CodecComparison
From Diracvideo
[edit] Comparison table
(please add what's missing and fix what's wrong :-) , most notably additional justification of inventing a new codec and pushing into a such oversaturated market)
Comparing Dirac against some other notable lossy video codecs:
| Codec name: | Dirac | Snow | Theora | MPEG-4 | WMV-3 | |
| ... | ... | ... | ... | ... | ... | |
| Created by: | BBC, Tim Borer, Thomas Davies, David Schleef & other contributors | Michael Niedermayer, FFMPEG contributors | On2 Technologies, Xiph foundation | MPEG team | Microsoft | |
| Design goal, primary license: | Free & OS | Free & OS | Free & OS | Proprietary and patented, but publicly documented ("open") | Proprietary and secret (but got "reversed") | |
| Target public: | ?? | ?? | Open media geeks | Professionals and like-to-be professionals | "windows" users, everybody, noobs ? | |
| Time of becoming useful or popular: | not yet, pending for 2008 ? | not yet | slowly 2004...2008 | 1998...2004 (had already versions MPEG-1 and MPEG-2 before) | 2002...2004 (had already versions WMV-1 and WMV-2 before) | |
| Reference implementation: | There are 2: "Dirac" and "Schrodinger" | ?? | LibTheora | Proprietary MPEG lib ? | WME/WMM, WMP, codec DLL (?) | |
| Reference implementation details: | "Dirac": C++, LGPL, Alpha, "Schrodinger": plain C, BSD-like license, 1.0 is out, bitstream not yet frozen (?), mostly done (?) | Alpha (?) | Libtheora: plain C, BSD-like license, Beta approaching 1.0 release, bitstream "frozen" already years ago | Development status: Done | Development status: WMV-3 done, WMV-4 might come soon :-( | |
| (proprietary codecs only) Alternative OS implementation (legal status still grey): | -- | -- | -- | YES, several, both encoding and decoding, LGPL | YES, LGPL, decoding only | |
| (free codecs only) Documentation: | PDF, version 2.2.0 from 2008-Apr, cca 1 MiB, still evolving | Draft, cca 20 KiB plain text | PDF, cca 1 MiB from 2008,still evolving | -- | -- | |
| ... | ... | ... | ... | ... | ... | |
| Codec name: | Dirac | Snow | Theora | MPEG-4 | WMV-3 | |
| ... | ... | ... | ... | ... | ... | |
| Major transformations of video data / tricks to reduce size: | RBG->YUV (or similar), optional chroma subsampling, wavelet compression, optional frame-diff | Wavelet compression (?) | RGB->YUV, chroma subsampling, blocking&mixing, DCT, Huffman, frame-diff | RGB->YUV, chroma subsampling, blocking&mixing, DCT, Huffman, frame-diff | RGB->YUV, chroma subsampling, blocking&mixing, DCT, Huffman, frame-diff | |
| Preferred container: | ?? (OGG ASAP ? plus some other possibilities) | ?? | OGG | MP4 or similar MPEG container, AVI | WMV/ASF, AVI | |
| Preferred audio codec: | Vorbis, FLAC | ?? | Vorbis, FLAC | MP3,AAC | WMA, MP3 | |
| Image data quality, size reduction factor: | above average ?? | above average ?? | average | average ?? | average ?? | |
| Codec "cost" (algo complexity, CPU performance): | above average ?? | above average ?? | average | average ?? | average ?? | |
| Video size: | wide-range | ?? | wide-range:1 to 1048560 pixels per dimension | ?? | ?? | |
| Color models, subsampling, bitdeph: | YCbCr(YUV), YCoCg and more (one luma plus 2 chroma planes), sub 4:4:4, 4:2:2, 4:2:0, wide-range bitdepth | ?? | YCbCr(YUV), mostly 4:2:0, also 4:4:4 and 4:2:2 possible, bitdepth 3x8bpp only | YUV, 4:2:0 (?) | ?? | |
| Lostless compression also possible ? | YES (?) | NO (?) | NO | NO | NO | |
| DRM supported/possible ? | NO (?) | ?? | NO | YES | YES | |
| Streamable ? | YES (?) | ?? | YES | YES (some container subversions) | YES (?) | |
| Available encoders: | None ? MENCODER ASAP ? | MENCODER ? | FFMPEG2THEORA, PNG2THEORA example, VLC, NOT supported by MENCODER | Hardware encoders, proprietary video software, MENCODER | WME/WMM | |
| Available decoders and players: | None ? MPLAYER ASAP ? | MPLAYER ? | MPLAYER, VLC, Opera browser (?) | Hardware players, MPLAYER, VLC, QuickView | WMP, MPLAYER, VLC | |
| (free codecs only) Availability and quality of examples of codec/lib usage: | ?? | NO ? | Partial, leaves space for improvements | -- | -- | |
| Movies availability: | None yet ?? | NO ?? | YES, limited (mostly Wikimedia) | YES | YES (very dominant) :-( | |
| Free movie hosting availability: | NO | NO | YES, limited (mostly Wikimedia) | YES | YES | |
| ... | ... | ... | ... | ... | ... | |
| Codec name: | Dirac | Snow | Theora | MPEG-4 | WMV-3 |
