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    Scriptnode pitch-shift a signal

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    • griffinboyG
      griffinboy @aaronventure
      last edited by

      @aaronventure
      Thank you!
      I haven't looked into FAUST yet, this is a good time to start

      Christoph HartC 1 Reply Last reply Reply Quote 0
      • Christoph HartC
        Christoph Hart @griffinboy
        last edited by

        Link Preview Image
        hise_tutorial/PitchShifting at master · christophhart/hise_tutorial

        The Tutorial project for HISE. Contribute to christophhart/hise_tutorial development by creating an account on GitHub.

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        GitHub (github.com)

        This uses two delay lines and fades between them. Note that the sound quality is far worse than what you expect from an industry standard pitch shifter (and the pitch shifter in Faust uses the same algorithm with only little sound quality improvement).

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          aaronventure @Christoph Hart
          last edited by

          @Christoph-Hart so what would an industry standard pitch shifter do different, then? What's the catch?

          Christoph HartC 1 Reply Last reply Reply Quote 0
          • Christoph HartC
            Christoph Hart @aaronventure
            last edited by

            @aaronventure I'm not 100% sure, but I guess it involves using a good timestretching library optimized for low latency that can handle live audio input.

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            • hisefiloH
              hisefilo @griffinboy
              last edited by

              @griffinboy hi mate! Faust is the way for me. Just google shimmer + faust + dsp
              i.e https://github.com/azur1s/elysiera/blob/main/faust/dsp.dsp

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                ps @Christoph Hart
                last edited by

                @Christoph-Hart 1024 samples (50ms) is what all the "realtime" pitch shifter plugins introduce.

                the signal smith demo https://signalsmith-audio.co.uk/code/stretch/demo/ set to 50ms block size sounds on monophonic signals pretty much how you would expect "industry standard" rt pitch shifter to sound like .
                would it be a crazy amount of work to basically replicate the web demo but with an audio stream?

                the following looks even better for "realtime" processing and has a MIT license:

                Link Preview Image
                GitHub - jurihock/stftPitchShift: STFT based real-time pitch and timbre shifting in C++ and Python

                STFT based real-time pitch and timbre shifting in C++ and Python - jurihock/stftPitchShift

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                GitHub (github.com)

                used in here:
                https://github.com/jurihock/stftPitchShiftPlugin

                I tried to implement it already but failed (I think because it's not c++11)

                do you want to take a look? I think it opens up really cool currently not possible opportunities straight out of the box.

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                  ps @ps
                  last edited by

                  @Lindon @Christoph-Hart after posting this I started to write my own c++ code inspired by all the different algorithms available and can say that for "realtime" pitch shifting there is not really a one fits all solution but it's very doable and I got it up and running (but still optimising) . my use case right now is vocal manipulation and besides the fact that you have to really play around with window sizes, overlapping and so on - there is some other stuff that is needed for a industry standard result. I saw that autotune or little alterboy are reporting very odd latency to the host. so I figured there has to be additional sfft processing happening and it is resonance suppression. so before doing the actual shift I lower the magnitude of bins (above a certain frequency) to avoid resonances hitting the shifting algorithm. formant shifting sounds shit yet but I'm working on this right now.
                  Summary is that I don't see myself coming up with a node that I just use in different projects.
                  and if you go down the road, don't accidentally process per Frame or your computer will explode ;)

                  Christoph HartC 1 Reply Last reply Reply Quote 2
                  • Christoph HartC
                    Christoph Hart @ps
                    last edited by

                    D'oooh, I didn't even think about trying out the signal smith algorithm...

                    The implementation was dead easy and the sound is way way WAY better than the naive pitch shifting from Faust or scriptnode (kind of obvious, that was the entire point of the JUCE talk of the signalsmith developer). However there is a latency of 4096 samples which is kind of huge - you can set the FFT to 2048, but then it will sound very bad on lower notes.

                    A LindonL 2 Replies Last reply Reply Quote 4
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                      aaronventure @Christoph Hart
                      last edited by

                      @Christoph-Hart will this be replacing or augmenting the timestretch for the sampler as well?

