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Diffstat (limited to 'fdk-aac/libSBRdec/src/env_dec.cpp')
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diff --git a/fdk-aac/libSBRdec/src/env_dec.cpp b/fdk-aac/libSBRdec/src/env_dec.cpp new file mode 100644 index 0000000..95807c9 --- /dev/null +++ b/fdk-aac/libSBRdec/src/env_dec.cpp @@ -0,0 +1,873 @@ +/* ----------------------------------------------------------------------------- +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 +----------------------------------------------------------------------------- */ + +/**************************** SBR decoder library ****************************** + + Author(s): + + Description: + +*******************************************************************************/ + +/*! + \file + \brief envelope decoding + This module provides envelope decoding and error concealment algorithms. The + main entry point is decodeSbrData(). + + \sa decodeSbrData(),\ref documentationOverview +*/ + +#include "env_dec.h" + +#include "env_extr.h" +#include "transcendent.h" + +#include "genericStds.h" + +static void decodeEnvelope(HANDLE_SBR_HEADER_DATA hHeaderData, + HANDLE_SBR_FRAME_DATA h_sbr_data, + HANDLE_SBR_PREV_FRAME_DATA h_prev_data, + HANDLE_SBR_PREV_FRAME_DATA h_prev_data_otherChannel); +static void sbr_envelope_unmapping(HANDLE_SBR_HEADER_DATA hHeaderData, + HANDLE_SBR_FRAME_DATA h_data_left, + HANDLE_SBR_FRAME_DATA h_data_right); +static void requantizeEnvelopeData(HANDLE_SBR_FRAME_DATA h_sbr_data, + int ampResolution); +static void deltaToLinearPcmEnvelopeDecoding( + HANDLE_SBR_HEADER_DATA hHeaderData, HANDLE_SBR_FRAME_DATA h_sbr_data, + HANDLE_SBR_PREV_FRAME_DATA h_prev_data); +static void decodeNoiseFloorlevels(HANDLE_SBR_HEADER_DATA hHeaderData, + HANDLE_SBR_FRAME_DATA h_sbr_data, + HANDLE_SBR_PREV_FRAME_DATA h_prev_data); +static void timeCompensateFirstEnvelope(HANDLE_SBR_HEADER_DATA hHeaderData, + HANDLE_SBR_FRAME_DATA h_sbr_data, + HANDLE_SBR_PREV_FRAME_DATA h_prev_data); +static int checkEnvelopeData(HANDLE_SBR_HEADER_DATA hHeaderData, + HANDLE_SBR_FRAME_DATA h_sbr_data, + HANDLE_SBR_PREV_FRAME_DATA h_prev_data); + +#define SBR_ENERGY_PAN_OFFSET (12 << ENV_EXP_FRACT) +#define SBR_MAX_ENERGY (35 << ENV_EXP_FRACT) + +#define DECAY (1 << ENV_EXP_FRACT) + +#if ENV_EXP_FRACT +#define DECAY_COUPLING \ + (1 << (ENV_EXP_FRACT - 1)) /*!< corresponds to a value of 0.5 */ +#else +#define DECAY_COUPLING \ + 1 /*!< If the energy data is not shifted, use 1 instead of 0.5 */ +#endif + +/*! + \brief Convert table index +*/ +static int indexLow2High(int offset, /*!< mapping factor */ + int index, /*!< index to scalefactor band */ + int res) /*!< frequency resolution */ +{ + if (res == 0) { + if (offset >= 0) { + if (index < offset) + return (index); + else + return (2 * index - offset); + } else { + offset = -offset; + if (index < offset) + return (2 * index + index); + else + return (2 * index + offset); + } + } else + return (index); +} + +/*! + \brief Update previous envelope value for delta-coding + + The current envelope values needs to be stored for delta-coding + in the next frame. The stored envelope is always represented with + the high frequency resolution. If the current envelope uses the + low frequency resolution, the energy value will be mapped to the + corresponding high-res bands. +*/ +static void mapLowResEnergyVal( + FIXP_SGL currVal, /*!