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OpenH264
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========
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=======
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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.
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Encoder Features
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------------------------
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- Constrained Baseline Profile up to Level 5.2 (4096x2304)
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- Arbitrary resolution, not constrained to multiples of 16x16
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- Rate control with adaptive quantization, or constant quantization
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- Slice options: 1 slice per frame, N slices per frame, N macroblocks per slice, or N bytes per slice
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- Multiple threads automatically used for multiple slices
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- Temporal scalability up to 4 layers in a dyadic hierarchy
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- Spatial simulcast up to 4 resolutions from a single input
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- Long Term Reference (LTR) frames
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- Memory Management Control Operation (MMCO)
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- Reference picture list modification
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- Single reference frame for inter prediction
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- Multiple reference frames when using LTR and/or 3-4 temporal layers
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- Periodic and on-demand Instantaneous Decoder Refresh (IDR) frame insertion
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- Dynamic changes to bit rate, frame rate, and resolution
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- Annex B byte stream output
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- YUV 4:2:0 planar input
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Decoder Features
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------------------------
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- Constrained Baseline Profile up to Level 5.2 (4096x2304)
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- Arbitrary resolution, not constrained to multiples of 16x16
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- Single thread for all slices
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- Long Term Reference (LTR) frames
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- Memory Management Control Operation (MMCO)
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- Reference picture list modification
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- Multiple reference frames when specified in Sequence Parameter Set (SPS)
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- Annex B byte stream input
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- YUV 4:2:0 planar output
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OS Support
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----------------
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- Windows 64-bit and 32-bit (initial release is only 32-bit, 64-bit will follow soon)
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- Mac OS X 64-bit (initial release does not include this target, will follow soon)
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- Linux 64-bit and 32-bit (initial release is only 32-bit, 64-bit will follow soon)
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- Android 32-bit (initial release does not include this target, will follow soon)
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- iOS 64-bit and 32-bit (not supported yet, may be added in the future)
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Processor Support
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-------------------------
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- Intel x86 optionally with MMX/SSE (no AVX yet, help is welcome)
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- ARMv7 optionally with NEON (initial release does not include this target, will follow later)
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- Any architecture using C/C++ fallback functions
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This goal of this project is to build a BSD-licensed open source H.264
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codec that is suitable for use in real time applications such as WebRTC. See
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http://www.openh264.org/ for more details.
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This repo has no codec code yet (only the code for the website, in the gh-pages
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branch). The code exists, and is used internally in Cisco products. But before
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we can release it and start the public project, we need to do the following
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things:
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* Separate the code from its dependencies on Cisco source code which is not
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intended to be open sourced;
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* Check that we won't 0-day other Cisco products by releasing code which
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has known unpublished security vulnerabilities;
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* Make sure all the legal processes necessary before opening code have been
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completed.
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We hope to have these steps completed soon.
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Using the Library
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-----------------------
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Linux makefiles for 32 bit builds are available:
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: build the decoder library and executable via codec/build/linux/dec/makefile
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: build the encoder library and executable via codec/build/linux/enc/makefile
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: build the encoder shared library via processing/build/linux/makefile
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Windows Visual Studio 2008/2010/2012 projects are available:
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: build the decoder via the Visual Studio projects in codec/build/win32/dec
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: build the encoder via the Visual Studio projects in codec/build/win32/dec
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: build the encoder shared library via the Visual Studio projects in processing/build/win32/
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NASM needed to be installed for assembly code: workable version 2.07 or above, nasm can downloaded from http://www.nasm.us/
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API details to be provided later.
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Using the Test App
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-------------------------
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Linux shell scripts to build the test apps:
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: build via testbin/AutoBuild_Linux.sh
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: clean via testbin/AutoClean_Linux.sh
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Windows batch files to build the test apps:
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: Visual Studio 2008 use testbin/AutoBuild_Windows_VS2008.bat
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: Visual Studio 2010 use testbin/AutoBuild_Windows_VS2010.bat
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: Visual Studio 2012 use testbin/AutoBuild_Windows_VS2012.bat
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Usage information can be found in testbin/CmdLineReadMe
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Command line options and details to be provided later.
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Using the Source
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-----------------------
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codec - encoder, decoder, console (test app), build (makefile, vcproj)
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processing - raw pixel processing (used by encoder)
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testbin - autobuild scripts, test app config files, yuv test files
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bin - binaries for library and test app
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Known Issues
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-------------------
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See the issue tracker on https://github.com/cisco/openh264/issues
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- Encoder errors when resolution exceeds 3840x2160
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- Encoder errors when compressed frame size exceeds half uncompressed size
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- Encoder console app only support multiple of 16 width/height for now
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- Decoder errors when compressed frame size exceeds 1MB
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License
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----------
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BSD, see LICENSE file for details.
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