JackFilters.h

/*
Copyright (C) 2008 Grame

This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.

*/

#ifndef __JackFilters__
#define __JackFilters__

#ifdef __APPLE__
#include <TargetConditionals.h>
#endif

#include "jack.h"
#ifndef MY_TARGET_OS_IPHONE
#include "JackAtomicState.h"
#endif
#include <math.h>
#include <stdlib.h>

namespace Jack
{

#ifndef TARGET_OS_IPHONE

    #define MAX_SIZE 64

    PRE_PACKED_STRUCTURE
    struct JackFilter
    {

        jack_time_t fTable[MAX_SIZE];

        JackFilter()
        {
            for (int i = 0; i < MAX_SIZE; i++) {
                fTable[i] = 0;
            }
        }

        void AddValue(jack_time_t val)
        {
            memcpy(&fTable[1], &fTable[0], sizeof(jack_time_t) * (MAX_SIZE - 1));
            fTable[0] = val;
        }

        jack_time_t GetVal()
        {
            jack_time_t mean = 0;
            for (int i = 0; i < MAX_SIZE; i++) {
                mean += fTable[i];
            }
            return mean / MAX_SIZE;
        }

    } POST_PACKED_STRUCTURE;

    PRE_PACKED_STRUCTURE
    class JackDelayLockedLoop
    {

        private:

            jack_nframes_t fFrames;
            jack_time_t fCurrentWakeup;
            jack_time_t fCurrentCallback;
            jack_time_t fNextWakeUp;
            float fSecondOrderIntegrator;
            jack_nframes_t fBufferSize;
            jack_nframes_t fSampleRate;
            jack_time_t fPeriodUsecs;
            float fFilterCoefficient;   /* set once, never altered */
            bool fUpdating;

        public:

            JackDelayLockedLoop()
            {}

            JackDelayLockedLoop(jack_nframes_t buffer_size, jack_nframes_t sample_rate)
            {
                Init(buffer_size, sample_rate);
            }

            void Init(jack_nframes_t buffer_size, jack_nframes_t sample_rate)
            {
                fFrames = 0;
                fCurrentWakeup = 0;
                fCurrentCallback = 0;
                fNextWakeUp = 0;
                fFilterCoefficient = 0.01f;
                fSecondOrderIntegrator = 0.0f;
                fBufferSize = buffer_size;
                fSampleRate = sample_rate;
                fPeriodUsecs = jack_time_t(1000000.f / fSampleRate * fBufferSize);      // in microsec
            }

            void Init(jack_time_t callback_usecs)
            {
                fFrames = 0;
                fCurrentWakeup = 0;
                fSecondOrderIntegrator = 0.0f;
                fCurrentCallback = callback_usecs;
                fNextWakeUp = callback_usecs + fPeriodUsecs;
            }

            void IncFrame(jack_time_t callback_usecs)
            {
                float delta = (int64_t)callback_usecs - (int64_t)fNextWakeUp;
                fCurrentWakeup = fNextWakeUp;
                fCurrentCallback = callback_usecs;
                fFrames += fBufferSize;
                fSecondOrderIntegrator += 0.5f * fFilterCoefficient * delta;
                fNextWakeUp = fCurrentWakeup + fPeriodUsecs + (int64_t) floorf((fFilterCoefficient * (delta + fSecondOrderIntegrator)));
            }

            jack_nframes_t Time2Frames(jack_time_t time)
            {
                long delta = (long) rint(((double) ((long long)(time - fCurrentWakeup)) / ((long long)(fNextWakeUp - fCurrentWakeup))) * fBufferSize);
                return (delta < 0) ? ((fFrames > 0) ? fFrames : 1) : (fFrames + delta);
            }

            jack_time_t Frames2Time(jack_nframes_t frames)
            {
                long delta = (long) rint(((double) ((long long)(frames - fFrames)) * ((long long)(fNextWakeUp - fCurrentWakeup))) / fBufferSize);
                return (delta < 0) ? ((fCurrentWakeup > 0) ? fCurrentWakeup : 1) : (fCurrentWakeup + delta);
            }

            jack_nframes_t CurFrame()
            {
                return fFrames;
            }

            jack_time_t CurTime()
            {
                return fCurrentWakeup;
            }

    } POST_PACKED_STRUCTURE;

    PRE_PACKED_STRUCTURE
    class JackAtomicDelayLockedLoop : public JackAtomicState<JackDelayLockedLoop>
    {
         public:

