Comparison of H.264 and VC-1: Difference between revisions
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m I found one reference ineed to dig up and add, but otherwise it seems to be better now. |
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MSU Subjective Comparison of Modern Video Codecs. |
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http://compression.ru/video/codec_comparison/subjective_codecs_comparison_en.html |
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<br />''Provides a subjective comparison of reference video from DVD and four video codecs (DivX, XviD, x264, and WMV) using four movie clips and quantified opinions of 50 experts. Their conclusion was that x264 provides superior quality to the other codecs.'' |
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| <ref>German C’T Magazine, May 03, compared various codecs, including VC-1 and H.264, and selected VC-1 as producing the best subjective and objective quality for high-definition (HD) video. [http://forum.doom9.org/showthread.php?s=&threadid=52410] [http://www.heise.de/ct/03/10/146/ intro] [http://www.heise.de/ct/03/10/146/testsequenzen.shtml] [http://www.heise.de/ct/03/10/146/tabelle_engel.shtml] [http://www.heise.de/ct/03/10/146/tabelle.shtml]</ref> <ref> http://www.microsoft.com/windows/windowsmedia/howto/articles/vc1techoverview.aspx#QualityComparison </ref> |
| <ref>German C’T Magazine, May 03, compared various codecs, including VC-1 and H.264, and selected VC-1 as producing the best subjective and objective quality for high-definition (HD) video. [http://forum.doom9.org/showthread.php?s=&threadid=52410] [http://www.heise.de/ct/03/10/146/ intro] [http://www.heise.de/ct/03/10/146/testsequenzen.shtml] [http://www.heise.de/ct/03/10/146/tabelle_engel.shtml] [http://www.heise.de/ct/03/10/146/tabelle.shtml]</ref> <ref> http://www.microsoft.com/windows/windowsmedia/howto/articles/vc1techoverview.aspx#QualityComparison </ref> |
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Revision as of 16:49, 7 July 2007
H.264 and VC-1 are popular video compression standards gaining use in the industry as of 2007. This article outlines commonalities and differences with the two standards.
Overview
| H.264 | VC-1 | |
|---|---|---|
| Goals | Designed to meet a variety of industry needs with many profiles and levels [1] | Designed to require lower processing power. [5] |
| Example industry use | Supports studio archiving requirements with 4:4:4 color space | Currently only supports 420 compression / color space[2] |
| Example industry use (2) | Compresses black and white (BW) video well | Does not have special support for BW |
| Video Quality | [3] | [4] [5] |
| Performance demands | Can decode 1080p video on more PCs [6] [7] [8] | |
| Licensing costs | Similar [9] | Similar [10] [11] |
| Documentation | 41 figures in the spec | 186 figures in the spec. Reference encoder and decoder come with external documentation. |
| Timeline: First version of specification published | May 2003[6] | March 2006 [12] |
- ^ http://www.itu.int/rec/dologin_pub.asp?lang=e&id=T-REC-H.264-200503-I!!PDF-E&type=items Section 0.3
- ^ SMPTE Draft Standard for Television, SMPTE421M, SMPTE Technology Committee C24 on Video Compression Technology, Proposed SMPTE Standard for Television: VC-1 Compressed Video Bitstream Format and Decoding Process, Date: 2005-08-23, Copyright 2003-2005 THE SOCIETY OF MOTION PICTURE AND TELEVISION ENGINEERS 595 W. Hartsdale Ave. White Plains, NY 10607 E-mail eng@smpte.org Web www.smpte.org
- ^
MSU Subjective Comparison of Modern Video Codecs.
http://compression.ru/video/codec_comparison/subjective_codecs_comparison_en.html
Provides a subjective comparison of reference video from DVD and four video codecs (DivX, XviD, x264, and WMV) using four movie clips and quantified opinions of 50 experts. Their conclusion was that x264 provides superior quality to the other codecs. - ^ German C’T Magazine, May 03, compared various codecs, including VC-1 and H.264, and selected VC-1 as producing the best subjective and objective quality for high-definition (HD) video. [1] intro [2] [3] [4]
- ^ http://www.microsoft.com/windows/windowsmedia/howto/articles/vc1techoverview.aspx#QualityComparison
- ^ From H.264 article intro
Terminology
All sources for the below information are from the respective specifications listed in the overview section.
| H.264 | VC-1 | |
|---|---|---|
| Block | MxN size | An 8x8 array of samples |
| Frame | Used for interlace content. Consists of bottom and top field | Used for progressive or interlaced content |
| Macroblock | 16x16 array of samples | Same |
| Motion vector | Two dimensional vector offset from current position to reference frame | Same |
| Picture | A field or frame | Same |
| Skipped macroblock | No data is encoded for macroblock | Same |
Features
| H.264 | VC-1 | |
|---|---|---|
| Bitstream formats | NAL and byte stream | defines only a single bit stream |
| Bitstream format | Sequence header (SPS, sequence parameter set), picture header (PPS, picture parameters set), slice, macroblock |
Same, called Seq_layer, and Pic_layer |
| CABAC | Yes | No |
| CAVLC | Yes | No |
| Variable Length Coding | Yes | Yes |
| Slice | Can be non contiguous in picture | Must be contiguous |
| Sub pixel interpolation methods | 6-tap filter for half pixel, averaging for quarter pixels | bicubic and bilinear |