Support loading SOFA files directly with makemhr

This extracts the definition info it can from the SOFA, and uses the same logic
as sofa-info to automatically detect an appropriate layout. There is a bit of
code duplication from loaddef.cpp and sofa-info.cpp, though there are slight
modifications.

4 files changed, 662 insertions, 4 deletions

diff --git a/utils/makemhr/loadsofa.cpp b/utils/makemhr/loadsofa.cpp
index a60526a8..9ab88045 100644
--- a/utils/makemhr/loadsofa.cpp
+++ b/utils/makemhr/loadsofa.cpp
@@ -1,4 +1,653 @@
+/*
+ * HRTF utility for producing and demonstrating the process of creating an
+ * OpenAL Soft compatible HRIR data set.
+ *
+ * Copyright (C) 2018-2019  Christopher Fitzgerald
+ *
+ * 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.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Or visit:  http://www.gnu.org/licenses/old-licenses/gpl-2.0.html
+ */
+
+#include <memory>
+#include <algorithm>
 
 #include "mysofa.h"
 
 #include "loadsofa.h"
+
+
+static const char *SofaErrorStr(int err)
+{
+    switch(err)
+    {
+    case MYSOFA_OK: return "OK";
+    case MYSOFA_INVALID_FORMAT: return "Invalid format";
+    case MYSOFA_UNSUPPORTED_FORMAT: return "Unsupported format";
+    case MYSOFA_INTERNAL_ERROR: return "Internal error";
+    case MYSOFA_NO_MEMORY: return "Out of memory";
+    case MYSOFA_READ_ERROR: return "Read error";
+    }
+    return "Unknown";
+}
+
+
+/* Produces a sorted array of unique elements from a particular axis of the
+ * triplets array.  The filters are used to focus on particular coordinates
+ * of other axes as necessary.  The epsilons are used to constrain the
+ * equality of unique elements.
+ */
+static uint GetUniquelySortedElems(const uint m, const float *triplets, const int axis,
+    const double *const (&filters)[3], const double (&epsilons)[3], float *elems)
+{
+    uint count{0u};
+    for(uint i{0u};i < 3*m;i += 3)
+    {
+        const float elem{triplets[i + axis]};
+
+        uint j;
+        for(j = 0;j < 3;j++)
+        {
+            if(filters[j] && std::fabs(triplets[i + j] - *filters[j]) > epsilons[j])
+                break;
+        }
+        if(j < 3)
+            continue;
+
+        for(j = 0;j < count;j++)
+        {
+            const float delta{elem - elems[j]};
+
+            if(delta > epsilons[axis])
+                continue;
+
+            if(delta >= -epsilons[axis])
+                break;
+
+            for(uint k{count};k > j;k--)
+                elems[k] = elems[k - 1];
+
+            elems[j] = elem;
+            count++;
+            break;
+        }
+
+        if(j >= count)
+            elems[count++] = elem;
+    }
+
+    return count;
+}
+
+/* Given a list of elements, this will produce the smallest step size that
+ * can uniformly cover a fair portion of the list.  Ideally this will be over
+ * half, but in degenerate cases this can fall to a minimum of 5 (the lower
+ * limit on elevations necessary to build a layout).
+ */
+static float GetUniformStepSize(const double epsilon, const uint m, const float *elems)
+{
+    auto steps = std::vector<float>(m, 0.0f);
+    auto counts = std::vector<uint>(m, 0u);
+    float step{0.0f};
+    uint count{0u};
+
+    for(uint stride{1u};stride < m/2;stride++)
+    {
+        for(uint i{0u};i < m-stride;i++)
+        {
+            const float step{elems[i + stride] - elems[i]};
+
+            uint j;
+            for(j = 0;j < count;j++)
+            {
+                if(std::fabs(step - steps[j]) < epsilon)
+                {
+                    counts[j]++;
+                    break;
+                }
+            }
+
+            if(j >= count)
+            {
+                steps[j] = step;
+                counts[j] = 1;
+                count++;
+            }
+        }
+
+        for(uint i{1u};i < count;i++)
+        {
+            if(counts[i] > counts[0])
+            {
+                steps[0] = steps[i];
+                counts[0] = counts[i];
+            }
+        }
+
+        count = 1;
+
+        if(counts[0] > m/2)
+        {
+            step = steps[0];
+            return step;
+        }
+    }
+
+    if(counts[0] > 5)
+        step = steps[0];
+    return step;
+}
+
+/* Attempts to produce a compatible layout.  Most data sets tend to be
+ * uniform and have the same major axis as used by OpenAL Soft's HRTF model.