            JackAtomicDelayLockedLoop(jack_nframes_t buffer_size, jack_nframes_t sample_rate)
            {
                fState[0].Init(buffer_size, sample_rate);
                fState[1].Init(buffer_size, sample_rate);
            }

            void Init(jack_time_t callback_usecs)
            {
                JackDelayLockedLoop* dll = WriteNextStateStart();
                dll->Init(callback_usecs);
                WriteNextStateStop();
                TrySwitchState(); // always succeed since there is only one writer
            }

            void Init(jack_nframes_t buffer_size, jack_nframes_t sample_rate)
            {
                JackDelayLockedLoop* dll = WriteNextStateStart();
                dll->Init(buffer_size, sample_rate);
                WriteNextStateStop();
                TrySwitchState(); // always succeed since there is only one writer
            }

            void IncFrame(jack_time_t callback_usecs)
            {
                JackDelayLockedLoop* dll = WriteNextStateStart();
                dll->IncFrame(callback_usecs);
                WriteNextStateStop();
                TrySwitchState(); // always succeed since there is only one writer
            }

            jack_nframes_t Time2Frames(jack_time_t time)
            {
                UInt16 next_index = GetCurrentIndex();
                UInt16 cur_index;
                jack_nframes_t res;

                do {
                    cur_index = next_index;
                    res = ReadCurrentState()->Time2Frames(time);
                    next_index = GetCurrentIndex();
                } while (cur_index != next_index); // Until a coherent state has been read

                return res;
            }

            jack_time_t Frames2Time(jack_nframes_t frames)
            {
                UInt16 next_index = GetCurrentIndex();
                UInt16 cur_index;
                jack_time_t res;

                do {
                    cur_index = next_index;
                    res = ReadCurrentState()->Frames2Time(frames);
                    next_index = GetCurrentIndex();
                } while (cur_index != next_index); // Until a coherent state has been read

                return res;
            }
    } POST_PACKED_STRUCTURE;

#endif

    /*
    Torben Hohn PI controler from JACK1
    */

    struct JackPIControler {

        double resample_mean;
        double static_resample_factor;

        double* offset_array;
        double* window_array;
        int offset_differential_index;

        double offset_integral;

        double catch_factor;
        double catch_factor2;
        double pclamp;
        double controlquant;
        int smooth_size;

        double hann(double x)
        {
            return 0.5 * (1.0 - cos(2 * M_PI * x));
        }

        JackPIControler(double resample_factor, int fir_size)
        {
            resample_mean = resample_factor;
            static_resample_factor = resample_factor;
            offset_array = new double[fir_size];
            window_array = new double[fir_size];
            offset_differential_index = 0;
            offset_integral = 0.0;
            smooth_size = fir_size;

            for (int i = 0; i < fir_size; i++) {
                offset_array[i] = 0.0;
                window_array[i] = hann(double(i) / (double(fir_size) - 1.0));
            }

            // These values could be configurable
            catch_factor = 100000;
            catch_factor2 = 10000;
            pclamp = 15.0;
            controlquant = 10000.0;
        }

        ~JackPIControler()
        {
            delete[] offset_array;
            delete[] window_array;
        }

        void Init(double resample_factor)
        {
            resample_mean = resample_factor;
            static_resample_factor = resample_factor;
        }

        /*
        double GetRatio(int fill_level)
        {
            double offset = fill_level;

            // Save offset.
            offset_array[(offset_differential_index++) % smooth_size] = offset;

            // Build the mean of the windowed offset array basically fir lowpassing.
            double smooth_offset = 0.0;
            for (int i = 0; i < smooth_size; i++) {
                smooth_offset += offset_array[(i + offset_differential_index - 1) % smooth_size] * window_array[i];
            }
            smooth_offset /= double(smooth_size);

            // This is the integral of the smoothed_offset
            offset_integral += smooth_offset;

            // Clamp offset : the smooth offset still contains unwanted noise which would go straigth onto the resample coeff.
            // It only used in the P component and the I component is used for the fine tuning anyways.
            if (fabs(smooth_offset) < pclamp)
                smooth_offset = 0.0;

            // Ok, now this is the PI controller.
            // u(t) = K * (e(t) + 1/T \int e(t') dt')
            // Kp = 1/catch_factor and T = catch_factor2  Ki = Kp/T
            double current_resample_factor
                = static_resample_factor - smooth_offset / catch_factor - offset_integral / catch_factor / catch_factor2;

            // Now quantize this value around resample_mean, so that the noise which is in the integral component doesnt hurt.
            current_resample_factor = floor((current_resample_factor - resample_mean) * controlquant + 0.5) / controlquant + resample_mean;

            // Calculate resample_mean so we can init ourselves to saner values.
            resample_mean = 0.9999 * resample_mean + 0.0001 * current_resample_factor;
            return current_resample_factor;
        }
        */

        double GetRatio(int error)
        {
            double smooth_offset = error;

            // This is the integral of the smoothed_offset
            offset_integral += smooth_offset;

            // Ok, now this is the PI controller.
            // u(t) = K * (e(t) + 1/T \int e(t') dt')
            // Kp = 1/catch_factor and T = catch_factor2 Ki = Kp/T
            return static_resample_factor - smooth_offset/catch_factor - offset_integral/catch_factor/catch_factor2;
        }

        void OurOfBounds()
        {
            int i;
            // Set the resample_rate... we need to adjust the offset integral, to do this.
            // first look at the PI controller, this code is just a special case, which should never execute once
            // everything is swung in.
            offset_integral = - (resample_mean - static_resample_factor) * catch_factor * catch_factor2;
            // Also clear the array. we are beginning a new control cycle.
            for (i = 0; i < smooth_size; i++) {
                offset_array[i] = 0.0;
            }
        }

    };

}

#endif

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