< current energy value */ + FIXP_SGL *prevData, /*!< pointer to previous data vector */ + int offset, /*!< mapping factor */ + int index, /*!< index to scalefactor band */ + int res) /*!< frequeny resolution */ +{ + if (res == 0) { + if (offset >= 0) { + if (index < offset) + prevData[index] = currVal; + else { + prevData[2 * index - offset] = currVal; + prevData[2 * index + 1 - offset] = currVal; + } + } else { + offset = -offset; + if (index < offset) { + prevData[3 * index] = currVal; + prevData[3 * index + 1] = currVal; + prevData[3 * index + 2] = currVal; + } else { + prevData[2 * index + offset] = currVal; + prevData[2 * index + 1 + offset] = currVal; + } + } + } else + prevData[index] = currVal; +} + +/*! + \brief Convert raw envelope and noisefloor data to energy levels + + This function is being called by sbrDecoder_ParseElement() and provides two + important algorithms: + + First the function decodes envelopes and noise floor levels as described in + requantizeEnvelopeData() and sbr_envelope_unmapping(). The function also + implements concealment algorithms in case there are errors within the sbr + data. For both operations fractional arithmetic is used. Therefore you might + encounter different output values on your target system compared to the + reference implementation. +*/ +void decodeSbrData( + HANDLE_SBR_HEADER_DATA hHeaderData, /*!< Static control data */ + HANDLE_SBR_FRAME_DATA + h_data_left, /*!< pointer to left channel frame data */ + HANDLE_SBR_PREV_FRAME_DATA + h_prev_data_left, /*!< pointer to left channel previous frame data */ + HANDLE_SBR_FRAME_DATA + h_data_right, /*!< pointer to right channel frame data */ + HANDLE_SBR_PREV_FRAME_DATA + h_prev_data_right) /*!< pointer to right channel previous frame data */ +{ + FIXP_SGL tempSfbNrgPrev[MAX_FREQ_COEFFS]; + int errLeft; + + /* Save previous energy values to be able to reuse them later for concealment. + */ + FDKmemcpy(tempSfbNrgPrev, h_prev_data_left->sfb_nrg_prev, + MAX_FREQ_COEFFS * sizeof(FIXP_SGL)); + + if (hHeaderData->frameErrorFlag || hHeaderData->bs_info.pvc_mode == 0) { + decodeEnvelope(hHeaderData, h_data_left, h_prev_data_left, + h_prev_data_right); + } else { + FDK_ASSERT(h_data_right == NULL); + } + decodeNoiseFloorlevels(hHeaderData, h_data_left, h_prev_data_left); + + if (h_data_right != NULL) { + errLeft = hHeaderData->frameErrorFlag; + decodeEnvelope(hHeaderData, h_data_right, h_prev_data_right, + h_prev_data_left); + decodeNoiseFloorlevels(hHeaderData, h_data_right, h_prev_data_right); + + if (!errLeft && hHeaderData->frameErrorFlag) { + /* If an error occurs in the right channel where the left channel seemed + ok, we apply concealment also