+ * This will remove outliers and produce a maximally dense layout when
+ * possible.  Those sets that contain purely random measurements or use
+ * different major axes will fail.
+ */
+static bool PrepareLayout(const uint m, const float *xyzs, HrirDataT *hData)
+{
+    std::vector<float> aers(3*m, 0.0f);
+    std::vector<float> elems(m, 0.0f);
+
+    for(uint i{0u};i < 3*m;i += 3)
+    {
+        aers[i] = xyzs[i];
+        aers[i + 1] = xyzs[i + 1];
+        aers[i + 2] = xyzs[i + 2];
+        mysofa_c2s(&aers[i]);
+    }
+
+    const uint fdCount{GetUniquelySortedElems(m, aers.data(), 2,
+        (const double*[3]){ nullptr, nullptr, nullptr }, (const double[3]){ 0.1, 0.1, 0.001 },
+        elems.data())};
+    if(fdCount > MAX_FD_COUNT)
+    {
+        fprintf(stdout, "Incompatible layout (inumerable radii).\n");
+        return false;
+    }
+
+    double distances[MAX_FD_COUNT]{};
+    uint evCounts[MAX_FD_COUNT]{};
+    uint evStarts[MAX_FD_COUNT]{};
+    auto azCounts = std::vector<uint>(MAX_FD_COUNT * MAX_EV_COUNT);
+    for(uint fi{0u};fi < fdCount;fi++)
+    {
+        distances[fi] = elems[fi];
+        if(fi > 0 && distances[fi] <= distances[fi-1])
+        {
+            fprintf(stderr, "Distances must increase.\n");
+            return 0;
+        }
+    }
+    if(distances[0] < hData->mRadius)
+    {
+        fprintf(stderr, "Distance cannot start below head radius.\n");
+        return 0;
+    }
+
+    for(uint fi{0u};fi < fdCount;fi++)
+    {
+        const double dist{distances[fi]};
+        uint evCount{GetUniquelySortedElems(m, aers.data(), 1,
+            (const double*[3]){ nullptr, nullptr, &dist }, (const double[3]){ 0.1, 0.1, 0.001 },
+            elems.data())};
+
+        if(evCount > MAX_EV_COUNT)
+        {
+            fprintf(stderr, "Incompatible layout (innumerable elevations).\n");
+            return false;
+        }
+
+        float step{GetUniformStepSize(0.1, evCount, elems.data())};
+        if(step <= 0.0f)
+        {
+            fprintf(stderr, "Incompatible layout (non-uniform elevations).\n");
+            return false;
+        }
+
+        uint evStart{0u};
+        for(uint ei{0u};ei < evCount;ei++)
+        {
+            float ev{90.0f + elems[ei]};
+            float eif{std::round(ev / step)};
+
+            if(std::fabs(eif - (uint)eif) < (0.1f / step))
+            {
+                evStart = static_cast<uint>(eif);
+                break;
+            }
+        }
+
+        evCount = static_cast<uint>(std::round(180.0f / step)) + 1;
+        if(evCount < 5)
+        {
+            fprintf(stderr, "Incompatible layout (too few uniform elevations).\n");
+            return false;
+        }
+
+        evCounts[fi] = evCount;
+        evStarts[fi] = evStart;
+
+        for(uint ei{evStart};ei < evCount;ei++)
+        {
+            const double ev{-90.0 + ei*180.0/(evCount - 1)};
+            const uint azCount{GetUniquelySortedElems(m, aers.data(), 0,
+                (const double*[3]){ nullptr, &ev, &dist }, (const double[3]){ 0.1, 0.1, 0.001 },
+                elems.data())};
+
+            if(azCount > MAX_AZ_COUNT)
