OpenH264 是思科公司发布的一个开源的 H.264 编码和解码器。

编码器特性

• 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

解码器特性

• 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

支持的操作系统

• 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)

支持的处理器

• 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

项目主页：http://www.open-open.com/lib/view/home/1386925096158