| /* ----------------------------------------------------------------------------- |
| Software License for The Fraunhofer FDK AAC Codec Library for Android |
| |
| © Copyright 1995 - 2018 Fraunhofer-Gesellschaft zur Förderung der angewandten |
| Forschung e.V. All rights reserved. |
| |
| 1. INTRODUCTION |
| The Fraunhofer FDK AAC Codec Library for Android ("FDK AAC Codec") is software |
| that implements the MPEG Advanced Audio Coding ("AAC") encoding and decoding |
| scheme for digital audio. This FDK AAC Codec software is intended to be used on |
| a wide variety of Android devices. |
| |
| AAC's HE-AAC and HE-AAC v2 versions are regarded as today's most efficient |
| general perceptual audio codecs. AAC-ELD is considered the best-performing |
| full-bandwidth communications codec by independent studies and is widely |
| deployed. AAC has been standardized by ISO and IEC as part of the MPEG |
| specifications. |
| |
| Patent licenses for necessary patent claims for the FDK AAC Codec (including |
| those of Fraunhofer) may be obtained through Via Licensing |
| (www.vialicensing.com) or through the respective patent owners individually for |
| the purpose of encoding or decoding bit streams in products that are compliant |
| with the ISO/IEC MPEG audio standards. Please note that most manufacturers of |
| Android devices already license these patent claims through Via Licensing or |
| directly from the patent owners, and therefore FDK AAC Codec software may |
| already be covered under those patent licenses when it is used for those |
| licensed purposes only. |
| |
| Commercially-licensed AAC software libraries, including floating-point versions |
| with enhanced sound quality, are also available from Fraunhofer. Users are |
| encouraged to check the Fraunhofer website for additional applications |
| information and documentation. |
| |
| 2. COPYRIGHT LICENSE |
| |
| Redistribution and use in source and binary forms, with or without modification, |
| are permitted without payment of copyright license fees provided that you |
| satisfy the following conditions: |
| |
| You must retain the complete text of this software license in redistributions of |
| the FDK AAC Codec or your modifications thereto in source code form. |
| |
| You must retain the complete text of this software license in the documentation |
| and/or other materials provided with redistributions of the FDK AAC Codec or |
| your modifications thereto in binary form. You must make available free of |
| charge copies of the complete source code of the FDK AAC Codec and your |
| modifications thereto to recipients of copies in binary form. |
| |
| The name of Fraunhofer may not be used to endorse or promote products derived |
| from this library without prior written permission. |
| |
| You may not charge copyright license fees for anyone to use, copy or distribute |
| the FDK AAC Codec software or your modifications thereto. |
| |
| Your modified versions of the FDK AAC Codec must carry prominent notices stating |
| that you changed the software and the date of any change. For modified versions |
| of the FDK AAC Codec, the term "Fraunhofer FDK AAC Codec Library for Android" |
| must be replaced by the term "Third-Party Modified Version of the Fraunhofer FDK |
| AAC Codec Library for Android." |
| |