on the left channel. This ensures that + the coupling modes of both channels match and that we have the same + number of envelopes in coupling mode. However, as the left channel has + already been processed before, the resulting energy levels are not the + same as if the left channel had been concealed during the first call of + decodeEnvelope(). + */ + /* Restore previous energy values for concealment, because the values have + been overwritten by the first call of decodeEnvelope(). */ + FDKmemcpy(h_prev_data_left->sfb_nrg_prev, tempSfbNrgPrev, + MAX_FREQ_COEFFS * sizeof(FIXP_SGL)); + /* Do concealment */ + decodeEnvelope(hHeaderData, h_data_left, h_prev_data_left, + h_prev_data_right); + } + + if (h_data_left->coupling) { + sbr_envelope_unmapping(hHeaderData, h_data_left, h_data_right); + } + } + + /* Display the data for debugging: */ +} + +/*! + \brief Convert from coupled channels to independent L/R data +*/ +static void sbr_envelope_unmapping( + HANDLE_SBR_HEADER_DATA hHeaderData, /*!< Static control data */ + HANDLE_SBR_FRAME_DATA h_data_left, /*!< pointer to left channel */ + HANDLE_SBR_FRAME_DATA h_data_right) /*!< pointer to right channel */ +{ + int i; + FIXP_SGL tempL_m, tempR_m, tempRplus1_m, newL_m, newR_m; + SCHAR tempL_e, tempR_e, tempRplus1_e, newL_e, newR_e; + + /* 1. Unmap (already dequantized) coupled envelope energies */ + + for (i = 0; i < h_data_left->nScaleFactors; i++) { + tempR_m = (FIXP_SGL)((LONG)h_data_right->iEnvelope[i] & MASK_M); + tempR_e = (SCHAR)((LONG)h_data_right->iEnvelope[i] & MASK_E); + + tempR_e -= (18 + NRG_EXP_OFFSET); /* -18 = ld(UNMAPPING_SCALE / + h_data_right->nChannels) */ + tempL_m = (FIXP_SGL)((LONG)h_data_left->iEnvelope[i] & MASK_M); + tempL_e = (SCHAR)((LONG)h_data_left->iEnvelope[i] & MASK_E); + + tempL_e -= NRG_EXP_OFFSET; + + /* Calculate tempRight+1 */ + FDK_add_MantExp(tempR_m, tempR_e, FL2FXCONST_SGL(0.5f), 1, /* 1.0 */ + &tempRplus1_m, &tempRplus1_e); + + FDK_divide_MantExp(tempL_m, tempL_e + 1, /* 2 * tempLeft */ + tempRplus1_m, tempRplus1_e, &newR_m, &newR_e); + + if (newR_m >= ((FIXP_SGL)MAXVAL_SGL - ROUNDING)) { + newR_m >>= 1; + newR_e += 1; + } + + newL_m = FX_DBL2FX_SGL(fMult(tempR_m, newR_m)); + newL_e = tempR_e + newR_e; + + h_data_right->iEnvelope[i] = + ((FIXP_SGL)((SHORT)(FIXP_SGL)(newR_m + ROUNDING) & MASK_M)) + + (FIXP_SGL)((SHORT)(FIXP_SGL)(newR_e + NRG_EXP_OFFSET) & MASK_E); + h_data_left->iEnvelope[i] = + ((FIXP_SGL)((SHORT)(FIXP_SGL)(newL_m + ROUNDING) & MASK_M)) + + (FIXP_SGL)((SHORT)(FIXP_SGL)(newL_e + NRG_EXP_OFFSET) & MASK_E); + } + + /* 2. Dequantize and unmap coupled noise floor levels */ + + for (i = 0; i < hHeaderData->freqBandData.nNfb * + h_data_left->frameInfo.nNoiseEnvelopes; + i++) { + tempL_e = (SCHAR)(6 - (LONG)h_data_left->sbrNoiseFloorLevel[i]); + tempR_e = (SCHAR)((LONG)h_data_right->sbrNoiseFloorLevel[i] - + 12) /*SBR_ENERGY_PAN_OFFSET*/; + + /* Calculate tempR+1 */ + FDK_add_MantExp(FL2FXCONST_SGL(0.5f), 1 + tempR_e, /* tempR */ + FL2FXCONST_SGL(0.5f), 1, /* 1.0 */ + &tempRplus1_m, &tempRplus1_e); + + /* Calculate 