R49 – Just another release

There’s a new release that fixes all known R48 regressions and bugs. Not much else to say about it really. One notable thing is that I got myself a raspberry pi recently so now I can actually test compilation on ARM easily and it won’t be broken all the time. I guess that’s interesting for some people.

Audio Support and how it works

Finally the first test version of audio support is ready and this post will describe how it works. Spoiler: It doesn’t work like in Avisynth.

In Python scripts audio nodes are just another unique type. They aren’t stuck together with a video track like in Avisynth. This can be both an advantage and a disadvantage, for example cutting audio and video at the same time by frame numbers will currently require a bit of user scripting. On the other hand with the correct helper functions it’ll be possible to manipulate multiple audio and video tracks as a group easily. Audio also always has a constant format unlike video.

Feedback and downloads are on the Doom9 forum as usual for highly experimental things.

Audio filters

  • BestAudioSource – a new sample accurate but somewhat slow FFmpeg based source filter (usage: core.bas.Source(“rule6.mp4”))
  • BlankAudio – a classic
  • AudioSplice and AudioTrim – with the expected Python overloads of course

Output support

  • VSPipe – outputs raw pcm audio and using the -y switch adds wave64 headers
  • AVFS – uses the audio node assigned to output slot 1
  • VFW – uses the audio node assigned to output slot 1 and video must be assigned to slot 0

An output example

import vapoursynth as vs
audio = vs.core.bas.Source("somefile.mp3", track=-1)
video = vs.core.std.BlankClip()
video.set_output(0)
audio.set_output(1)

API Notes and Changes

Currently the API isn’t completely stable but only minor changes are expected at this point so starting to port plugins. The only mildly breaking change is that the clip type in function argument strings now has been renamed to vnode and obviously the new anode type has been introduced which may confuse existing software tries to parse the argument strings.

The best way to think of audio nodes is as a type completely separate from video nodes that only happen to share some functions to manipulate them. For example you can’t mix audio and video nodes in the same VSMap key or in any other context.

R48 – AVX2 Instrinsics for Everyone!

After several weeks of testing R48 is finally done. As you may suspect from the title the biggest change this time is optimizations. Now most internal functions have proper AVX2 optimizations and in addition to that the Expr filter was greatly improved and can now rewrite and optimize expressions much better. In addition to that a lot of bugs were fixed and the installer got a few more options. Users of R47 should definitely upgrade.

R47 – Fixing small issues

Since R46 was a release with some big changes in regards to the installer this one simply cleans up all the minor issues that were found. And one annoying zimg bug that could cause a crash on some invalid conversions.

Breaking changes:

  • All assembler was removed in favor of intrinsics, this means that x86inc.asm will no longer be installed as a public header
  • NASM obviously isn’t required anymore

R46 – Windows installer fun

The yearly slowdown is over so now it’s time for a maintenance release which will probably still manage to introduce a lot of new issues due to the windows installer changes. Here’s a list of the main changes:

  • Separate installers for 32 and 64 bit
  • It’s now possible to install without administrator privileges
  • The Python module is now a proper package

As usual there are also a few possibly breaking changes:

  • The 32 bit VapourSynth registry entries are now stored in a key called VapourSynth-32 in order to better distinguish it from the 64 bit version
  • The installer no longer installs the VS2013 runtimes by default due to VapourSynth not actually needing them for many years