Merge branch 'v1.19' of git://repo.or.cz/openal-soft into v1.19v1.19

1 files changed, 543 insertions, 0 deletions

diff --git a/Alc/mastering.c b/Alc/mastering.c
new file mode 100644
index 00000000..6745c1c7
--- /dev/null
+++ b/Alc/mastering.c
@@ -0,0 +1,543 @@
+#include "config.h"
+
+#include <math.h>
+
+#include "mastering.h"
+#include "alu.h"
+#include "almalloc.h"
+#include "static_assert.h"
+#include "math_defs.h"
+
+
+/* Early MSVC lacks round/roundf */
+#if defined(_MSC_VER) && _MSC_VER < 1800
+static double round(double val)
+{
+    if(val < 0.0)
+        return ceil(val-0.5);
+    return floor(val+0.5);
+}
+#define roundf(f) ((float)round((float)(f)))
+#endif
+
+
+/* These structures assume BUFFERSIZE is a power of 2. */
+static_assert((BUFFERSIZE & (BUFFERSIZE-1)) == 0, "BUFFERSIZE is not a power of 2");
+
+typedef struct SlidingHold {
+    ALfloat Values[BUFFERSIZE];
+    ALsizei Expiries[BUFFERSIZE];
+    ALsizei LowerIndex;
+    ALsizei UpperIndex;
+    ALsizei Length;
+} SlidingHold;
+
+/* General topology and basic automation was based on the following paper:
+ *
+ *   D. Giannoulis, M. Massberg and J. D. Reiss,
+ *   "Parameter Automation in a Dynamic Range Compressor,"
+ *   Journal of the Audio Engineering Society, v61 (10), Oct. 2013
+ *
+ * Available (along with supplemental reading) at:
+ *
+ *   http://c4dm.eecs.qmul.ac.uk/audioengineering/compressors/
+ */
+typedef struct Compressor {
+    ALsizei NumChans;
+    ALuint SampleRate;
+
+    struct {
+        ALuint Knee : 1;
+        ALuint Attack : 1;
+        ALuint Release : 1;
+        ALuint PostGain : 1;
+        ALuint Declip : 1;
+    } Auto;
+
+    ALsizei LookAhead;
+
+    ALfloat PreGain;
+    ALfloat PostGain;
+
+    ALfloat Threshold;
+    ALfloat Slope;
+    ALfloat Knee;
+
+    ALfloat Attack;
+    ALfloat Release;
+
+    alignas(16) ALfloat SideChain[2*BUFFERSIZE];
+    alignas(16) ALfloat CrestFactor[BUFFERSIZE];
+
+    SlidingHold *Hold;
+    ALfloat (*Delay)[BUFFERSIZE];
+    ALsizei DelayIndex;
+
+    ALfloat CrestCoeff;
+    ALfloat GainEstimate;
+    ALfloat AdaptCoeff;
+
+    ALfloat LastPeakSq;
+    ALfloat LastRmsSq;
+    ALfloat LastRelease;
+    ALfloat LastAttack;
+    ALfloat LastGainDev;
+} Compressor;
+
+
+/* This sliding hold follows the input level with an instant attack and a
+ * fixed duration hold before an instant release to the next highest level.
+ * It is a sliding window maximum (descending maxima) implementation based on
+ * Richard Harter's ascending minima algorithm available at:
+ *
+ *   http://www.richardhartersworld.com/cri/2001/slidingmin.html
+ */
+static ALfloat UpdateSlidingHold(SlidingHold *Hold, const ALsizei i, const ALfloat in)
+{
+    const ALsizei mask = BUFFERSIZE - 1;
+    const ALsizei length = Hold->Length;
+    ALfloat *restrict values = Hold->Values;
+    ALsizei *restrict expiries = Hold->Expiries;
+    ALsizei lowerIndex = Hold->LowerIndex;
+    ALsizei upperIndex = Hold->UpperIndex;
+
+    if(i >= expiries[upperIndex])
+        upperIndex = (upperIndex + 1) & mask;
+
+    if(in >= values[upperIndex])
+    {
+        values[upperIndex] = in;
+        expiries[upperIndex] = i + length;
+        lowerIndex = upperIndex;
+    }
+    else
+    {
+        do {
+            do {
+                if(!(in >= values[lowerIndex]))
+                    goto found_place;
+            } while(lowerIndex--);
+            lowerIndex = mask;
+        } while(1);
+    found_place:
+
+        lowerIndex = (lowerIndex + 1) & mask;
+        values[lowerIndex] = in;
+        expiries[lowerIndex] = i + length;
+    }
+
+    Hold->LowerIndex = lowerIndex;
+    Hold->UpperIndex = upperIndex;
+
+    return values[upperIndex];
+}
+
+static void ShiftSlidingHold(SlidingHold *Hold, const ALsizei n)
+{
+    const ALsizei lowerIndex = Hold->LowerIndex;
+    ALsizei *restrict expiries = Hold->Expiries;
+    ALsizei i = Hold->UpperIndex;
+
+    if(lowerIndex < i)
+    {
+        for(;i < BUFFERSIZE;i++)
+            expiries[i] -= n;
+        i = 0;
+    }
+    for(;i < lowerIndex;i++)
+        expiries[i] -= n;
+
+    expiries[i] -= n;
+}
+
+/* Multichannel compression is linked via the absolute maximum of all
+ * channels.
