JUCE FFT and Intel IPP


I believe the JUCE FFT on Mac uses the Accelerate framework so in an effort to improve FFT performance on Windows (specifically the FIR class) I have installed Intel IPP and ticked the “Use Intel IPP” box in the Projucer.

Is that it?

Do I need to do anything else?

How do I verify the FFT class is using IPP?

Yes, that’s all you need to do.

To check that IPP is being used you can stick a breakpoint at juce_FFT.cpp:829, just inside IntelPerformancePrimitivesFFT::create (const int), and then launch the program. The breakpoint will be hit if IPP is being used.

On SR’s branch JUCE uses the IPP FFT on Intel Macs if you want (set JUCE_IPP_AVAILABLE=1), we’ve found that it is slightly faster than Apple’s.

Here’s something I’ve noticed. I have to enable the IPP libraries manually in Visual Studio 2019 otherwise the Properties section for the shared code target is set to “NO” until I set it to Static Library as below.

Is your Projucer built from the very latest develop? I added a feature very recently to support the new “oneAPI” distribution of the IPP library:

If you haven’t tried this yet, please rebuild Projucer from the current develop branch, ensure that “Use IPP Library (oneAPI)” is set to an appropriate value, then resave your project and try building it in Visual Studio.


No, I’m using the latest download 6.0.8. Ok, I’ll give that a go, thanks!

Yes, that works and breakpoints hit at IntelPerformancePrimitivesFFT::create().

Here’s an odd thing. Every time I open a session with the Projucer built from the develop branch some of the settings revert to defaults. For example Runtime Library reverts to DLL when it should be static for this plugin:

I’ve noticed this too, but was unsure if this was a byproduct of rebuilding the Projucer more often, and the settings reverting to defaults each time the Projucer was rebuilt. I’ve been adding new fields in prep to submit some PRs for mobile exporter feature requests and was trying to pinpoint exactly when the values were being reset to defaults.

I’ve put a potential fix together. It still needs to be reviewed by the team, but it’ll hopefully be out in the next few days.


@reuk does FloatVectorOperations support using IPP internally yet?

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Not currently, no.

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Thanks for reporting this issue. It should be fixed by this commit:



I’m struggling to get Intel IPP working with JUCE via Projucer & VS2022/Clang on Windows 11, which I’m pursuing in order to potentially accelerate dsp::convolution inside my VST3 plugins.

Could somebody please help me out with a clue as to what I’ve missed?

I haven’t yet found a consolidated step-by-step guide to activating IPP, but in a game of trial and error I’ve tried several combinations of the below steps that I found around the web (including from this thread):

  1. Installing the Intel [oneAPI Base Toolkit]. (Download the Intel® oneAPI Base Toolkit)
  2. Adding #include “ipp.h” in PluginProcessor.h
  3. Setting Projucer/Exporters/VS2022/Use IPP Library (oneAPI) = Static Library
  4. Setting Projucer/Exporters/VS2022/(deprecated) Use IPP Library = Single-Threaded Static Library
  5. Setting Projucer/Exporters/VS2022/Release/Header Search Paths = C:\Program Files (x86)\Intel\oneAPI\ipp\latest\include\ipp
  6. Setting Projucer/Exporters/VS2022/Release/Extra Library Search Paths = C:\Program Files (x86)\Intel\oneAPI\ipp\latest\lib
  7. Setting Projucer/Exporters/VS2022/Extra Preprocessor Definitions = DEFINE _IPP_SEQUENTIAL_STATIC 1 (h/t @PeterRoos)
  8. Alternatively adding atop my PluginProcessor.h #define _IPP_SEQUENTIAL_STATIC 1
  9. Checking for success by trying to hit a debugger breakpoint inside juce_FFT.cpp just before line 824 (in JUCE v7.0.9): static IntelPerformancePrimitivesFFT* create (const int order)

Note, my dsp::convolution code works OK with the normal JUCE FFT, i.e. without IPP.

Using step 8, I can build but I don’t encounter the breakpoint upon execution (per step 9).

Using step 7, building produces 28 errors “macro name must be an identifier”, almost all in line 9 of “MyPlugin_SharedCode”. I can’t find a source file of this name, but my build folder does contain a MyPlugin_SharedCode.log file, which is basically a copy of my VS2022 Output window, except each instance of the error is appended with “In file included from (built-in):422:”

I found this post discussing the “macro name must be an identifier” error, and tried setting Projucer/Settings/Use Global AppConfig Header = Enabled (h/t @reuk), which unfortunately didn’t help.

Any guidance much appreciated!

OK I figured this out, with help from some folks over on discord.

In case anyone else is facing the same challenge, here is an improved version of the above, with just the steps that seem important for getting JUCE to switch to the Intel IPP FFT algorithm on PC (specifically w.r.t. juce::convolution):

  1. Install Intel oneAPI: Download the Intel® oneAPI Base Toolkit
  2. Set Projucer/Exporters/VS2022/Use IPP Library (oneAPI) = Static Library
  3. Set Projucer/Exporters/VS2022/Release/Header Search Paths = C:\Program Files (x86)\Intel\oneAPI\ipp\latest\include\ipp
  4. Set Projucer/Exporters/VS2022/Release/Extra Library Search Paths = C:\Program Files (x86)\Intel\oneAPI\ipp\latest\lib
  5. Set Projucer/Exporters/VS2022/Extra Preprocessor Definitions = _IPP_SEQUENTIAL_STATIC=1
  6. Check for success by trying to hit a debugger breakpoint inside juce_FFT.cpp at line 829 (assuming JUCE v7.0.9), inside the function “static IntelPerformancePrimitivesFFT* create (const int order)”; more importantly look for a significant improvement in FFT speed. I still need to run further performance tests, but I’m pretty sure I’m seeing a >2x speedup.