+            {
+                fprintf(stderr, "Incompatible layout (innumerable azimuths).\n");
+                return false;
+            }
+
+            if(ei > 0 && ei < (evCount - 1))
+            {
+                step = GetUniformStepSize(0.1, azCount, elems.data());
+                if(step <= 0.0f)
+                {
+                    fprintf(stderr, "Incompatible layout (non-uniform azimuths).\n");
+                    return false;
+                }
+
+                azCounts[fi*MAX_EV_COUNT + ei] = static_cast<uint>(std::round(360.0f / step));
+            }
+            else if(azCount != 1)
+            {
+                fprintf(stderr, "Incompatible layout (non-singular poles).\n");
+                return false;
+            }
+            else
+            {
+                azCounts[fi*MAX_EV_COUNT + ei] = 1;
+            }
+        }
+
+        for(uint ei{0u};ei < evStart;ei++)
+            azCounts[fi*MAX_EV_COUNT + ei] = azCounts[fi*MAX_EV_COUNT + evCount - ei - 1];
+    }
+    return PrepareHrirData(fdCount, distances, evCounts, azCounts.data(), hData) != 0;
+}
+
+
+bool PrepareSampleRate(MYSOFA_HRTF *sofaHrtf, HrirDataT *hData)
+{
+    const char *srate_dim{nullptr};
+    const char *srate_units{nullptr};
+    MYSOFA_ARRAY *srate_array{&sofaHrtf->DataSamplingRate};
+    MYSOFA_ATTRIBUTE *srate_attrs{srate_array->attributes};
+    while(srate_attrs)
+    {
+        if(std::string{"DIMENSION_LIST"} == srate_attrs->name)
+        {
+            if(srate_dim)
+            {
+                fprintf(stderr, "Duplicate SampleRate.DIMENSION_LIST\n");
+                return false;
+            }
+            srate_dim = srate_attrs->value;
+        }
+        else if(std::string{"Units"} == srate_attrs->name)
+        {
+            if(srate_units)
+            {
+                fprintf(stderr, "Duplicate SampleRate.Units\n");
+                return false;
+            }
+            srate_units = srate_attrs->value;
+        }
+        else
+            fprintf(stderr, "Unexpected sample rate attribute: %s = %s\n", srate_attrs->name,
+                srate_attrs->value);
+        srate_attrs = srate_attrs->next;
+    }
+    if(!srate_dim)
+    {
+        fprintf(stderr, "Missing sample rate dimensions\n");
+        return false;
+    }
+    if(srate_dim != std::string{"I"})
+    {
+        fprintf(stderr, "Unsupported sample rate dimensions: %s\n", srate_dim);
+        return false;
+    }
+    if(!srate_units)
+    {
+        fprintf(stderr, "Missing sample rate unit type\n");
+        return false;
+    }
+    if(srate_units != std::string{"hertz"})
+    {
+        fprintf(stderr, "Unsupported sample rate unit type: %s\n", srate_units);
+        return false;
+    }
+    /* I dimensions guarantees 1 element, so just extract it. */
+    hData->mIrRate = static_cast<uint>(srate_array->values[0] + 0.5f);
+    if(hData->mIrRate < MIN_RATE || hData->mIrRate > MAX_RATE)
+    {
+        fprintf(stderr, "Sample rate out of range: %u (expected %u to %u)", hData->mIrRate,
+            MIN_RATE, MAX_RATE);
+        return false;
+    }
+    return true;
