OpenH264
OpenH264 is a codec library which supports H.264 encoding and decoding. It is suitable for use in real time applications such as WebRTC. See http://www.openh264.org/ for more details.
Encoder Features
- Constrained Baseline Profile up to Level 5.2 (Max frame size is 36864 macro-blocks)
- Arbitrary resolution, not constrained to multiples of 16x16
- Rate control with adaptive quantization, or constant quantization
- Slice options: 1 slice per frame, N slices per frame, N macroblocks per slice, or N bytes per slice
- Multiple threads automatically used for multiple slices
- Temporal scalability up to 4 layers in a dyadic hierarchy
- Simulcast AVC up to 4 resolutions from a single input
- Spatial simulcast up to 4 resolutions from a single input
- Long Term Reference (LTR) frames
- Memory Management Control Operation (MMCO)
- Reference picture list modification
- Single reference frame for inter prediction
- Multiple reference frames when using LTR and/or 3-4 temporal layers
- Periodic and on-demand Instantaneous Decoder Refresh (IDR) frame insertion
- Dynamic changes to bit rate, frame rate, and resolution
- Annex B byte stream output
- YUV 4:2:0 planar input
Decoder Features
- Constrained Baseline Profile up to Level 5.2 (Max frame size is 36864 macro-blocks)
- Arbitrary resolution, not constrained to multiples of 16x16
- Single thread for all slices
- Long Term Reference (LTR) frames
- Memory Management Control Operation (MMCO)
- Reference picture list modification
- Multiple reference frames when specified in Sequence Parameter Set (SPS)
- Annex B byte stream input
- YUV 4:2:0 planar output
OS Support
- Windows 64-bit and 32-bit
- Mac OS X 64-bit and 32-bit
- Mac OS X ARM64
- Linux 64-bit and 32-bit
- Android 64-bit and 32-bit
- iOS 64-bit and 32-bit
- Windows Phone 32-bit
Architectures verified to be working
- ppc64el
Processor Support
- Intel x86 optionally with MMX/SSE (no AVX yet, help is welcome)
- ARMv7 optionally with NEON, AArch64 optionally with NEON
- Any architecture using C/C++ fallback functions
Building the Library
NASM needed to be installed for assembly code: workable version 2.10.06 or above, NASM can be downloaded from http://www.nasm.us/. For Mac OSX 64-bit NASM needed to be below version 2.11.08 as NASM 2.11.08 will introduce error when using RIP-relative addresses in Mac OSX 64-bit
To build the arm assembly for Windows Phone, gas-preprocessor is required. It can be downloaded from git://git.libav.org/gas-preprocessor.git
For Android Builds
To build for android platform, You need to install android sdk and ndk. You also need to export **ANDROID_SDK**/tools
to PATH. On Linux, this can be done by
export PATH=**ANDROID_SDK**/tools:$PATH
The codec and demo can be built by
make OS=android NDKROOT=**ANDROID_NDK** TARGET=**ANDROID_TARGET**
Valid **ANDROID_TARGET**
can be found in **ANDROID_SDK**/platforms
, such as android-12
.
You can also set ARCH
, NDKLEVEL
according to your device and NDK version.
ARCH
specifies the architecture of android device. Currently arm
, arm64
, x86
and x86_64
are supported, the default is arm
. (mips
and mips64
can also be used, but there's no specific optimization for those architectures.)
NDKLEVEL
specifies android api level, the default is 12. Available possibilities can be found in **ANDROID_NDK**/platforms
, such as android-21
(strip away the android-
prefix).
By default these commands build for the armeabi-v7a
ABI. To build for the other android
ABIs, add ARCH=arm64
, ARCH=x86
, ARCH=x86_64
, ARCH=mips
or ARCH=mips64
.
To build for the older armeabi
ABI (which has armv5te as baseline), add APP_ABI=armeabi
(ARCH=arm
is implicit).
To build for 64-bit ABI, such as arm64
, explicitly set NDKLEVEL
to 21 or higher.
For iOS Builds
You can build the libraries and demo applications using xcode project files
located in codec/build/iOS/dec
and codec/build/iOS/enc
.
You can also build the libraries (but not the demo applications) using the make based build system from the command line. Build with
make OS=ios ARCH=**ARCH**
Valid values for **ARCH**
are the normal iOS architecture names such as
armv7
, armv7s
, arm64
, and i386
and x86_64
for the simulator.
Another settable iOS specific parameter
is SDK_MIN
, specifying the minimum deployment target for the built library.
For other details on building using make on the command line, see
'For All Platforms' below.
For Linux Builds
You can build the libraries (but not the demo applications) using the make based build system from the command line. Build with
make OS=linux ARCH=**ARCH**
You can set ARCH
according to your linux device .
ARCH
specifies the architecture of the device. Currently arm
, arm64
, x86
and x86_64
are supported
NOTICE: If your computer is x86 architecture, for build the libnary which be used on arm/aarch64 machine, you may need to use cross-compiler, for example: make OS=linux CC=aarch64-linux-gnu-gcc CXX=aarch64-linux-gnu-g++ ARCH=arm64 or make OS=linux CC=arm-linux-gnueabi-gcc CXX=arm-linux-gnueabi-g++ ARCH=arm
For Windows Builds
"make" must be installed. It is recommended to install the Cygwin and "make" must be selected to be included in the installation. After the installation, please add the Cygwin bin path to your PATH.
openh264/build/AutoBuildForWindows.bat is provided to help compile the libraries on Windows platform.
Usage of the .bat script:
`AutoBuildForWindows.bat Win32-Release-ASM` for x86 Release build
`AutoBuildForWindows.bat Win64-Release-ASM` for x86_64 Release build
`AutoBuildForWindows.bat ARM64-Release-ASM` for arm64 release build
for more usage, please refer to the .bat script help.
For All Platforms
Using make
From the main project directory:
make
for automatically detecting architecture and building accordinglymake ARCH=i386
for x86 32-bit buildsmake ARCH=x86_64
for x86 64-bit buildsmake ARCH=arm64
for arm64 Mac 64-bit buildsmake V=No
for a silent build (not showing the actual compiler commands)make DEBUGSYMBOLS=True
for two libraries, one is normal libraries, another one is removed the debugging symbol table entries (those created by the -g option)
The command line programs h264enc
and h264dec
will appear in the main project directory.
A shell script to run the command-line apps is in testbin/CmdLineExample.sh
Usage information can be found in testbin/CmdLineReadMe
Using meson
Meson build definitions have been added, and are known to work on Linux and Windows, for x86 and x86 64-bit.
See http://mesonbuild.com/Installing.html for instructions on how to install meson, then:
meson builddir
ninja -C builddir
Run the tests with:
meson test -C builddir -v
Install with:
ninja -C builddir install
Using the Source
codec
- encoder, decoder, console (test app), build (makefile, vcproj)build
- scripts for Makefile build systemtest
- GTest unittest filestestbin
- autobuild scripts, test app config filesres
- yuv and bitstream test files
Known Issues
See the issue tracker on https://github.com/cisco/openh264/issues
- Encoder errors when resolution exceeds 3840x2160
- Encoder errors when compressed frame size exceeds half uncompressed size
- Decoder errors when compressed frame size exceeds 1MB
- Encoder RC requires frame skipping to be enabled to hit the target bitrate, if frame skipping is disabled the target bitrate may be exceeded
License
BSD, see LICENSE
file for details.