+ */
+static void LinkChannels(Compressor *Comp, const ALsizei SamplesToDo, ALfloat (*restrict OutBuffer)[BUFFERSIZE])
+{
+    const ALsizei index = Comp->LookAhead;
+    const ALsizei numChans = Comp->NumChans;
+    ALfloat *restrict sideChain = Comp->SideChain;
+    ALsizei c, i;
+
+    ASSUME(SamplesToDo > 0);
+    ASSUME(numChans > 0);
+
+    for(i = 0;i < SamplesToDo;i++)
+        sideChain[index + i] = 0.0f;
+
+    for(c = 0;c < numChans;c++)
+    {
+        ALsizei offset = index;
+        for(i = 0;i < SamplesToDo;i++)
+        {
+            sideChain[offset] = maxf(sideChain[offset], fabsf(OutBuffer[c][i]));
+            ++offset;
+        }
+    }
+}
+
+/* This calculates the squared crest factor of the control signal for the
+ * basic automation of the attack/release times.  As suggested by the paper,
+ * it uses an instantaneous squared peak detector and a squared RMS detector
+ * both with 200ms release times.
+ */
+static void CrestDetector(Compressor *Comp, const ALsizei SamplesToDo)
+{
+    const ALfloat a_crest = Comp->CrestCoeff;
+    const ALsizei index = Comp->LookAhead;
+    const ALfloat *restrict sideChain = Comp->SideChain;
+    ALfloat *restrict crestFactor = Comp->CrestFactor;
+    ALfloat y2_peak = Comp->LastPeakSq;
+    ALfloat y2_rms = Comp->LastRmsSq;
+    ALsizei i;
+
+    ASSUME(SamplesToDo > 0);
+
+    for(i = 0;i < SamplesToDo;i++)
+    {
+        ALfloat x_abs = sideChain[index + i];
+        ALfloat x2 = maxf(0.000001f, x_abs * x_abs);
+
+        y2_peak = maxf(x2, lerp(x2, y2_peak, a_crest));
+        y2_rms = lerp(x2, y2_rms, a_crest);
+        crestFactor[i] = y2_peak / y2_rms;
+    }
+
+    Comp->LastPeakSq = y2_peak;
+    Comp->LastRmsSq = y2_rms;
+}
+
+/* The side-chain starts with a simple peak detector (based on the absolute
+ * value of the incoming signal) and performs most of its operations in the
+ * log domain.
+ */
+static void PeakDetector(Compressor *Comp, const ALsizei SamplesToDo)
+{
+    const ALsizei index = Comp->LookAhead;
+    ALfloat *restrict sideChain = Comp->SideChain;
+    ALsizei i;
+
+    ASSUME(SamplesToDo > 0);
+
+    for(i = 0;i < SamplesToDo;i++)
+    {
+        const ALuint offset = index + i;
+        const ALfloat x_abs = sideChain[offset];
+
+        sideChain[offset] = logf(maxf(0.000001f, x_abs));
+    }
+}
+
+/* An optional hold can be used to extend the peak detector so it can more
+ * solidly detect fast transients.  This is best used when operating as a
+ * limiter.
