fast encoding video codec?

can anybody compare popular video codecs by encoding speed? I understand that usually better compression requires more processing time, but it's also possible that some codecs still provide comparably good compression with fast encoding. any comparison links?

thanks for your help

[EDIT]: codecs can be compared by used algorithms, regardless of its particular implementation, hardware used or video source, something like big O for mathematical algorithms

When comparing VP8 and x264, VP8 also shows 5-25 times lower encoding speed with 20-30% lower quality at average. For example x264 High-Speed preset is faster and has higher quality than any of VP8 presets at average."

its tough to compare feature sets vs speed/quality.

see some quality comparison http://www.compression.ru/video/codec_comparison/h264_2012/

The following paragraph and image are from VP9 encoding/decoding performance vs. HEVC/H.264 by Ronald S. Bultje:

x264 is an incredibly well-optimized encoder, and many people still use it. It’s not that they don’t want better bitrate/quality ratios, but rather, they complain that when they try to switch, it turns out these new codecs have much slower encoders, and when you increase their speed settings (which lowers their quality), the gains go away. Let’s measure that! So, I picked a target bitrate of 4000kbps for each encoder, using otherwise the same settings as earlier, but instead of using the slow presets, I used variable-speed presets (x265/x264: –preset=placebo-ultrafast; libvpx: –cpu-used=0-7).