2*tempLeft/(tempR+1) */ + FDK_divide_MantExp(FL2FXCONST_SGL(0.5f), tempL_e + 2, /* 2 * tempLeft */ + tempRplus1_m, tempRplus1_e, &newR_m, &newR_e); + + /* if (newR_m >= ((FIXP_SGL)MAXVAL_SGL - ROUNDING)) { + newR_m >>= 1; + newR_e += 1; + } */ + + /* L = tempR * R */ + newL_m = newR_m; + newL_e = newR_e + tempR_e; + h_data_right->sbrNoiseFloorLevel[i] = + ((FIXP_SGL)((SHORT)(FIXP_SGL)(newR_m + ROUNDING) & MASK_M)) + + (FIXP_SGL)((SHORT)(FIXP_SGL)(newR_e + NOISE_EXP_OFFSET) & MASK_E); + h_data_left->sbrNoiseFloorLevel[i] = + ((FIXP_SGL)((SHORT)(FIXP_SGL)(newL_m + ROUNDING) & MASK_M)) + + (FIXP_SGL)((SHORT)(FIXP_SGL)(newL_e + NOISE_EXP_OFFSET) & MASK_E); + } +} + +/*! + \brief Simple alternative to the real SBR concealment + + If the real frameInfo is not available due to a frame loss, a replacement will + be constructed with 1 envelope spanning the whole frame (FIX-FIX). + The delta-coded energies are set to negative values, resulting in a fade-down. + In case of coupling, the balance-channel will move towards the center. +*/ +static void leanSbrConcealment( + HANDLE_SBR_HEADER_DATA hHeaderData, /*!< Static control data */ + HANDLE_SBR_FRAME_DATA h_sbr_data, /*!< pointer to current data */ + HANDLE_SBR_PREV_FRAME_DATA h_prev_data /*!< pointer to data of last frame */ +) { + FIXP_SGL target; /* targeted level for sfb_nrg_prev during fade-down */ + FIXP_SGL step; /* speed of fade */ + int i; + + int currentStartPos = + fMax(0, h_prev_data->stopPos - hHeaderData->numberTimeSlots); + int currentStopPos = hHeaderData->numberTimeSlots; + + /* Use some settings of the previous frame */ + h_sbr_data->ampResolutionCurrentFrame = h_prev_data->ampRes; + h_sbr_data->coupling = h_prev_data->coupling; + for (i = 0; i < MAX_INVF_BANDS; i++) + h_sbr_data->sbr_invf_mode[i] = h_prev_data->sbr_invf_mode[i]; + + /* Generate concealing control data */ + + h_sbr_data->frameInfo.nEnvelopes = 1; + h_sbr_data->frameInfo.borders[0] = currentStartPos; + h_sbr_data->frameInfo.borders[1] = currentStopPos; + h_sbr_data->frameInfo.freqRes[0] = 1; + h_sbr_data->frameInfo.tranEnv = -1; /* no transient */ + h_sbr_data->frameInfo.nNoiseEnvelopes = 1; + h_sbr_data->frameInfo.bordersNoise[0] = currentStartPos; + h_sbr_data->frameInfo.bordersNoise[1] = currentStopPos; + + h_sbr_data->nScaleFactors = hHeaderData->freqBandData.nSfb[1]; + + /* Generate fake envelope data */ + + h_sbr_data->domain_vec[0] = 1; + + if (h_sbr_data->coupling == COUPLING_BAL) { + target = (FIXP_SGL)SBR_ENERGY_PAN_OFFSET; + step = (FIXP_SGL)DECAY_COUPLING; + } else { + target = FL2FXCONST_SGL(0.0f); + step = (FIXP_SGL)DECAY; + } + if (hHeaderData->bs_info.ampResolution == 0) { + target <<= 1; + step <<= 1; + } + + for (i = 0; i < h_sbr_data->nScaleFactors; i++) { + if (h_prev_data->sfb_nrg_prev[i] > target) + h_sbr_data->iEnvelope[i] = -step; + else + h_sbr_data->iEnvelope[i] = step; + } + + /* Noisefloor levels are always cleared ... */ + + h_sbr_data->domain_vec_noise[0] = 1; + FDKmemclear(h_sbr_data->sbrNoiseFloorLevel, + sizeof(h_sbr_data->sbrNoiseFloorLevel)); + + /* ... and so are the sines */ + FDKmemclear(h_sbr_data->addHarmonics, + sizeof(ULONG) * ADD_HARMONICS_FLAGS_SIZE); +} + +/*! + \brief Build reference energies and noise levels from bitstream elements +*/ +static void decodeEnvelope( + HANDLE_SBR_HEADER_DATA hHeaderData, /*!