| 3. NO PATENT LICENSE |
| |
| NO EXPRESS OR IMPLIED LICENSES TO ANY PATENT CLAIMS, including without |
| limitation the patents of Fraunhofer, ARE GRANTED BY THIS SOFTWARE LICENSE. |
| Fraunhofer provides no warranty of patent non-infringement with respect to this |
| software. |
| |
| You may use this FDK AAC Codec software or modifications thereto only for |
| purposes that are authorized by appropriate patent licenses. |
| |
| 4. DISCLAIMER |
| |
| This FDK AAC Codec software is provided by Fraunhofer on behalf of the copyright |
| holders and contributors "AS IS" and WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES, |
| including but not limited to the implied warranties of merchantability and |
| fitness for a particular purpose. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR |
| CONTRIBUTORS BE LIABLE for any direct, indirect, incidental, special, exemplary, |
| or consequential damages, including but not limited to procurement of substitute |
| goods or services; loss of use, data, or profits, or business interruption, |
| however caused and on any theory of liability, whether in contract, strict |
| liability, or tort (including negligence), arising in any way out of the use of |
| this software, even if advised of the possibility of such damage. |
| |
| 5. CONTACT INFORMATION |
| |
| Fraunhofer Institute for Integrated Circuits IIS |
| Attention: Audio and Multimedia Departments - FDK AAC LL |
| Am Wolfsmantel 33 |
| 91058 Erlangen, Germany |
| |
| www.iis.fraunhofer.de/amm |
| amm-info@iis.fraunhofer.de |
| ----------------------------------------------------------------------------- */ |
| |
| /**************************** PCM utility library ****************************** |
| |
| Author(s): Matthias Neusinger |
| |
| Description: Hard limiter for clipping prevention |
| |
| *******************************************************************************/ |
| |
| #include "limiter.h" |
| #include "FDK_core.h" |
| |
| /* library version */ |
| #include "version.h" |
| /* library title */ |
| #define TDLIMIT_LIB_TITLE "TD Limiter Lib" |
| |
| /* create limiter */ |
| TDLimiterPtr pcmLimiter_Create(unsigned int maxAttackMs, unsigned int releaseMs, |
| FIXP_DBL threshold, unsigned int maxChannels, |
| UINT maxSampleRate) { |
| TDLimiterPtr limiter = NULL; |
| unsigned int attack, release; |
| FIXP_DBL attackConst, releaseConst, exponent; |
| INT e_ans; |
| |
| /* calc attack and release time in samples */ |
| attack = (unsigned int)(maxAttackMs * maxSampleRate / 1000); |
| release = (unsigned int)(releaseMs * maxSampleRate / 1000); |
| |
| /* alloc limiter struct */ |
| limiter = (TDLimiterPtr)FDKcalloc(1, sizeof(struct TDLimiter)); |
| if (!limiter) return NULL; |
| |
| /* alloc max and delay buffers */ |
| limiter->maxBuf = (FIXP_DBL*)FDKcalloc(attack + 1, sizeof(FIXP_DBL)); |
| limiter->delayBuf = |
| (FIXP_DBL*)FDKcalloc(attack * maxChannels, sizeof(FIXP_DBL)); |
| |
| if (!limiter->maxBuf || !limiter->delayBuf) { |
| pcmLimiter_Destroy(limiter); |
| return NULL; |
| } |
| |
| /* attackConst = pow(0.1, 1.0 / (attack + 1)) */ |
| exponent = invFixp(attack + 1); |
| attackConst = fPow(FL2FXCONST_DBL(0.1f), 0, exponent, 0, &e_ans); |
| attackConst = scaleValue(attackConst, e_ans); |
| |
| /* releaseConst = (float)pow(0.1, 1.0 / (release + 1)) */ |
