HACKING.asciidoc: mention the patch needed for older libav/ffmpeg
[libam7xxx.git] / HACKING.asciidoc
1 == Hacking libam7xxx
2
3 === Coding style
4
5 libam7xxx uses the linux kernel coding style:
6 http://kernel.org/doc/Documentation/CodingStyle
7
8 === Getting and compiling libam7xxx
9
10 libam7xxx depends on 'libusb-1.0' and optionally on 'libav' or 'ffmpeg' for
11 its example programs, the build system used is 'cmake'.
12
13 On a Debian based system, the dependencies can be installed with this command:
14
15   $ sudo aptitude install cmake \
16                           libusb-1.0-0-dev \
17                           libavformat-dev \
18                           libavcodec-dev \
19                           libavdevice-dev \
20                           libswscale-dev
21
22 With libav/ffmpeg version previous than 0.9 this patch is needed:
23 http://git.ao2.it/libam7xxx.git/blob_plain/refs/heads/debian:/debian/patches/0002-Revert-am7xxx-play-switch-to-avcodec_encode_video2.patch
24
25 The library and the example programs can be compiled following these steps:
26
27   $ git clone git://git.ao2.it/libam7xxx.git
28   $ cd libam7xxx
29   $ mkdir build
30   $ cd build
31   $ cmake ../
32   $ make
33
34 After that the example programs can be found in the +bin/+ subdirectory.
35
36 === Debug builds
37
38 The suggested way to hack on the project is:
39
40   $ mkdir build
41   $ cd build
42   $ cmake -D CMAKE_BUILD_TYPE=debug -D STRICT_COMPILATION_CHECKS=ON ../
43   $ make
44
45 If you want to check the code with the ''sparse'' static analysis tool you
46 can run:
47
48   $ mkdir build
49   $ cd build
50   $ cmake -D CMAKE_C_COMPILER=cgcc ../
51   $ make
52
53 === Cross Builds
54
55 If you want to build for MS Windows:
56
57   $ sudo aptitude install mingw-w64
58   $ mkdir build
59   $ cd build
60   $ wget -nv http://sourceforge.net/projects/libusbx/files/releases/1.0.11/Windows/libusbx-1.0.11-win.7z
61   $ 7z -olibusbx-1.0.11-win x libusbx-1.0.11-win.7z
62   $ wget -nv http://win32.libav.org/win32/libav-win32-20120521.7z
63   $ 7z x libav-win32-20120521.7z
64   $ cmake  \
65           -D GNU_HOST=i686-w64-mingw32 \
66           -D CMAKE_TOOLCHAIN_FILE=../cmake_modules/mingw_cross_toolchain.cmake \
67           -D CMAKE_INSTALL_PREFIX=libam7xxx-win/ \
68           -D LIBUSB_1_INCLUDE_DIR=libusbx-1.0.11-win/include/libusbx-1.0 \
69           -D LIBUSB_1_LIBRARY=libusbx-1.0.11-win/MinGW32/dll/libusb-1.0.dll \
70           -D FFMPEG_ROOT=$(pwd)/libav-win32-20120521/usr \
71           ../
72   $ make
73
74 After that you will find libam7xxx.dll in lib/ and picoproj.exe in the bin/
75 directory.
76
77 === Valgrind
78
79 You can run the test program under the http://valgrind.org/[valgrind]
80 dynamic analyzer by using a command like:
81
82   $ valgrind --leak-check=full --show-reachable=yes --track-origins=yes \
83     ./bin/picoproj -W 800 -H 480 -f my_image.jpg