< Static control data */ + HANDLE_SBR_FRAME_DATA h_sbr_data, /*!< pointer to current data */ + HANDLE_SBR_PREV_FRAME_DATA + h_prev_data, /*!< pointer to data of last frame */ + HANDLE_SBR_PREV_FRAME_DATA + otherChannel /*!< other channel's last frame data */ +) { + int i; + int fFrameError = hHeaderData->frameErrorFlag; + FIXP_SGL tempSfbNrgPrev[MAX_FREQ_COEFFS]; + + if (!fFrameError) { + /* + To avoid distortions after bad frames, set the error flag if delta coding + in time occurs. However, SBR can take a little longer to come up again. + */ + if (h_prev_data->frameErrorFlag) { + if (h_sbr_data->domain_vec[0] != 0) { + fFrameError = 1; + } + } else { + /* Check that the previous stop position and the current start position + match. (Could be done in checkFrameInfo(), but the previous frame data + is not available there) */ + if (h_sbr_data->frameInfo.borders[0] != + h_prev_data->stopPos - hHeaderData->numberTimeSlots) { + /* Both the previous as well as the current frame are flagged to be ok, + * but they do not match! */ + if (h_sbr_data->domain_vec[0] == 1) { + /* Prefer concealment over delta-time coding between the mismatching + * frames */ + fFrameError = 1; + } else { + /* Close the gap in time by triggering timeCompensateFirstEnvelope() + */ + fFrameError = 1; + } + } + } + } + + if (fFrameError) /* Error is detected */ + { + leanSbrConcealment(hHeaderData, h_sbr_data, h_prev_data); + + /* decode the envelope data to linear PCM */ + deltaToLinearPcmEnvelopeDecoding(hHeaderData, h_sbr_data, h_prev_data); + } else /*Do a temporary dummy decoding and check that the envelope values are + within limits */ + { + if (h_prev_data->frameErrorFlag) { + timeCompensateFirstEnvelope(hHeaderData, h_sbr_data, h_prev_data); + if (h_sbr_data->coupling != h_prev_data->coupling) { + /* + Coupling mode has changed during concealment. + The stored energy levels need to be converted. + */ + for (i = 0; i < hHeaderData->freqBandData.nSfb[1]; i++) { + /* Former Level-Channel will be used for both channels */ + if (h_prev_data->coupling == COUPLING_BAL) { + h_prev_data->sfb_nrg_prev[i] = + (otherChannel != NULL) ? otherChannel->sfb_nrg_prev[i] + : (FIXP_SGL)SBR_ENERGY_PAN_OFFSET; + } + /* Former L/R will be combined as the new Level-Channel */ + else if (h_sbr_data->coupling == COUPLING_LEVEL && + otherChannel != NULL) { + h_prev_data->sfb_nrg_prev[i] = (h_prev_data->sfb_nrg_prev[i] + + otherChannel->sfb_nrg_prev[i]) >> + 1; + } else if (h_sbr_data->coupling == COUPLING_BAL) { + h_prev_data->sfb_nrg_prev[i] = (FIXP_SGL)SBR_ENERGY_PAN_OFFSET; + } + } + } + } + FDKmemcpy(tempSfbNrgPrev, h_prev_data->sfb_nrg_prev, + MAX_FREQ_COEFFS * sizeof(FIXP_SGL)); + + deltaToLinearPcmEnvelopeDecoding(hHeaderData, h_sbr_data, h_prev_data); + + fFrameError = checkEnvelopeData(hHeaderData, h_sbr_data, h_prev_data); + + if (fFrameError) { + hHeaderData->frameErrorFlag = 1; + FDKmemcpy(h_prev_data->sfb_nrg_prev, tempSfbNrgPrev, + MAX_FREQ_COEFFS * sizeof(FIXP_SGL)); + decodeEnvelope(hHeaderData, h_sbr_data, h_prev_data, otherChannel); + return; + } + } + + requantizeEnvelopeData(h_sbr_data, h_sbr_data->ampResolutionCurrentFrame); + + hHeaderData->frameErrorFlag = fFrameError; +} + +/*! + \brief Verify that envelope energies are within the allowed range + \return 0 if all is fine, 1 if an envelope value was too high +*/ +static int checkEnvelopeData( + HANDLE_SBR_HEADER_DATA hHeaderData, /*!< Static control data */ + HANDLE_SBR_FRAME_DATA h_sbr_data, /*!< pointer to current data */ + HANDLE_SBR_PREV_FRAME_DATA h_prev_data /*!< pointer to data of last frame */ +) { + FIXP_SGL *iEnvelope = h_sbr_data->iEnvelope; + FIXP_SGL *sfb_nrg_prev = h_prev_data->sfb_nrg_prev; + int i = 0, errorFlag = 0; + FIXP_SGL sbr_max_energy = (h_sbr_data->ampResolutionCurrentFrame == 1) + ? SBR_MAX_ENERGY + : (SBR_MAX_ENERGY << 1); + + /* + Range check for current energies + */ + for (i = 0; i < h_sbr_data->nScaleFactors; i++) { + if (iEnvelope[i] > sbr_max_energy) { + errorFlag = 1; + } + if (iEnvelope[i] < FL2FXCONST_SGL(0.0f)) { + errorFlag = 1; + /* iEnvelope[i] = FL2FXCONST_SGL(0.0f); */ + } + } + + /* + Range check for previous energies + */ + for (i = 0; i < hHeaderData->freqBandData.nSfb[1]; i++) { + sfb_nrg_prev[i] = fixMax(sfb_nrg_prev[i], FL2FXCONST_SGL(0.0f)); + sfb_nrg_prev[i] = fixMin(sfb_nrg_prev[i], sbr_max_energy); + } + + return (errorFlag); +} + +/*! + \brief Verify that the noise levels are within the allowed range + + The function is equivalent to checkEnvelopeData(). + When the noise-levels are being decoded, it is already too late for + concealment. Therefore the noise levels are simply limited here. +*/ +static void limitNoiseLevels( + HANDLE_SBR_HEADER_DATA hHeaderData, /*!< Static control data */ + HANDLE_SBR_FRAME_DATA h_sbr_data) /*!< pointer to current data */ +{ + int i; + int nNfb = hHeaderData->freqBandData.nNfb; + +/* + Set range limits. The exact values depend on the coupling mode. + However this limitation is primarily intended to avoid unlimited + accumulation of the delta-coded noise levels. +*/ +#define lowerLimit \ + ((FIXP_SGL)0) /* lowerLimit actually refers to the _highest_ noise energy */ +#define upperLimit \ + ((FIXP_SGL)35) /* upperLimit actually refers to the _lowest_ noise energy */ + + /* + Range check for current noise levels + */ + for (i = 0; i < h_sbr_data->frameInfo.nNoiseEnvelopes * nNfb; i++) { + h_sbr_data->sbrNoiseFloorLevel[i] = + fixMin(h_sbr_data->sbrNoiseFloorLevel[i], upperLimit); + h_sbr_data->sbrNoiseFloorLevel[i] = + fixMax(h_sbr_data->sbrNoiseFloorLevel[i], lowerLimit); + } +} + +/*! + \brief Compensate for the wrong timing that might occur after a frame error. +*/ +static void timeCompensateFirstEnvelope( + HANDLE_SBR_HEADER_DATA hHeaderData, /*!