int64.org

ResampleHQ

Our eyes don't per­ceive light lin­early. Twice the pho­tons will not ap­pear twice as bright. To ac­count for this, col­or­spaces with small bit widths (all the ones in Avisynth) are gamma-com­pressed to give a more eye-friendly rep­re­sen­ta­tion, en­sur­ing bits are evenly dis­trib­uted across all per­ceived in­ten­si­ties.

These gamma-com­pressed col­ors must be con­verted back to a lin­ear col­or­space prior to blend­ing, or you get in­cor­rect re­sults. None of Avisynth's fil­ters do this cor­rectly. For rare scenes with a lot of sharp con­trast this causes very pro­nounced er­rors. For most other scenes the er­rors are more sub­tle. It can also ef­fect the qual­ity of anti-alias­ing on edges with a lot of con­trast (such as in out­line-heavy anime and car­toons).

Re­sam­pleHQ pro­duces cor­rect re­sults using a high-pre­ci­sion 100% lin­ear pipeline. Be­cause col­or­space con­ver­sion and re­siz­ing are often es­sen­tially the same thing, we can per­form both op­er­a­tions at once for higher per­for­mance and bet­ter qual­ity.

Contributing

Re­sam­pleHQ will al­ways be free, but do­na­tions are still ap­pre­ci­ated and will help me fig­ure out what to spend my time on. Any small amount helps!

If you're a pro­gram­mer and would like to con­tribute a patch, please email me.

Open Source

Re­sam­pleHQ is Open Source and dis­trib­uted under a GNU Gen­eral Pub­lic Li­cense v3.0. The source code can be viewed on­line or down­loaded through Sub­ver­sion:

svn co https://svn.int64.org/svnroot/int64/resamplehq resamplehq

Re­sam­pleHQ also uses Boost, an­other great piece of Open Source soft­ware.