Helix YUV Codecs 1.3

Other actions performed by this codec are handling the output of AviSynth scripts and compressing video files to these formats.

The components of the Helix YUV Codecs pack are an I420 VFW Compressor/Decompressor and an YV12 VFW Compressor/Decompressor. I420 is YV12 with the chroma planes swapped.

Both tools decode I420 and YV12. They are almost identical, as they accept common input formats and provide lossless compression. The difference is that i420vfw.dll encodes to I420, while yv12vfw.dll encodes to YV12. With the Helix YUV Codecs you can obtain fast color conversions to the most popular RGB formats, YUV2 and I420 and YV12 when requested.

A limitation for these tools is that width has to be a multiple of 4, and height needs to be a multiple of 2.

VfW codecs are necessary for playing and editing in VirtualDub and other similar applications.

The aim of the Helix YUV Codecs was to provide a better alternative to MS H.263, which couldn’t handle dimension multiple of 15 or exceeding 352 x 288. On the other hand, the Helix YUV Codecs can handle multiples of 4.

Unlike XviD and MS H.263, the Helix YUV Codecs can convert both to and from I420 and YV12. The codec responsible for handling each format is selected automatically.

Changes in HelixRC3 1.2/1.3

- Modified I420 Codec for IYUV Colorspace (same as I420) and added the "iyuvvfw.dll" Codec for both Versions.
- The IYUV Codec stays now in 12 Bit and does not upscale to YUY2 anymore to other 12 Bit Codecs.
- The IYUV Codec now reports itself as "Helix IYUV 420 Codec" instead of "Helix IYUV YUV Codec".
- Fixed decoding Intel I420/IYUV Videos (32/64 Bit) with the Helix Codecs and works both ways now for encoding and decoding.
- Fixed decoding Drastic YCbCr I420/IYUV/YV12 Videos (32 Bit) with the Helix Codecs and works both ways now for encoding and decoding.
- Fixed decoding Arksoft IYUV and ATI YV12 Videos (32/64 Bit) with the Helix Codecs for encoding and decoding.
- Fixed Problems with Empia/Afa/SynTek and other Capture Drivers.
- Fixed Problems with Osprey/ATI/Matrox/Intel/Aurora/DVS and other popular Videoboards.
- Solved minor Problems with HonesTech HDV Encoder, MainConcept, Craaft Cinema, Cinegy, Microsoft and Pegasus encoders.
- Solved Problems with the FourCC Codec install Order in the Registry.
- Solved Problems with DirectX, Direct Draw, Active Movie, Direct2D, Direct3D and OpenGL FourCC Mapping from I420 to IYUV. (Conforms now to the Microsoft White Paper for YUV Formats in Windows)
- The new INF- File restores the native 32 Bit Windows Codecs if the Helix Codecs are uninstalled and removed from the System.
- Other 64 Bit Codecs for I420/IYUV/YV12 are no longer replaced by the Helix Codecs and can co- exist now with the Helix Codecs.

These codecs are very helpful for those using older machines and older versions of codecs and media players.