| exponent = invFixp(release + 1); |
| releaseConst = fPow(FL2FXCONST_DBL(0.1f), 0, exponent, 0, &e_ans); |
| releaseConst = scaleValue(releaseConst, e_ans); |
| |
| /* init parameters */ |
| limiter->attackMs = maxAttackMs; |
| limiter->maxAttackMs = maxAttackMs; |
| limiter->releaseMs = releaseMs; |
| limiter->attack = attack; |
| limiter->attackConst = attackConst; |
| limiter->releaseConst = releaseConst; |
| limiter->threshold = threshold >> TDL_GAIN_SCALING; |
| limiter->channels = maxChannels; |
| limiter->maxChannels = maxChannels; |
| limiter->sampleRate = maxSampleRate; |
| limiter->maxSampleRate = maxSampleRate; |
| |
| pcmLimiter_Reset(limiter); |
| |
| return limiter; |
| } |
| |
| /* apply limiter */ |
| TDLIMITER_ERROR pcmLimiter_Apply(TDLimiterPtr limiter, PCM_LIM* samplesIn, |
| INT_PCM* samplesOut, FIXP_DBL* RESTRICT pGain, |
| const INT* RESTRICT gain_scale, |
| const UINT gain_size, const UINT gain_delay, |
| const UINT nSamples) { |
| unsigned int i, j; |
| FIXP_DBL tmp1; |
| FIXP_DBL tmp2; |
| FIXP_DBL tmp, old, gain, additionalGain = 0, additionalGainUnfiltered; |
| FIXP_DBL minGain = FL2FXCONST_DBL(1.0f / (1 << 1)); |
| |
| FDK_ASSERT(gain_size == 1); |
| FDK_ASSERT(gain_delay <= nSamples); |
| |
| if (limiter == NULL) return TDLIMIT_INVALID_HANDLE; |
| |
| { |
| unsigned int channels = limiter->channels; |
| unsigned int attack = limiter->attack; |
| FIXP_DBL attackConst = limiter->attackConst; |
| FIXP_DBL releaseConst = limiter->releaseConst; |
| FIXP_DBL threshold = limiter->threshold; |
| |
| FIXP_DBL max = limiter->max; |
| FIXP_DBL* maxBuf = limiter->maxBuf; |
| unsigned int maxBufIdx = limiter->maxBufIdx; |
| FIXP_DBL cor = limiter->cor; |
| FIXP_DBL* delayBuf = limiter->delayBuf; |
| unsigned int delayBufIdx = limiter->delayBufIdx; |
| |
| FIXP_DBL smoothState0 = limiter->smoothState0; |
| FIXP_DBL additionalGainSmoothState = limiter->additionalGainFilterState; |
| FIXP_DBL additionalGainSmoothState1 = limiter->additionalGainFilterState1; |
| |
| if (!gain_delay) { |
| additionalGain = pGain[0]; |
| if (gain_scale[0] > 0) { |
| additionalGain <<= gain_scale[0]; |
| } else { |
| additionalGain >>= -gain_scale[0]; |
| } |
| } |
| |
| for (i = 0; i < nSamples; i++) { |
| if (gain_delay) { |
| if (i < gain_delay) { |
| additionalGainUnfiltered = limiter->additionalGainPrev; |
| } else { |
| additionalGainUnfiltered = pGain[0]; |
| } |
| |
| /* Smooth additionalGain */ |
| /* [b,a] = butter(1, 0.01) */ |
| static const FIXP_SGL b[] = {FL2FXCONST_SGL(0.015466 * 2.0), |
| FL2FXCONST_SGL(0.015466 * 2.0)}; |
| static const FIXP_SGL a[] = {(FIXP_SGL)MAXVAL_SGL, |
| FL2FXCONST_SGL(-0.96907)}; |
| additionalGain = -fMult(additionalGainSmoothState, a[1]) + |
| fMultDiv2(additionalGainUnfiltered, b[0]) + |
| fMultDiv2(additionalGainSmoothState1, b[1]); |
| additionalGainSmoothState1 = additionalGainUnfiltered; |
| additionalGainSmoothState = additionalGain; |
| |
| /* Apply the additional scaling that has no delay and no smoothing */ |
| if (gain_scale[0] > 0) { |
| additionalGain <<= gain_scale[0]; |
| } else { |
| additionalGain >>= -gain_scale[0]; |
| } |
| } |
| /* get maximum absolute sample value of all channels, including the |
| * additional gain. */ |
| tmp1 = (FIXP_DBL)0; |
| for (j = 0; j < channels; j++) { |
| tmp2 = PCM_LIM2FIXP_DBL(samplesIn[j]); |