+ */
+static void PeakHoldDetector(Compressor *Comp, const ALsizei SamplesToDo)
+{
+    const ALsizei index = Comp->LookAhead;
+    ALfloat *restrict sideChain = Comp->SideChain;
+    SlidingHold *hold = Comp->Hold;
+    ALsizei i;
+
+    ASSUME(SamplesToDo > 0);
+
+    for(i = 0;i < SamplesToDo;i++)
+    {
+        const ALsizei offset = index + i;
+        const ALfloat x_abs = sideChain[offset];
+        const ALfloat x_G = logf(maxf(0.000001f, x_abs));
+
+        sideChain[offset] = UpdateSlidingHold(hold, i, x_G);
+    }
+
+    ShiftSlidingHold(hold, SamplesToDo);
+}
+
+/* This is the heart of the feed-forward compressor.  It operates in the log
+ * domain (to better match human hearing) and can apply some basic automation
+ * to knee width, attack/release times, make-up/post gain, and clipping
+ * reduction.
+ */
+static void GainCompressor(Compressor *Comp, const ALsizei SamplesToDo)
+{
+    const bool autoKnee = Comp->Auto.Knee;
+    const bool autoAttack = Comp->Auto.Attack;
+    const bool autoRelease = Comp->Auto.Release;
+    const bool autoPostGain = Comp->Auto.PostGain;
+    const bool autoDeclip = Comp->Auto.Declip;
+    const ALsizei lookAhead = Comp->LookAhead;
+    const ALfloat threshold = Comp->Threshold;
+    const ALfloat slope = Comp->Slope;
+    const ALfloat attack = Comp->Attack;
+    const ALfloat release = Comp->Release;
+    const ALfloat c_est = Comp->GainEstimate;
+    const ALfloat a_adp = Comp->AdaptCoeff;
+    const ALfloat *restrict crestFactor = Comp->CrestFactor;
+    ALfloat *restrict sideChain = Comp->SideChain;
+    ALfloat postGain = Comp->PostGain;
+    ALfloat knee = Comp->Knee;
+    ALfloat t_att = attack;
+    ALfloat t_rel = release - attack;
+    ALfloat a_att = expf(-1.0f / t_att);
+    ALfloat a_rel = expf(-1.0f / t_rel);
+    ALfloat y_1 = Comp->LastRelease;
+    ALfloat y_L = Comp->LastAttack;
+    ALfloat c_dev = Comp->LastGainDev;
+    ALsizei i;
+
+    ASSUME(SamplesToDo > 0);
+
+    for(i = 0;i < SamplesToDo;i++)
+    {
+        const ALfloat y2_crest = crestFactor[i];
+        const ALfloat x_G = sideChain[lookAhead + i];
+        const ALfloat x_over = x_G - threshold;
+        ALfloat knee_h;
+        ALfloat y_G;
+        ALfloat x_L;
+
+        if(autoKnee)
+            knee = maxf(0.0f, 2.5f * (c_dev + c_est));
+        knee_h = 0.5f * knee;
+
+        /* This is the gain computer.  It applies a static compression curve
+         * to the control signal.
+         */
+        if(x_over <= -knee_h)
+            y_G = 0.0f;
+        else if(fabsf(x_over) < knee_h)
+            y_G = (x_over + knee_h) * (x_over + knee_h) / (2.0f * knee);
+        else
+            y_G = x_over;
+
+        x_L = -slope * y_G;
+
+        if(autoAttack)
+        {
+            t_att = 2.0f * attack / y2_crest;
+            a_att = expf(-1.0f / t_att);
+        }
+
+        if(autoRelease)
+        {
+            t_rel = 2.0f * release / y2_crest - t_att;
+            a_rel = expf(-1.0f / t_rel);
+        }
+
+        /* Gain smoothing (ballistics) is done via a smooth decoupled peak
+         * detector.  The attack time is subtracted from the release time
+         * above to compensate for the chained operating mode.
+         */
+        y_1 = maxf(x_L, lerp(x_L, y_1, a_rel));
+        y_L = lerp(y_1, y_L, a_att);
+
+        /* Knee width and make-up gain automation make use of a smoothed
+         * measurement of deviation between the control signal and estimate.
+         * The estimate is also used to bias the measurement to hot-start its
+         * average.
+         */
+        c_dev = lerp(-y_L - c_est, c_dev, a_adp);
+
+        if(autoPostGain)
+        {
+            /* Clipping reduction is only viable when make-up gain is being
+             * automated.  It modifies the deviation to further attenuate the
+             * control signal when clipping is detected.  The adaptation
+             * time is sufficiently long enough to suppress further clipping
+             * at the same output level.
