I’ve added link to the bug tracker on Google Code and I will be checking it a lot more often. It’s the best way of submitting documentation corrections as well. Just remember to quickly check the closed reports too because I usually only upload a new documentation revision when a new version is released of VapourSynth. You can find the link in the sidebar.

R15 had a serious issue that prevented the Avisynth compatibility stuff from working with anything except YV12, this release mainly fixes it. There isn’t much else new of interest in this release.

If you need more stuff to fidget with then go try the new resizers for VapourSynth too. They will most likely replace swscale once they become stable so testing is appreciated. They’re based on the dither tools code.

Next on my own todo list is a plugin to evaluate expressions at run-time, think mt_lutxy(z) but without insane memory requirements for 16bit formats. The other thing on the list mostly is about VSFS and that is to improve error handling and adapt the code to the latest Pismo File Mount API.

The time has come to break the API slightly to add some missing features. It also ends the alpha support discussion. The proper (and only) way to handle alpha is to return it as a separate mask clip. To make this easier filters now have a reasonably simple API to return more than one clip.

The new filters this time try to fill in some of the biggest feature holes, they are Merge, MaskedMerge and AVISource. MaskedMerge is very similar to masktool’s mt_merge in terms of functionality and the other two are very similar to the internal Avisynth filters with the same name. AVISource can of course open both VapourSynth and Avisynth scripts for import too.

There are also minor changes that need to be done to make plugins compile (binary compatibility with old plugins is however preserved). Previously the VSNodeRef type was always declared as const, this superfluous const declaration has now been removed everywhere in the API. Below are examples of the other two changes needed.

vsapi->setVideoInfo(a, b);
Change it to:
vsapi->setVideoInfo(a, 1, b);

The other construct that needs changing is filter creation which now automatically assigns itself to the out map:

cref = vsapi->createFilter(in, out, "Invert", invertInit, invertGetFrame, invertFree, fmParallel, 0, data, core);
vsapi->propSetNode(out, "clip", cref, 0);
vsapi->freeNode(cref);
Change it to:
vsapi->createFilter(in, out, "Invert", invertInit, invertGetFrame, invertFree, fmParallel, 0, data, core);

And don’t forget to check out my previous post with suggested tasks if you want to help out.

I’ve hinted that there are plenty of things left to do before. Especially in my forum posts. Repeatedly. So in this post I’ll list some tasks I think should be done. Not all of them are programming either.

• Proofread the documentation — most it was written after midnight so suggest clarifications too
• Write testcases to cover more parts of the code — testing the python bindings is important too so only some scripting knowledge needed to help out with it
• Add override file support to VIVTC (good entry level programming task)
• Convert the EEDI3 port to pure C (simple if you know the difference between C and C++)
• Port your favorite function/plugin from Avisynth — there’s something for everyone here
• Port your favorite Avisynth script
• Make a nice editor with preview — think AvsP
• Write some simple getting started examples or maybe a quick introduction for Avisynth users
• Add support for more output formats in vfw — clean up the output code too a bit
• Write a good implementation of edge detection filters — canny, sobel and friends for higher depths would be nice
• Your own ideas here

I never mentioned the minimum requirements for VapourSynth. I completely forgot about it. It wasn’t until a poor ancient Athlon user reported crashes I remembered that I actually do have minimum requirements. So what are they? and why?

• A CPU with SSE2 support (may be disregarded if not running on an x86 CPU)
• XP SP3 or later (may be disregarded if not a windows user of course)

That’s it! Not so bloody. The rationale for only supporting XP and later mostly comes down to testing. There’s simply no one who uses older systems around to provide testing. Maybe my code will run,  maybe it won’t, but there’s no way to justify spending time testing it myself.

SSE2 on the other hand requires a bit more motivation. It’s very good to have when optimizing filters. Also, most CPUs support it today, it has reached the levels MMX support had 10 years ago or so. Every single x64 CPU must also support it. It’s everywhere.  And it’s good. For example the transpose function in VapourSynth runs a bit over 10 times faster with SSE2 optimizations.

I think that’s all I have to say about the minimum requirements. There’s always Avisynth for the few who don’t qualify.

Jeeb’s patch to add the high bitdepth y4m formats has now made its way into x264. This means that you can now use y4m for 10 bit input too and save the trouble of manually specifying the input properties.