| tmp2 = fAbs(tmp2); |
| tmp2 = FIXP_DBL(INT(tmp2) ^ INT((tmp2 >> (SAMPLE_BITS_LIM - 1)))); |
| tmp1 = fMax(tmp1, tmp2); |
| } |
| tmp = fMult(tmp1, additionalGain); |
| |
| /* set threshold as lower border to save calculations in running maximum |
| * algorithm */ |
| tmp = fMax(tmp, threshold); |
| |
| /* running maximum */ |
| old = maxBuf[maxBufIdx]; |
| maxBuf[maxBufIdx] = tmp; |
| |
| if (tmp >= max) { |
| /* new sample is greater than old maximum, so it is the new maximum */ |
| max = tmp; |
| } else if (old < max) { |
| /* maximum does not change, as the sample, which has left the window was |
| not the maximum */ |
| } else { |
| /* the old maximum has left the window, we have to search the complete |
| buffer for the new max */ |
| max = maxBuf[0]; |
| for (j = 1; j <= attack; j++) { |
| max = fMax(max, maxBuf[j]); |
| } |
| } |
| maxBufIdx++; |
| if (maxBufIdx >= attack + 1) maxBufIdx = 0; |
| |
| /* calc gain */ |
| /* gain is downscaled by one, so that gain = 1.0 can be represented */ |
| if (max > threshold) { |
| gain = fDivNorm(threshold, max) >> 1; |
| } else { |
| gain = FL2FXCONST_DBL(1.0f / (1 << 1)); |
| } |
| |
| /* gain smoothing, method: TDL_EXPONENTIAL */ |
| /* first order IIR filter with attack correction to avoid overshoots */ |
| |
| /* correct the 'aiming' value of the exponential attack to avoid the |
| * remaining overshoot */ |
| if (gain < smoothState0) { |
| cor = fMin(cor, |
| fMultDiv2((gain - fMultDiv2(FL2FXCONST_SGL(0.1f * (1 << 1)), |
| smoothState0)), |
| FL2FXCONST_SGL(1.11111111f / (1 << 1))) |
| << 2); |
| } else { |
| cor = gain; |
| } |
| |
| /* smoothing filter */ |
| if (cor < smoothState0) { |
| smoothState0 = |
| fMult(attackConst, (smoothState0 - cor)) + cor; /* attack */ |
| smoothState0 = fMax(smoothState0, gain); /* avoid overshooting target */ |
| } else { |
| /* sign inversion twice to round towards +infinity, |
| so that gain can converge to 1.0 again, |
| for bit-identical output when limiter is not active */ |
| smoothState0 = |
| -fMult(releaseConst, -(smoothState0 - cor)) + cor; /* release */ |
| } |
| |
| gain = smoothState0; |
| |
| FIXP_DBL* p_delayBuf = &delayBuf[delayBufIdx * channels + 0]; |
| if (gain < FL2FXCONST_DBL(1.0f / (1 << 1))) { |
| gain <<= 1; |
| /* lookahead delay, apply gain */ |
| for (j = 0; j < channels; j++) { |
| tmp = p_delayBuf[j]; |
| p_delayBuf[j] = fMult((FIXP_PCM_LIM)samplesIn[j], additionalGain); |
| |
| /* Apply gain to delayed signal */ |
| tmp = fMultDiv2(tmp, gain); |
| |
| samplesOut[j] = (INT_PCM)FX_DBL2FX_PCM((FIXP_DBL)SATURATE_LEFT_SHIFT( |
| tmp, TDL_GAIN_SCALING + 1, DFRACT_BITS)); |
| } |
| gain >>= 1; |
| } else { |
| /* lookahead delay, apply gain=1.0f */ |
| for (j = 0; j < channels; j++) { |
| tmp = p_delayBuf[j]; |
| p_delayBuf[j] = fMult((FIXP_PCM_LIM)samplesIn[j], additionalGain); |
| samplesOut[j] = (INT_PCM)FX_DBL2FX_PCM((FIXP_DBL)SATURATE_LEFT_SHIFT( |
| tmp, TDL_GAIN_SCALING, DFRACT_BITS)); |
| } |
| } |
| |
| delayBufIdx++; |
| if (delayBufIdx >= attack) { |
| delayBufIdx = 0; |
| } |
| |
| /* save minimum gain factor */ |
| if (gain < minGain) { |
| minGain = gain; |
| } |
| |
| /* advance sample pointer by <channel> samples */ |
| samplesIn += channels; |
| samplesOut += channels; |
| } |
| |
| limiter->max = max; |
| limiter->maxBufIdx = maxBufIdx; |
