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 (4096x2304)
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
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 (4096x2304)
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 (initial release is only 32-bit, 64-bit will follow soon)
Mac OS X 64-bit (initial release does not include this target, will follow soon)
Linux 64-bit and 32-bit (initial release is only 32-bit, 64-bit will follow soon)
Android 32-bit (initial release does not include this target, will follow soon)
iOS 64-bit and 32-bit (not supported yet, may be added in the future)

Processor Support

Intel x86 optionally with MMX/SSE (no AVX yet, help is welcome)
ARMv7 optionally with NEON (initial release does not include this target, will follow later)
Any architecture using C/C++ fallback functions

Using the Library

Linux makefiles for 32 bit builds are available: : build the decoder library and executable via codec/build/linux/dec/makefile : build the encoder library and executable via codec/build/linux/enc/makefile : build the encoder shared library via processing/build/linux/makefile

Windows Visual Studio 2008/2010/2012 projects are available: : build the decoder via the Visual Studio projects in codec/build/win32/dec : build the encoder via the Visual Studio projects in codec/build/win32/enc : build the encoder shared library via the Visual Studio projects in processing/build/win32/

NASM needed to be installed for assembly code: workable version 2.07 or above, nasm can downloaded from http://www.nasm.us/

API details to be provided later.

Using the Test App

Linux shell scripts to build the test apps: : build via testbin/AutoBuild_Linux.sh : clean via testbin/AutoClean_Linux.sh

Windows batch files to build the test apps: : Visual Studio 2008 use testbin/AutoBuild_Windows_VS2008.bat : Visual Studio 2010 use testbin/AutoBuild_Windows_VS2010.bat : Visual Studio 2012 use testbin/AutoBuild_Windows_VS2012.bat

Usage information can be found in testbin/CmdLineReadMe Command line options and details to be provided later.

Using the Source

codec - encoder, decoder, console (test app), build (makefile, vcproj) processing - raw pixel processing (used by encoder) testbin - autobuild scripts, test app config files, yuv test files bin - binaries for library and test app

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
Encoder console app only support multiple of 16 width/height for now
Decoder errors when compressed frame size exceeds 1MB

License

BSD, see LICENSE file for details.

fluffy/openh264