Use VST 2.x plugins as audio filters in OBS.
tests/save_while_processing_test.cpp checks that saving the filter (vst_save()) and opening, hiding or closing its editor don't interrupt live audio, and that getChunk() rejects a chunk whose reported size is larger than the data received. It runs the real VSTPlugin code against a fake in-process proxy, so no VST plug-in or win-streamlabs-vst.exe is needed. It's Windows only.
The test is only built when BUILD_TESTING is on. From the obs-studio root:
cmake -S . -B build_x64 -DBUILD_TESTING=ON
cmake --build build_x64 --config RelWithDebInfo --target sl-vst-save-while-processing-test
ctest --test-dir build_x64 -C RelWithDebInfo -L sl-vst --output-on-failure
A passing run prints PASSED: audio kept processing during save and editor open/hide/close. You can also run build_x64/plugins/sl-vst/RelWithDebInfo/sl-vst-save-while-processing-test.exe directly, but ctest adds the libobs and FFmpeg DLL folders to PATH for you.
- http://teragonaudio.com/article/How-to-make-your-own-VST-host.html
- http://www.reaper.fm/sdk/vst/vst_ext.php
- https://forum.juce.com/t/mac-64-bit/6295/5
- https://gist.github.com/t-mat/206e3e7dfc3f89421bc1
- https://github.com/audacity/audacity/blob/17afc51644b2b327e173a23d6066dde598838c03/src/effects/VST/aeffectx.h
In general VST 2.4 is platform independent. There are only three platform dependent opcodes :
effEditOpen
audioMasterGetDirectory
audioMasterOpenFileSelectorHere are the required API changes for 64 bit Mac OS X:
effEditOpen:
the [ptr] argument is a WindowRef on 32 bit Mac.
On 64 bit this is a NSView pointer. The plug-in needs to add its own NSView as subview of it.audioMasterGetDirectory:
the [return value] is a FSSpec on 32 bit Mac.
On 64 bit this is a char pointer pointing to an UTF-8 encoded string.audioMasterOpenFileSelector:
the VstFileSelect struct uses FSSpec's on 32 bit Mac.
On 64 bit Mac these are char pointers pointing to UTF-8 encoded strings.