| limiter->cor = cor; |
| limiter->delayBufIdx = delayBufIdx; |
| |
| limiter->smoothState0 = smoothState0; |
| limiter->additionalGainFilterState = additionalGainSmoothState; |
| limiter->additionalGainFilterState1 = additionalGainSmoothState1; |
| |
| limiter->minGain = minGain; |
| |
| limiter->additionalGainPrev = pGain[0]; |
| |
| return TDLIMIT_OK; |
| } |
| } |
| |
| /* set limiter threshold */ |
| TDLIMITER_ERROR pcmLimiter_SetThreshold(TDLimiterPtr limiter, |
| FIXP_DBL threshold) { |
| if (limiter == NULL) return TDLIMIT_INVALID_HANDLE; |
| |
| limiter->threshold = threshold >> TDL_GAIN_SCALING; |
| |
| return TDLIMIT_OK; |
| } |
| |
| /* reset limiter */ |
| TDLIMITER_ERROR pcmLimiter_Reset(TDLimiterPtr limiter) { |
| if (limiter != NULL) { |
| limiter->maxBufIdx = 0; |
| limiter->delayBufIdx = 0; |
| limiter->max = (FIXP_DBL)0; |
| limiter->cor = FL2FXCONST_DBL(1.0f / (1 << 1)); |
| limiter->smoothState0 = FL2FXCONST_DBL(1.0f / (1 << 1)); |
| limiter->minGain = FL2FXCONST_DBL(1.0f / (1 << 1)); |
| |
| limiter->additionalGainPrev = |
| FL2FXCONST_DBL(1.0f / (1 << TDL_GAIN_SCALING)); |
| limiter->additionalGainFilterState = |
| FL2FXCONST_DBL(1.0f / (1 << TDL_GAIN_SCALING)); |
| limiter->additionalGainFilterState1 = |
| FL2FXCONST_DBL(1.0f / (1 << TDL_GAIN_SCALING)); |
| |
| FDKmemset(limiter->maxBuf, 0, (limiter->attack + 1) * sizeof(FIXP_DBL)); |
| FDKmemset(limiter->delayBuf, 0, |
| limiter->attack * limiter->channels * sizeof(FIXP_DBL)); |
| } else { |
| return TDLIMIT_INVALID_HANDLE; |
| } |
| |
| return TDLIMIT_OK; |
| } |
| |
| /* destroy limiter */ |
| TDLIMITER_ERROR pcmLimiter_Destroy(TDLimiterPtr limiter) { |
| if (limiter != NULL) { |
| FDKfree(limiter->maxBuf); |
| FDKfree(limiter->delayBuf); |
| |
| FDKfree(limiter); |
| } else { |
| return TDLIMIT_INVALID_HANDLE; |
| } |
| return TDLIMIT_OK; |
| } |
| |
| /* get delay in samples */ |
| unsigned int pcmLimiter_GetDelay(TDLimiterPtr limiter) { |
| FDK_ASSERT(limiter != NULL); |
| return limiter->attack; |
| } |
| |
| /* get maximum gain reduction of last processed block */ |
| INT pcmLimiter_GetMaxGainReduction(TDLimiterPtr limiter) { |
| /* maximum gain reduction in dB = -20 * log10(limiter->minGain) |
| = -20 * log2(limiter->minGain)/log2(10) = -6.0206*log2(limiter->minGain) */ |
| int e_ans; |
| FIXP_DBL loggain, maxGainReduction; |
| |
| FDK_ASSERT(limiter != NULL); |
| |
| loggain = fLog2(limiter->minGain, 1, &e_ans); |
| |
| maxGainReduction = fMult(loggain, FL2FXCONST_DBL(-6.0206f / (1 << 3))); |
| |
| return fixp_roundToInt(maxGainReduction, (e_ans + 3)); |
| } |
| |
| /* set number of channels */ |
| TDLIMITER_ERROR pcmLimiter_SetNChannels(TDLimiterPtr limiter, |
| unsigned int nChannels) { |
| if (limiter == NULL) return TDLIMIT_INVALID_HANDLE; |
| |
| if (nChannels > limiter->maxChannels) return TDLIMIT_INVALID_PARAMETER; |
| |
| limiter->channels = nChannels; |
| // pcmLimiter_Reset(limiter); |
| |
| return TDLIMIT_OK; |
| } |
| |
| /* set sampling rate */ |
| TDLIMITER_ERROR pcmLimiter_SetSampleRate(TDLimiterPtr limiter, |
| UINT sampleRate) { |
| unsigned int attack, release; |
| FIXP_DBL attackConst, releaseConst, exponent; |
| INT e_ans; |
| |
| if (limiter == NULL) return TDLIMIT_INVALID_HANDLE; |
| |
| if (sampleRate > limiter->maxSampleRate) return TDLIMIT_INVALID_PARAMETER; |