+}
+
+bool PrepareDelay(MYSOFA_HRTF *sofaHrtf, HrirDataT *hData)
+{
+    const char *delay_dim{nullptr};
+    MYSOFA_ARRAY *delay_array{&sofaHrtf->DataDelay};
+    MYSOFA_ATTRIBUTE *delay_attrs{delay_array->attributes};
+    while(delay_attrs)
+    {
+        if(std::string{"DIMENSION_LIST"} == delay_attrs->name)
+        {
+            if(delay_dim)
+            {
+                fprintf(stderr, "Duplicate Delay.DIMENSION_LIST\n");
+                return false;
+            }
+            delay_dim = delay_attrs->value;
+        }
+        else
+            fprintf(stderr, "Unexpected delay attribute: %s = %s\n", delay_attrs->name,
+                delay_attrs->value);
+        delay_attrs = delay_attrs->next;
+    }
+    if(!delay_dim)
+    {
+        fprintf(stderr, "Missing delay dimensions\n");
+        /*return false;*/
+    }
+    else if(delay_dim != std::string{"I,R"})
+    {
+        fprintf(stderr, "Unsupported delay dimensions: %s\n", delay_dim);
+        return false;
+    }
+    else if(hData->mChannelType == CT_STEREO)
+    {
+        /* I,R is 1xChannelCount. Makemhr currently removes any delay constant,
+         * so we can ignore this as long as it's equal.
+         */
+        if(delay_array->values[0] != delay_array->values[1])
+        {
+            fprintf(stderr, "Mismatched delays not supported: %f, %f\n", delay_array->values[0],
+                delay_array->values[1]);
+            return false;
+        }
+    }
+    return true;
+}
+
+bool CheckIrData(MYSOFA_HRTF *sofaHrtf)
+{
+    const char *ir_dim{nullptr};
+    MYSOFA_ARRAY *ir_array{&sofaHrtf->DataIR};
+    MYSOFA_ATTRIBUTE *ir_attrs{ir_array->attributes};
+    while(ir_attrs)
+    {
+        if(std::string{"DIMENSION_LIST"} == ir_attrs->name)
+        {
+            if(ir_dim)
+            {
+                fprintf(stderr, "Duplicate IR.DIMENSION_LIST\n");
+                return false;
+            }
+            ir_dim = ir_attrs->value;
+        }
+        else
+            fprintf(stderr, "Unexpected IR attribute: %s = %s\n", ir_attrs->name,
+                ir_attrs->value);
+        ir_attrs = ir_attrs->next;
+    }
+    if(!ir_dim)
+    {
+        fprintf(stderr, "Missing IR dimensions\n");
+        /*return false;*/
+    }
+    else if(ir_dim != std::string{"M,R,N"})
+    {
+        fprintf(stderr, "Unsupported IR dimensions: %s\n", ir_dim);
+        return false;
+    }
+    return true;
+}
+
+
+/* Calculate the onset time of a HRIR. */
+static double CalcHrirOnset(const uint rate, const uint n, const double *hrir)
+{
+    std::vector<double> upsampled(10 * n);
+    {
+        ResamplerT rs;
+        ResamplerSetup(&rs, rate, 10 * rate);
+        ResamplerRun(&rs, n, hrir, 10 * n, upsampled.data());
+    }
+
+    double mag{0.0};
+    for(uint i{0u};i < 10*n;i++)
+        mag = std::max(std::abs(upsampled[i]), mag);
+
+    mag *= 0.15;
+    uint i{0u};
+    for(;i < 10*n;i++)
+    {
+        if(std::abs(upsampled[i]) >= mag)
+            break;
+    }
+    return static_cast<double>(i) / (10*rate);
+}
+
+/* Calculate the magnitude response of a HRIR. */