+             */
+            if(autoDeclip)
+                c_dev = maxf(c_dev, sideChain[i] - y_L - threshold - c_est);
+
+            postGain = -(c_dev + c_est);
+        }
+
+        sideChain[i] = expf(postGain - y_L);
+    }
+
+    Comp->LastRelease = y_1;
+    Comp->LastAttack = y_L;
+    Comp->LastGainDev = c_dev;
+}
+
+/* Combined with the hold time, a look-ahead delay can improve handling of
+ * fast transients by allowing the envelope time to converge prior to
+ * reaching the offending impulse.  This is best used when operating as a
+ * limiter.
+ */
+static void SignalDelay(Compressor *Comp, const ALsizei SamplesToDo, ALfloat (*restrict OutBuffer)[BUFFERSIZE])
+{
+    const ALsizei mask = BUFFERSIZE - 1;
+    const ALsizei numChans = Comp->NumChans;
+    const ALsizei indexIn = Comp->DelayIndex;
+    const ALsizei indexOut = Comp->DelayIndex - Comp->LookAhead;
+    ALfloat (*restrict delay)[BUFFERSIZE] = Comp->Delay;
+    ALsizei c, i;
+
+    ASSUME(SamplesToDo > 0);
+    ASSUME(numChans > 0);
+
+    for(c = 0;c < numChans;c++)
+    {
+        for(i = 0;i < SamplesToDo;i++)
+        {
+            ALfloat sig = OutBuffer[c][i];
+
+            OutBuffer[c][i] = delay[c][(indexOut + i) & mask];
+            delay[c][(indexIn + i) & mask] = sig;
+        }
+    }
+
+    Comp->DelayIndex = (indexIn + SamplesToDo) & mask;
+}
+
+/* The compressor is initialized with the following settings:
+ *
+ *   NumChans       - Number of channels to process.
+ *   SampleRate     - Sample rate to process.
+ *   AutoKnee       - Whether to automate the knee width parameter.
+ *   AutoAttack     - Whether to automate the attack time parameter.
+ *   AutoRelease    - Whether to automate the release time parameter.
+ *   AutoPostGain   - Whether to automate the make-up (post) gain parameter.
+ *   AutoDeclip     - Whether to automate clipping reduction.  Ignored when
+ *                    not automating make-up gain.
+ *   LookAheadTime  - Look-ahead time (in seconds).
+ *   HoldTime       - Peak hold-time (in seconds).
+ *   PreGainDb      - Gain applied before detection (in dB).
+ *   PostGainDb     - Make-up gain applied after compression (in dB).
+ *   ThresholdDb    - Triggering threshold (in dB).
+ *   Ratio          - Compression ratio (x:1).  Set to INFINITY for true
+ *                    limiting.  Ignored when automating knee width.
+ *   KneeDb         - Knee width (in dB).  Ignored when automating knee
+ *                    width.
+ *   AttackTimeMin  - Attack time (in seconds).  Acts as a maximum when
+ *                    automating attack time.
+ *   ReleaseTimeMin - Release time (in seconds).  Acts as a maximum when
+ *                    automating release time.
+ */
+Compressor* CompressorInit(const ALsizei NumChans, const ALuint SampleRate,
+                           const ALboolean AutoKnee, const ALboolean AutoAttack,
+                           const ALboolean AutoRelease, const ALboolean AutoPostGain,
+                           const ALboolean AutoDeclip, const ALfloat LookAheadTime,
+                           const ALfloat HoldTime, const ALfloat PreGainDb,
+                           const ALfloat PostGainDb, const ALfloat ThresholdDb,
+                           const ALfloat Ratio, const ALfloat KneeDb,
+                           const ALfloat AttackTime, const ALfloat ReleaseTime)
+{
+    Compressor *Comp;
+    ALsizei lookAhead;
+    ALsizei hold;
+    size_t size;
+
+    lookAhead = (ALsizei)clampf(roundf(LookAheadTime*SampleRate), 0.0f, BUFFERSIZE-1);
+    hold = (ALsizei)clampf(roundf(HoldTime*SampleRate), 0.0f, BUFFERSIZE-1);
+    /* The sliding hold implementation doesn't handle a length of 1. A 1-sample
+     * hold is useless anyway, it would only ever give back what was just given
+     * to it.
