Free video codec software for windows

The code is written from scratch by Laurent Aimar, Loren Merritt, Eric Petit(OS X), Min Chen (vfw/asm), Justin Clay(vfw), M?ns Rullg?rd, Christian Heine (asm), and Alex Izvorski (asm).
Note: x264 is still considered alpha, so errors can (and will) occur!

Main features:
- CAVLC/CABAC
- Multi-references
- Intra: all macroblock types (16x16, 8x8, and 4x4 with all predictions)
- Inter P: all partitions (from 16x16 down to 4x4)
- Inter B: partitions from 16x16 down to 8x8 (including skip/direct)
- Ratecontrol: optional VBV, single or multipass ABR, constant quantizer
- Scene cut detection
- Adaptive B-frame placement
- B-frames as references / arbitrary frame order
- 8x8 and 4x4 adaptive spatial transform
- Lossless mode
- Custom quantization matrices
- Parallel encoding of multiple slices
- Interlacing

Enhancements:
- Disable I_PCM with psy-RD
- psy-RD seems to put the PCM threshold a bit lower than it should be, so PCM is now disabled under psy-RD

The code is written from scratch by Laurent Aimar, Loren Merritt, Eric Petit(OS X), Min Chen (vfw/asm), Justin Clay(vfw), M?ns Rullg?rd, Christian Heine (asm), and Alex Izvorski (asm).
Note: x264 is still considered alpha, so errors can (and will) occur!

Main features:
- CAVLC/CABAC
- Multi-references
- Intra: all macroblock types (16x16, 8x8, and 4x4 with all predictions)
- Inter P: all partitions (from 16x16 down to 4x4)
- Inter B: partitions from 16x16 down to 8x8 (including skip/direct)
- Ratecontrol: optional VBV, single or multipass ABR, constant quantizer
- Scene cut detection
- Adaptive B-frame placement
- B-frames as references / arbitrary frame order
- 8x8 and 4x4 adaptive spatial transform
- Lossless mode
- Custom quantization matrices
- Parallel encoding of multiple slices
- Interlacing

Enhancements:
- Check whether echo -n works, otherwise try printf (fixes build on current OS X 10.5)

The code is written from scratch by Laurent Aimar, Loren Merritt, Eric Petit(OS X), Min Chen (vfw/asm), Justin Clay(vfw), M?ns Rullg?rd, Christian Heine (asm), and Alex Izvorski (asm).
Note: x264 is still considered alpha, so errors can (and will) occur!

Main features:
- CAVLC/CABAC
- Multi-references
- Intra: all macroblock types (16x16, 8x8, and 4x4 with all predictions)
- Inter P: all partitions (from 16x16 down to 4x4)
- Inter B: partitions from 16x16 down to 8x8 (including skip/direct)
- Ratecontrol: optional VBV, single or multipass ABR, constant quantizer
- Scene cut detection
- Adaptive B-frame placement
- B-frames as references / arbitrary frame order
- 8x8 and 4x4 adaptive spatial transform
- Lossless mode
- Custom quantization matrices
- Parallel encoding of multiple slices
- Interlacing

Enhancements:
- Replace High 4:4:4 profile lossless with High 4:4:4 Predictive. This improves lossless compression by about 4-25% depending on source. The benefit is generally higher for intra-only compression. Also add support for 8x8dct and i8x8 blocks in lossless mode; this improves compression very slightly. In some rare cases 8x8dct can hurt compression in lossless mode, but its usually helpful, albeit marginally. Note that 8x8dct is only available with CABAC as it is never useful with CAVLC.
- High 4:4:4 Predictive replaced the previous profile in a 2007 revision to the H.264 standard. The only known compliant decoder for this profile is the latest version of CoreAVC.