H.264 and VC-1 are two competing video compression standards.
Overview
+VC-1H.264GoalsDesigned to offer very high image quality with excellent compression efficiencyDesigned to meet a variety of industry needs with many profiles and levels, allowing for varying compression, quality and CPU usage levels, where the lowest level is for portable devices, designed with low CPU usage in mind, while the high levels are designed with very high quality and compression efficiency in mind Example industry useSupports 4:2:0 compression / color spaceSupports studio archiving requirements with 4:4:4 color space; separate black and white (BW) video modeLicensing costs SimilarDocumentationNot free. Reference decoder, comes with external documentation.? AVC/H264 Licensing costs and terms from MPEG LA. Reference encoder and decoder free as well. Additionally, JVT & M4IF mailing lists are available where one may receive answers on AVC related questions.
Terminology All sources for the below information are from the respective specifications listed in the overview section. Feature VC-1 H.264Partition sizes16×16 and 8×8 16×16, 16×8, 8×16, 8×8, 8×4, 4×8, and 4×4 Integer transform 8×8, 4×8, 8×4, and 4×4 4×4; 8×8 available in High Profile onlyFrame Used for progressive or interlaced contentMacroblock sizes 16×16 onlyMotion vector Two dimensional vector offset from current position to reference frame Picture A field or frame Skipped macroblock No data is encoded for macroblock
Features VC-1H.264Bitstream formatssingle bit streamNAL and byte streamBitstream formatIn advanced profile, each Bitstream Data Unit has its own header.Simple and Main profile provide neither sequence nor entry point headers. SPS (sequence parameter set), PPS (picture parameters set), slice header, macroblockDeblocking filterIn-loop filter and overlap transformIn-loop onlyCABACNoOnly supported in Main and higher profilesVariable transform sizeYesOnly in High profile and aboveSliceContiguous (integer number of macroblock rows only)Contiguous or non-contiguousSub-pixel interpolation methodsbicubic, bilinear6-tap filter for half pixels; averaging for quarter pixelsVariable Length Coding YesB frame used for predicting other pictures Yes
Adoption H.264 is by far the most commonly used format for the recording, compression, and distribution of video content, used by 79% of video industry developers .
References
External links AVC/H264 Licensing costs and terms from MPEG LA EEtimes comparison of video codecs
Codec challenge comparison on Doom9 with professional VC1 encoder, PeP, and x264 for H264 => x264 win the first round Microsoft employee discusses differences between VC-1 and H.264 Comparison at Doom9