1 README - 9 December 2019
3 Welcome to the WebM VP8/VP9 Codec SDK!
5 COMPILING THE APPLICATIONS/LIBRARIES:
6 The build system used is similar to autotools. Building generally consists of
7 "configuring" with your desired build options, then using GNU make to build
12 * All x86 targets require the Yasm[1] assembler be installed[2].
13 * All Windows builds require that Cygwin[3] be installed.
14 * Building the documentation requires Doxygen[4]. If you do not
15 have this package, the install-docs option will be disabled.
16 * Downloading the data for the unit tests requires curl[5] and sha1sum.
17 sha1sum is provided via the GNU coreutils, installed by default on
18 many *nix platforms, as well as MinGW and Cygwin. If coreutils is not
19 available, a compatible version of sha1sum can be built from
20 source[6]. These requirements are optional if not running the unit
23 [1]: http://www.tortall.net/projects/yasm
24 [2]: For Visual Studio the base yasm binary (not vsyasm) should be in the
25 PATH for Visual Studio. For VS2017 it is sufficient to rename
26 yasm-<version>-<arch>.exe to yasm.exe and place it in:
27 Program Files (x86)/Microsoft Visual Studio/2017/<level>/Common7/Tools/
28 [3]: http://www.cygwin.com
29 [4]: http://www.doxygen.org
30 [5]: http://curl.haxx.se
31 [6]: http://www.microbrew.org/tools/md5sha1sum/
34 Out of tree builds are a supported method of building the application. For
35 an out of tree build, the source tree is kept separate from the object
36 files produced during compilation. For instance:
40 $ ../libvpx/configure <options>
43 3. Configuration options
44 The 'configure' script supports a number of options. The --help option can be
45 used to get a list of supported options:
46 $ ../libvpx/configure --help
49 Compilers have added sanitizers which instrument binaries with information
50 about address calculation, memory usage, threading, undefined behavior, and
51 other common errors. To simplify building libvpx with some of these features
52 use tools/set_analyzer_env.sh before running configure. It will set the
53 compiler and necessary flags for building as well as environment variables
54 read by the analyzer when testing the binaries.
55 $ source ../libvpx/tools/set_analyzer_env.sh address
58 For cross development, the most notable option is the --target option. The
59 most up-to-date list of supported targets can be found at the bottom of the
60 --help output of the configure script. As of this writing, the list of
95 x86-iphonesimulator-gcc
115 x86_64-iphonesimulator-gcc
125 The generic-gnu target, in conjunction with the CROSS environment variable,
126 can be used to cross compile architectures that aren't explicitly listed, if
127 the toolchain is a cross GNU (gcc/binutils) toolchain. Other POSIX toolchains
128 will likely work as well. For instance, to build using the mipsel-linux-uclibc
129 toolchain, the following command could be used (note, POSIX SH syntax, adapt
130 to your shell as necessary):
132 $ CROSS=mipsel-linux-uclibc- ../libvpx/configure
134 In addition, the executables to be invoked can be overridden by specifying the
135 environment variables: CC, AR, LD, AS, STRIP, NM. Additional flags can be
136 passed to these executables with CFLAGS, LDFLAGS, and ASFLAGS.
138 6. Configuration errors
139 If the configuration step fails, the first step is to look in the error log.
140 This defaults to config.log. This should give a good indication of what went
141 wrong. If not, contact us for support.
143 VP8/VP9 TEST VECTORS:
144 The test vectors can be downloaded and verified using the build system after
145 running configure. To specify an alternate directory the
146 LIBVPX_TEST_DATA_PATH environment variable can be used.
148 $ ./configure --enable-unit-tests
149 $ LIBVPX_TEST_DATA_PATH=../libvpx-test-data make testdata
152 The coding style used by this project is enforced with clang-format using the
153 configuration contained in the .clang-format file in the root of the
156 Before pushing changes for review you can format your code with:
157 # Apply clang-format to modified .c, .h and .cc files
158 $ clang-format -i --style=file \
159 $(git diff --name-only --diff-filter=ACMR '*.[hc]' '*.cc')
161 Check the .clang-format file for the version used to generate it if there is
162 any difference between your local formatting and the review system.
164 See also: http://clang.llvm.org/docs/ClangFormat.html
167 This library is an open source project supported by its community. Please
168 email webm-discuss@webmproject.org for help.