+static void CalcHrirMagnitude(const uint points, const uint n, const double *hrir, double *mag)
+{
+    const uint m{1u + (n / 2u)};
+    auto h = std::vector<complex_d>(n);
+    auto r = std::vector<double>(n);
+
+    uint i{0u};
+    for(;i < points;i++)
+        h[i] = complex_d{hrir[i], 0.0};
+    for(;i < n;i++)
+        h[i] = complex_d{0.0, 0.0};
+    FftForward(n, h.data());
+    MagnitudeResponse(n, h.data(), r.data());
+    std::copy_n(r.begin(), m, mag);
+}
+
+
+struct MySofaHrtfDeleter {
+    void operator()(MYSOFA_HRTF *ptr) { mysofa_free(ptr); }
+};
+using MySofaHrtfPtr = std::unique_ptr<MYSOFA_HRTF,MySofaHrtfDeleter>;
+
+bool LoadSofaFile(const char *filename, const uint fftSize, const uint truncSize,
+    const ChannelModeT chanMode, HrirDataT *hData)
+{
+    int err;
+    MySofaHrtfPtr sofaHrtf{mysofa_load(filename, &err)};
+    if(!sofaHrtf)
+    {
+        fprintf(stdout, "Error: Could not load %s: %s\n", filename, SofaErrorStr(err));
+        return false;
+    }
+
+    err = mysofa_check(sofaHrtf.get());
+    if(err != MYSOFA_OK)
+/* NOTE: Some valid SOFA files are failing this check.
+    {
+        fprintf(stdout, "Error: Malformed source file '%s' (%s).\n", filename, SofaErrorStr(err));
+        return false;
+    }
+*/
+        fprintf(stderr, "Warning: Supposedly malformed source file '%s' (%s).\n", filename,
+            SofaErrorStr(err));
+
+    mysofa_tocartesian(sofaHrtf.get());
+
+    /* Make sure emitter and receiver counts are sane. */
+    if(sofaHrtf->E != 1)
+    {
+        fprintf(stderr, "%u emitters not supported\n", sofaHrtf->E);
+        return false;
+    }
+    if(sofaHrtf->R > 2 || sofaHrtf->R < 1)
+    {
+        fprintf(stderr, "%u receivers not supported\n", sofaHrtf->R);
+        return false;
+    }
+    /* Assume R=2 is a stereo measurement, and R=1 is mono left-ear-only. */
+    if(sofaHrtf->R == 2 && chanMode == CM_AllowStereo)
+        hData->mChannelType = CT_STEREO;
+    else
+        hData->mChannelType = CT_MONO;
+
+    /* Check and set the FFT and IR size. */
+    if(fftSize > 0 && sofaHrtf->N > fftSize)
+    {
+        fprintf(stderr, "Sample points exceeds the FFT size.\n");
+        return false;
+    }
+    if(sofaHrtf->N < truncSize)
+    {
+        fprintf(stderr, "Sample points is below the truncation size.\n");
+        return false;
+    }
+    hData->mIrPoints = sofaHrtf->N;
+    hData->mFftSize = fftSize;
+    hData->mIrSize = 1 + (fftSize / 2);
+    if(sofaHrtf->N > hData->mIrSize)
+        hData->mIrSize = sofaHrtf->N;
+
+    /* Assume a default head radius of 9cm. */
+    hData->mRadius = 0.09;
+
+    if(!PrepareSampleRate(sofaHrtf.get(), hData) || !PrepareDelay(sofaHrtf.get(), hData) ||
+       !CheckIrData(sofaHrtf.get()))
+        return false;
+    if(!PrepareLayout(sofaHrtf->M, sofaHrtf->SourcePosition.values, hData))
+        return false;
+
+    const uint channels{(hData->mChannelType == CT_STEREO) ? 2u : 1u};
+    hData->mHrirsBase.resize(channels * hData->mIrCount * hData->mIrSize);
+    double *hrirs = hData->mHrirsBase.data();
+    auto hrir = std::vector<double>(hData->mFftSize);