+     */
+    if(hold == 1)
+        hold = 0;
+
+    size = sizeof(*Comp);
+    if(lookAhead > 0)
+    {
+        size += sizeof(*Comp->Delay) * NumChans;
+        if(hold > 0)
+            size += sizeof(*Comp->Hold);
+    }
+
+    Comp = al_calloc(16, size);
+    Comp->NumChans = NumChans;
+    Comp->SampleRate = SampleRate;
+    Comp->Auto.Knee = AutoKnee;
+    Comp->Auto.Attack = AutoAttack;
+    Comp->Auto.Release = AutoRelease;
+    Comp->Auto.PostGain = AutoPostGain;
+    Comp->Auto.Declip = AutoPostGain && AutoDeclip;
+    Comp->LookAhead = lookAhead;
+    Comp->PreGain = powf(10.0f, PreGainDb / 20.0f);
+    Comp->PostGain = PostGainDb * logf(10.0f) / 20.0f;
+    Comp->Threshold = ThresholdDb * logf(10.0f) / 20.0f;
+    Comp->Slope = 1.0f / maxf(1.0f, Ratio) - 1.0f;
+    Comp->Knee = maxf(0.0f, KneeDb * logf(10.0f) / 20.0f);
+    Comp->Attack = maxf(1.0f, AttackTime * SampleRate);
+    Comp->Release = maxf(1.0f, ReleaseTime * SampleRate);
+
+    /* Knee width automation actually treats the compressor as a limiter.  By
+     * varying the knee width, it can effectively be seen as applying
+     * compression over a wide range of ratios.
+     */
+    if(AutoKnee)
+        Comp->Slope = -1.0f;
+
+    if(lookAhead > 0)
+    {
+        if(hold > 0)
+        {
+            Comp->Hold = (SlidingHold*)(Comp + 1);
+            Comp->Hold->Values[0] = -HUGE_VALF;
+            Comp->Hold->Expiries[0] = hold;
+            Comp->Hold->Length = hold;
+            Comp->Delay = (ALfloat(*)[BUFFERSIZE])(Comp->Hold + 1);
+        }
+        else
+        {
+            Comp->Delay = (ALfloat(*)[BUFFERSIZE])(Comp + 1);
+        }
+    }
+
+    Comp->CrestCoeff = expf(-1.0f / (0.200f * SampleRate)); // 200ms
+    Comp->GainEstimate = Comp->Threshold * -0.5f * Comp->Slope;
+    Comp->AdaptCoeff = expf(-1.0f / (2.0f * SampleRate)); // 2s
+
+    return Comp;
+}
+
+void ApplyCompression(Compressor *Comp, const ALsizei SamplesToDo, ALfloat (*restrict OutBuffer)[BUFFERSIZE])
+{
+    const ALsizei numChans = Comp->NumChans;
+    const ALfloat preGain = Comp->PreGain;
+    ALfloat *restrict sideChain;
+    ALsizei c, i;
+
+    ASSUME(SamplesToDo > 0);
+    ASSUME(numChans > 0);
+
+    if(preGain != 1.0f)
+    {
+        for(c = 0;c < numChans;c++)
+        {
+            for(i = 0;i < SamplesToDo;i++)
+                OutBuffer[c][i] *= preGain;
+        }
+    }
+
+    LinkChannels(Comp, SamplesToDo, OutBuffer);
+
+    if(Comp->Auto.Attack || Comp->Auto.Release)
+        CrestDetector(Comp, SamplesToDo);
+
+    if(Comp->Hold)
+        PeakHoldDetector(Comp, SamplesToDo);
+    else
+        PeakDetector(Comp, SamplesToDo);
+
+    GainCompressor(Comp, SamplesToDo);
+
+    if(Comp->Delay)
+        SignalDelay(Comp, SamplesToDo, OutBuffer);
+
+    sideChain = Comp->SideChain;
+    for(c = 0;c < numChans;c++)
+    {
+        for(i = 0;i < SamplesToDo;i++)
+            OutBuffer[c][i] *= sideChain[i];
+    }
+
+    memmove(sideChain, sideChain+SamplesToDo, Comp->LookAhead*sizeof(ALfloat));
+}
+
+
+ALsizei GetCompressorLookAhead(const Compressor *Comp)
+{ return Comp->LookAhead; }