln -s ../../../lib/arm-linux-gnueabihf/libdl.so.2 libdl.so
Put the toolchain into the path ($RPI is the absolute path to your rpi directory):
$ export PATH=$PATH:$RPI/rpi-tools/arm-bcm2708/gcc-linaro-arm-linux-gnueabihf-raspbian-x64/bin
Build libavg¶
Tell configure which architecture to build for. For Raspbian on the Pi 2:
$ export ARCHFLAGS="-mcpu=cortex-a7 -mfpu=neon-vfpv4"
and for the older Pi:
$ export ARCHFLAGS="-march=armv6 -mfloat-abi=hard -mfpu=vfp"
for other distros, run gcc -mcpu=native -march=native -Q --help=target
on the Pi
to find out what to set ARCHFLAGS to.
Once you've set the architecture, build:
$ ./rpi-configure
$ DESTDIR=$RPI/staging make -j6
$ DESTDIR=$RPI/staging make install
Install on the Pi¶
Copy the compiled libavg to the Pi:
$ cd staging
$ rsync -au usr pi@$IP:/home/pi/Desktop
On the Pi, copy libavg from the desktop to its final destination:
$ sudo cp -R ~/Desktop/usr/* /usr
Run the tests¶
$ cd /usr/local/share/python-libavg/test/
$ python Test.py
That's it! libavg should now be running on your Pi.