| |
| /* update attack and release time in samples */ |
| attack = (unsigned int)(limiter->attackMs * sampleRate / 1000); |
| release = (unsigned int)(limiter->releaseMs * sampleRate / 1000); |
| |
| /* attackConst = pow(0.1, 1.0 / (attack + 1)) */ |
| exponent = invFixp(attack + 1); |
| attackConst = fPow(FL2FXCONST_DBL(0.1f), 0, exponent, 0, &e_ans); |
| attackConst = scaleValue(attackConst, e_ans); |
| |
| /* releaseConst = (float)pow(0.1, 1.0 / (release + 1)) */ |
| exponent = invFixp(release + 1); |
| releaseConst = fPow(FL2FXCONST_DBL(0.1f), 0, exponent, 0, &e_ans); |
| releaseConst = scaleValue(releaseConst, e_ans); |
| |
| limiter->attack = attack; |
| limiter->attackConst = attackConst; |
| limiter->releaseConst = releaseConst; |
| limiter->sampleRate = sampleRate; |
| |
| /* reset */ |
| // pcmLimiter_Reset(limiter); |
| |
| return TDLIMIT_OK; |
| } |
| |
| /* set attack time */ |
| TDLIMITER_ERROR pcmLimiter_SetAttack(TDLimiterPtr limiter, |
| unsigned int attackMs) { |
| unsigned int attack; |
| FIXP_DBL attackConst, exponent; |
| INT e_ans; |
| |
| if (limiter == NULL) return TDLIMIT_INVALID_HANDLE; |
| |
| if (attackMs > limiter->maxAttackMs) return TDLIMIT_INVALID_PARAMETER; |
| |
| /* calculate attack time in samples */ |
| attack = (unsigned int)(attackMs * limiter->sampleRate / 1000); |
| |
| /* attackConst = pow(0.1, 1.0 / (attack + 1)) */ |
| exponent = invFixp(attack + 1); |
| attackConst = fPow(FL2FXCONST_DBL(0.1f), 0, exponent, 0, &e_ans); |
| attackConst = scaleValue(attackConst, e_ans); |
| |
| limiter->attack = attack; |
| limiter->attackConst = attackConst; |
| limiter->attackMs = attackMs; |
| |
| return TDLIMIT_OK; |
| } |
| |
| /* set release time */ |
| TDLIMITER_ERROR pcmLimiter_SetRelease(TDLimiterPtr limiter, |
| unsigned int releaseMs) { |
| unsigned int release; |
| FIXP_DBL releaseConst, exponent; |
| INT e_ans; |
| |
| if (limiter == NULL) return TDLIMIT_INVALID_HANDLE; |
| |
| /* calculate release time in samples */ |
| release = (unsigned int)(releaseMs * limiter->sampleRate / 1000); |
| |
| /* releaseConst = (float)pow(0.1, 1.0 / (release + 1)) */ |
| exponent = invFixp(release + 1); |
| releaseConst = fPow(FL2FXCONST_DBL(0.1f), 0, exponent, 0, &e_ans); |
| releaseConst = scaleValue(releaseConst, e_ans); |
| |
| limiter->releaseConst = releaseConst; |
| limiter->releaseMs = releaseMs; |
| |
| return TDLIMIT_OK; |
| } |
| |
| /* Get library info for this module. */ |
| TDLIMITER_ERROR pcmLimiter_GetLibInfo(LIB_INFO* info) { |
| int i; |
| |
| if (info == NULL) { |
| return TDLIMIT_INVALID_PARAMETER; |
| } |
| |
| /* Search for next free tab */ |
| for (i = 0; i < FDK_MODULE_LAST; i++) { |
| if (info[i].module_id == FDK_NONE) break; |
| } |
| if (i == FDK_MODULE_LAST) { |
| return TDLIMIT_UNKNOWN; |
| } |
| |
| /* Add the library info */ |
| info[i].module_id = FDK_TDLIMIT; |
| info[i].version = |
| LIB_VERSION(PCMUTIL_LIB_VL0, PCMUTIL_LIB_VL1, PCMUTIL_LIB_VL2); |
| LIB_VERSION_STRING(info + i); |
| info[i].build_date = PCMUTIL_LIB_BUILD_DATE; |
| info[i].build_time = PCMUTIL_LIB_BUILD_TIME; |
| info[i].title = TDLIMIT_LIB_TITLE; |
| |
| /* Set flags */ |
| info[i].flags = CAPF_LIMITER; |
| |
| /* Add lib info for FDK tools (if not yet done). */ |
| FDK_toolsGetLibInfo(info); |
| |
| return TDLIMIT_OK; |
| } |