+    for(uint si{0u};si < sofaHrtf->M;si++)
+    {
+        printf("\rLoading HRIRs... %d of %d", si+1, sofaHrtf->M);
+        fflush(stdout);
+
+        float aer[3]{
+            sofaHrtf->SourcePosition.values[3*si],
+            sofaHrtf->SourcePosition.values[3*si + 1],
+            sofaHrtf->SourcePosition.values[3*si + 2]
+        };
+        mysofa_c2s(aer);
+
+        if(std::fabs(aer[1]) >= 89.999f)
+            aer[0] = 0.0f;
+        else
+            aer[0] = std::fmod(360.0f - aer[0], 360.0f);
+
+        uint fi{0u};
+        for(;fi < hData->mFdCount;++fi)
+        {
+            double delta = aer[2] - hData->mFds[fi].mDistance;
+            if(std::abs(delta) < 0.001) break;
+        }
+        if(fi >= hData->mFdCount)
+            continue;
+
+        double ef{(90.0+aer[1]) * (hData->mFds[fi].mEvCount-1) / 180.0};
+        auto ei = static_cast<int>(std::round(ef));
+        ef = (ef-ei) * 180.0f / (hData->mFds[fi].mEvCount-1);
+        if(std::abs(ef) >= 0.1) continue;
+
+        double af{aer[0] * hData->mFds[fi].mEvs[ei].mAzCount / 360.0f};
+        auto ai = static_cast<int>(std::round(af));
+        af = (af-ai) * 360.0f / hData->mFds[fi].mEvs[ei].mAzCount;
+        ai %= hData->mFds[fi].mEvs[ei].mAzCount;
+        if(std::abs(af) >= 0.1) continue;
+
+        HrirAzT *azd = &hData->mFds[fi].mEvs[ei].mAzs[ai];
+        if(azd->mIrs[0] != nullptr)
+        {
+            fprintf(stderr, "Multiple definitions of [ %d, %d, %d ].\n", fi, ei, ai);
+            return 0;
+        }
+
+        for(uint ti{0u};ti < channels;++ti)
+        {
+            std::copy_n(&sofaHrtf->DataIR.values[(si*sofaHrtf->R + ti)*sofaHrtf->N],
+                hData->mIrPoints, hrir.begin());
+            azd->mIrs[ti] = &hrirs[hData->mIrSize * (hData->mIrCount*ti + azd->mIndex)];
+            azd->mDelays[ti] = CalcHrirOnset(hData->mIrRate, hData->mIrPoints, hrir.data());
+            CalcHrirMagnitude(hData->mIrPoints, hData->mFftSize, hrir.data(), azd->mIrs[ti]);
+        }
+
+        // TODO: Since some SOFA files contain minimum phase HRIRs,
+        // it would be beneficial to check for per-measurement delays
+        // (when available) to reconstruct the HRTDs.
+    }
+    sofaHrtf = nullptr;
+    printf("\n");
+
+    for(uint fi{0u};fi < hData->mFdCount;fi++)
+    {
+        uint ei{0u};
+        for(;ei < hData->mFds[fi].mEvCount;ei++)
+        {
+            uint ai{0u};
+            for(;ai < hData->mFds[fi].mEvs[ei].mAzCount;ai++)
+            {
+                HrirAzT &azd = hData->mFds[fi].mEvs[ei].mAzs[ai];
+                if(azd.mIrs[0] != nullptr) break;
+            }
+            if(ai < hData->mFds[fi].mEvs[ei].mAzCount)
+                break;
+        }
+        if(ei >= hData->mFds[fi].mEvCount)
+        {
+            fprintf(stderr, "Missing source references [ %d, *, * ].\n", fi);
+            return false;
+        }
+        hData->mFds[fi].mEvStart = ei;
+        for(;ei < hData->mFds[fi].mEvCount;ei++)
+        {
+            for(uint ai{0u};ai < hData->mFds[fi].mEvs[ei].mAzCount;ai++)
+            {
+                HrirAzT &azd = hData->mFds[fi].mEvs[ei].mAzs[ai];