                      Christoph HartC 1 Reply Last reply Reply Quote 0
                      • Christoph HartC
                        Christoph Hart @aaronventure
                        last edited by Christoph Hart

                        @aaronventure No I just took the timestretching algorithm that's already in the sampler and made it a realtime effect that works on any audio signal.

                        d.healeyD 1 Reply Last reply Reply Quote 1
                        • d.healeyD
                          d.healey @Christoph Hart
                          last edited by

                          @Christoph-Hart Does this mean we can have a pitch LFO in effects plugins now?

                          Libre Wave - Freedom respecting instruments and effects
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                          Christoph HartC 1 Reply Last reply Reply Quote 0
                          • LindonL
                            Lindon @Christoph Hart
                            last edited by

                            @Christoph-Hart well the stftPitchShift looks pretty good - and quick and has a MIT license...

                            HISE Development for hire.
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                              ps @Lindon
                              last edited by

                              @Lindon @Christoph-Hart
                              stftPitchShift is def the best out there I could find - it can do polyphonic and also formant shift.
                              2048samples latency is normal for pitch shifting audio (it's also normal that low signals sound bad when pitch shifted in those kind of plugins)
                              I'd love to see that implemented as well :)

                              Christoph HartC 1 Reply Last reply Reply Quote 0
                              • Christoph HartC
                                Christoph Hart @ps
                                last edited by

                                @ps I played around with it yesterday but it always sounded very cheap. I‘m definitely doing something wrong maybe I‘ll try their JUCE example and go from there.

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                                • Christoph HartC
                                  Christoph Hart @d.healey
                                  last edited by

                                  @d-healey said in Scriptnode pitch-shift a signal:

                                  @Christoph-Hart Does this mean we can have a pitch LFO in effects plugins now?

                                  A pitch lfo can be made with a simple delay buffer that modulates the delay time (a basic chorus), a pitchshifter would be overkill.

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                                    ps @Christoph Hart
                                    last edited by

                                    @Christoph-Hart did you align the pitch shift with the timbre shift and set a timbre frequency to around 2.5 - 3ms?

                                    if the formants are not shifted together with the signal it will sound strange :)

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                                      ps @Christoph Hart
                                      last edited by

                                      @Christoph-Hart can you point me in the direction how you included the library? i fail drastically somehow.

                                      Christoph HartC 1 Reply Last reply Reply Quote 0
                                      • Christoph HartC
                                        Christoph Hart @ps
                                        last edited by

                                        @ps I added a third party node, included all files in there and then fought an epic battle until all compile errors went away.

                                        You need to use a replacement for std::span (I ended up with tcb::span) as this is a C++20 feature.

                                        However I'm really not convinced about the quality here - the CPU usage is 2-3 times as high as signalsmith and the sound is super bad. The latency is a bit better, but that's really the only thing that this library has going for them.

                                        Also the coding style is super counterintuitive - I literally had to copy the entire plugin code into the node and write a wrapper because I couldn't figure out how it expects the different buffer sizes to work.

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                                          ps @Christoph Hart
                                          last edited by ps

                                          @Christoph-Hart can you share the node template with me? I'm doing something wrong - I get 2000% cpu even though I'm pretty confident I do the processing in buffers haha

                                          btw in general It would be interesting to see how you write a wrapper around a juce plugin code and integrate it as node :)

                                          Christoph HartC 1 Reply Last reply Reply Quote -1
                                          • Christoph HartC
                                            Christoph Hart @ps
                                            last edited by

                                            @ps Are you using the debug build? If you don't build the release configuration it also maxes out my CPU here with a single instance.

                                            btw in general It would be interesting to see how you write a wrapper around a juce plugin code and integrate it as node :)

                                            Sure, here you go:

                                            ThirdParty.zip

                                            This is definitely not anything I'm proud of - I just want to get this thing to work so the coding style is all over the place. If this would make it into HISE it would require a almost 100% rewrite including swapping out whatever weird thing they are using for the FFT with the proper libraries (IPP / vDSP) etc, but I'm rather sceptical at the moment that it's worth the hassle.

                                            You might have to set the USE_JUCE_PROCESSOR preprocessor to true and manually add a few JUCE modules to the DLL Projucer project (I think audio_processor & hi_streaming are missing).

                                            P 2 Replies Last reply Reply Quote 0
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