Ecosyste.ms: Awesome

An open API service indexing awesome lists of open source software.

Awesome Lists | Featured Topics | Projects

https://github.com/webmproject/libvpx

Mirror only. Please do not send pull requests.
https://github.com/webmproject/libvpx

Last synced: 18 days ago
JSON representation

Mirror only. Please do not send pull requests.

Awesome Lists containing this project

README 

        
Welcome to the WebM VP8/VP9 Codec SDK!



COMPILING THE APPLICATIONS/LIBRARIES:

  The build system used is similar to autotools. Building generally consists of

  "configuring" with your desired build options, then using GNU make to build

  the application.



  1. Prerequisites



    * All x86 targets require the Yasm[1] assembler be installed[2].

    * All Windows builds require that Cygwin[3] or MSYS2[4] be installed.

    * Building the documentation requires Doxygen[5]. If you do not

      have this package, the install-docs option will be disabled.

    * Downloading the data for the unit tests requires curl[6] and sha1sum.

      sha1sum is provided via the GNU coreutils, installed by default on

      many *nix platforms, as well as MinGW and Cygwin. If coreutils is not

      available, a compatible version of sha1sum can be built from

      source[7]. These requirements are optional if not running the unit

      tests.



    [1]: http://www.tortall.net/projects/yasm

    [2]: For Visual Studio the base yasm binary (not vsyasm) should be in the

         PATH for Visual Studio. For VS2017 it is sufficient to rename

         yasm--.exe to yasm.exe and place it in:

         Program Files (x86)/Microsoft Visual Studio/2017//Common7/Tools/

    [3]: http://www.cygwin.com

    [4]: http://www.msys2.org/

    [5]: http://www.doxygen.org

    [6]: http://curl.haxx.se

    [7]: http://www.microbrew.org/tools/md5sha1sum/



  2. Out-of-tree builds

  Out of tree builds are a supported method of building the application. For

  an out of tree build, the source tree is kept separate from the object

  files produced during compilation. For instance:



    $ mkdir build

    $ cd build

    $ ../libvpx/configure 

    $ make



  3. Configuration options

  The 'configure' script supports a number of options. The --help option can be

  used to get a list of supported options:

    $ ../libvpx/configure --help



  4. Compiler analyzers

  Compilers have added sanitizers which instrument binaries with information

  about address calculation, memory usage, threading, undefined behavior, and

  other common errors. To simplify building libvpx with some of these features

  use tools/set_analyzer_env.sh before running configure. It will set the

  compiler and necessary flags for building as well as environment variables

  read by the analyzer when testing the binaries.

    $ source ../libvpx/tools/set_analyzer_env.sh address



  5. Cross development

  For cross development, the most notable option is the --target option. The

  most up-to-date list of supported targets can be found at the bottom of the

  --help output of the configure script. As of this writing, the list of

  available targets is:



    arm64-android-gcc

    arm64-darwin-gcc

    arm64-darwin20-gcc

    arm64-darwin21-gcc

    arm64-darwin22-gcc

    arm64-darwin23-gcc

    arm64-linux-gcc

    arm64-win64-gcc

    arm64-win64-vs15

    arm64-win64-vs16

    arm64-win64-vs16-clangcl

    arm64-win64-vs17

    arm64-win64-vs17-clangcl

    armv7-android-gcc

    armv7-darwin-gcc

    armv7-linux-rvct

    armv7-linux-gcc

    armv7-none-rvct

    armv7-win32-gcc

    armv7-win32-vs14

    armv7-win32-vs15

    armv7-win32-vs16

    armv7-win32-vs17

    armv7s-darwin-gcc

    armv8-linux-gcc

    loongarch32-linux-gcc

    loongarch64-linux-gcc

    mips32-linux-gcc

    mips64-linux-gcc

    ppc64le-linux-gcc

    sparc-solaris-gcc

    x86-android-gcc

    x86-darwin8-gcc

    x86-darwin8-icc

    x86-darwin9-gcc

    x86-darwin9-icc

    x86-darwin10-gcc

    x86-darwin11-gcc

    x86-darwin12-gcc

    x86-darwin13-gcc

    x86-darwin14-gcc

    x86-darwin15-gcc

    x86-darwin16-gcc

    x86-darwin17-gcc

    x86-iphonesimulator-gcc

    x86-linux-gcc

    x86-linux-icc

    x86-os2-gcc

    x86-solaris-gcc

    x86-win32-gcc

    x86-win32-vs14

    x86-win32-vs15

    x86-win32-vs16

    x86-win32-vs17

    x86_64-android-gcc

    x86_64-darwin9-gcc

    x86_64-darwin10-gcc

    x86_64-darwin11-gcc

    x86_64-darwin12-gcc

    x86_64-darwin13-gcc

    x86_64-darwin14-gcc

    x86_64-darwin15-gcc

    x86_64-darwin16-gcc

    x86_64-darwin17-gcc

    x86_64-darwin18-gcc

    x86_64-darwin19-gcc

    x86_64-darwin20-gcc

    x86_64-darwin21-gcc

    x86_64-darwin22-gcc

    x86_64-darwin23-gcc

    x86_64-iphonesimulator-gcc

    x86_64-linux-gcc

    x86_64-linux-icc

    x86_64-solaris-gcc

    x86_64-win64-gcc

    x86_64-win64-vs14

    x86_64-win64-vs15

    x86_64-win64-vs16

    x86_64-win64-vs17

    generic-gnu



  The generic-gnu target, in conjunction with the CROSS environment variable,

  can be used to cross compile architectures that aren't explicitly listed, if

  the toolchain is a cross GNU (gcc/binutils) toolchain. Other POSIX toolchains

  will likely work as well. For instance, to build using the mipsel-linux-uclibc

  toolchain, the following command could be used (note, POSIX SH syntax, adapt

  to your shell as necessary):



    $ CROSS=mipsel-linux-uclibc- ../libvpx/configure



  In addition, the executables to be invoked can be overridden by specifying the

  environment variables: AR, AS, CC, CXX, LD, STRIP. Additional flags can be

  passed to these executables with ASFLAGS, CFLAGS, CXXFLAGS, and LDFLAGS.



  6. Configuration errors

  If the configuration step fails, the first step is to look in the error log.

  This defaults to config.log. This should give a good indication of what went

  wrong. If not, contact us for support.



VP8/VP9 TEST VECTORS:

  The test vectors can be downloaded and verified using the build system after

  running configure. To specify an alternate directory the

  LIBVPX_TEST_DATA_PATH environment variable can be used.



  $ ./configure --enable-unit-tests

  $ LIBVPX_TEST_DATA_PATH=../libvpx-test-data make testdata



CODE STYLE:

  The coding style used by this project is enforced with clang-format using the

  configuration contained in the .clang-format file in the root of the

  repository.



  Before pushing changes for review you can format your code with:

  # Apply clang-format to modified .c, .h and .cc files

  $ clang-format -i --style=file \

    $(git diff --name-only --diff-filter=ACMR '*.[hc]' '*.cc')



  Check the .clang-format file for the version used to generate it if there is

  any difference between your local formatting and the review system.



  See also: http://clang.llvm.org/docs/ClangFormat.html



PROFILE GUIDED OPTIMIZATION (PGO)

  Profile Guided Optimization can be enabled for Clang builds using the

  commands:



  $ export CC=clang

  $ export CXX=clang++

  $ ../libvpx/configure  --enable-profile

  $ make



  Generate one or multiple PGO profile files by running vpxdec or vpxenc. For

  example:



  $ ./vpxdec ../vpx/out_ful/vp90-2-sintel_1280x546_tile_1x4_1257kbps.webm \

    -o - > /dev/null



  To convert and merge the raw profile files, use the llvm-profdata tool:



  $ llvm-profdata merge -o perf.profdata default_8382761441159425451_0.profraw



  Then, rebuild the project with the new profile file:



  $ make clean

  $ ../libvpx/configure --use-profile=perf.profdata

  $ make



  Note: Always use the llvm-profdata from the toolchain that is used for

  compiling the PGO-enabled binary.



  To observe the improvements from a PGO-enabled build, enable and compare the

  list of failed optimizations by using the -Rpass-missed compiler flag. For

  example, to list the failed loop vectorizations:



  $ ../libvpx/configure --use-profile=perf.profdata \

    --extra-cflags=-Rpass-missed=loop-vectorize



  For guidance on utilizing PGO files to identify potential optimization

  opportunities, see: tools/README.pgo.md



SUPPORT

  This library is an open source project supported by its community. Please

  email [email protected] for help.



BUG REPORTS

  Bug reports can be filed in the libvpx issue tracker:

  https://issues.webmproject.org/.