+                if(azd.mIrs[0] == nullptr)
+                {
+                    fprintf(stderr, "Missing source reference [ %d, %d, %d ].\n", fi, ei, ai);
+                    return false;
+                }
+            }
+        }
+    }
+    for(uint fi{0u};fi < hData->mFdCount;fi++)
+    {
+        for(uint ei{0u};ei < hData->mFds[fi].mEvCount;ei++)
+        {
+            for(uint ai{0u};ai < hData->mFds[fi].mEvs[ei].mAzCount;ai++)
+            {
+                HrirAzT &azd = hData->mFds[fi].mEvs[ei].mAzs[ai];
+                for(uint ti{0u};ti < channels;ti++)
+                    azd.mIrs[ti] = &hrirs[hData->mIrSize * (hData->mIrCount*ti + azd.mIndex)];
+            }
+        }
+    }
+
+    return true;
+}
diff --git a/utils/makemhr/loadsofa.h b/utils/makemhr/loadsofa.h
index 9a73bd72..93bf1704 100644
--- a/utils/makemhr/loadsofa.h
+++ b/utils/makemhr/loadsofa.h
@@ -3,4 +3,8 @@
 
 #include "makemhr.h"
 
+
+bool LoadSofaFile(const char *filename, const uint fftSize, const uint truncSize,
+    const ChannelModeT chanMode, HrirDataT *hData);
+
 #endif /* LOADSOFA_H */
diff --git a/utils/makemhr/makemhr.cpp b/utils/makemhr/makemhr.cpp
index 6824c542..4406384a 100644
--- a/utils/makemhr/makemhr.cpp
+++ b/utils/makemhr/makemhr.cpp
@@ -1475,7 +1475,9 @@ static void CalculateHrtds(const HeadModelT model, const double radius, HrirData
 }
 
 // Allocate and configure dynamic HRIR structures.
-int PrepareHrirData(const uint fdCount, const double distances[MAX_FD_COUNT], const uint evCounts[MAX_FD_COUNT], const uint azCounts[MAX_FD_COUNT * MAX_EV_COUNT], HrirDataT *hData)
+int PrepareHrirData(const uint fdCount, const double (&distances)[MAX_FD_COUNT],
+    const uint (&evCounts)[MAX_FD_COUNT], const uint azCounts[MAX_FD_COUNT * MAX_EV_COUNT],
+    HrirDataT *hData)
 {
     uint evTotal = 0, azTotal = 0, fi, ei, ai;
 
@@ -1566,8 +1568,11 @@ static int ProcessDefinition(const char *inName, const uint outRate, const Chann
            startbytes[3] == 'F')
         {
             fclose(fp);
-            fprintf(stderr, "Error: Direct SOFA input not yet supported\n");
-            return 0;
+            fp = nullptr;
+
+            fprintf(stdout, "Reading HRTF data from %s...\n", inName);
+            if(!LoadSofaFile(inName, fftSize, truncSize, chanMode, &hData))
+                return 0;
         }
     }
     if(fp != nullptr)
diff --git a/utils/makemhr/makemhr.h b/utils/makemhr/makemhr.h
index 047813d8..24520bd2 100644
--- a/utils/makemhr/makemhr.h
+++ b/utils/makemhr/makemhr.h
@@ -102,7 +102,7 @@ struct HrirDataT {
 };
 
 
-int PrepareHrirData(const uint fdCount, const double distances[MAX_FD_COUNT], const uint evCounts[MAX_FD_COUNT], const uint azCounts[MAX_FD_COUNT * MAX_EV_COUNT], HrirDataT *hData);
+int PrepareHrirData(const uint fdCount, const double (&distances)[MAX_FD_COUNT], const uint (&evCounts)[MAX_FD_COUNT], const uint azCounts[MAX_FD_COUNT * MAX_EV_COUNT], HrirDataT *hData);
 void MagnitudeResponse(const uint n, const complex_d *in, double *out);
 void FftForward(const uint n, complex_d *inout);
 void FftInverse(const uint n, complex_d *inout);