< Static control data */ + HANDLE_SBR_FRAME_DATA h_sbr_data, /*!< pointer to actual data */ + HANDLE_SBR_PREV_FRAME_DATA + h_prev_data) /*!< pointer to data of last frame */ +{ + int i, nScalefactors; + FRAME_INFO *pFrameInfo = &h_sbr_data->frameInfo; + UCHAR *nSfb = hHeaderData->freqBandData.nSfb; + int estimatedStartPos = + fMax(0, h_prev_data->stopPos - hHeaderData->numberTimeSlots); + int refLen, newLen, shift; + FIXP_SGL deltaExp; + + /* Original length of first envelope according to bitstream */ + refLen = pFrameInfo->borders[1] - pFrameInfo->borders[0]; + /* Corrected length of first envelope (concealing can make the first envelope + * longer) */ + newLen = pFrameInfo->borders[1] - estimatedStartPos; + + if (newLen <= 0) { + /* An envelope length of <= 0 would not work, so we don't use it. + May occur if the previous frame was flagged bad due to a mismatch + of the old and new frame infos. */ + newLen = refLen; + estimatedStartPos = pFrameInfo->borders[0]; + } + + deltaExp = FDK_getNumOctavesDiv8(newLen, refLen); + + /* Shift by -3 to rescale ld-table, ampRes-1 to enable coarser steps */ + shift = (FRACT_BITS - 1 - ENV_EXP_FRACT - 1 + + h_sbr_data->ampResolutionCurrentFrame - 3); + deltaExp = deltaExp >> shift; + pFrameInfo->borders[0] = estimatedStartPos; + pFrameInfo->bordersNoise[0] = estimatedStartPos; + + if (h_sbr_data->coupling != COUPLING_BAL) { + nScalefactors = (pFrameInfo->freqRes[0]) ? nSfb[1] : nSfb[0]; + + for (i = 0; i < nScalefactors; i++) + h_sbr_data->iEnvelope[i] = h_sbr_data->iEnvelope[i] + deltaExp; + } +} + +/*! + \brief Convert each envelope value from logarithmic to linear domain + + Energy levels are transmitted in powers of 2, i.e. only the exponent + is extracted from the bitstream. + Therefore, normally only integer exponents can occur. However during + fading (in case of a corrupt bitstream), a fractional part can also + occur. The data in the array iEnvelope is shifted left by ENV_EXP_FRACT + compared to an integer representation so that numbers smaller than 1 + can be represented. + + This function calculates a mantissa corresponding to the fractional + part of the exponent for each reference energy. The array iEnvelope + is converted in place to save memory. Input and output data must + be interpreted differently, as shown in the below figure: + + \image html EnvelopeData.png + + The data is then used in calculateSbrEnvelope(). +*/ +static void requantizeEnvelopeData(HANDLE_SBR_FRAME_DATA h_sbr_data, + int ampResolution) { + int i; + FIXP_SGL mantissa; + int ampShift = 1 - ampResolution; + int exponent; + + /* In case that ENV_EXP_FRACT is changed to something else but 0 or 8, + the initialization of this array has to be adapted! + */ +#if ENV_EXP_FRACT + static const FIXP_SGL pow2[ENV_EXP_FRACT] = { + FL2FXCONST_SGL(0.5f * pow(2.0f, pow(0.5f, 1))), /* 0.7071 */ + FL2FXCONST_SGL(0.5f * pow(2.0f, pow(0.5f, 2))), /* 0.5946 */ + FL2FXCONST_SGL(0.5f * pow(2.0f, pow(0.5f, 3))), + FL2FXCONST_SGL(0.5f * pow(2.0f, pow(0.5f, 4))), + FL2FXCONST_SGL(0.5f * pow(2.0f, pow(0.5f, 5))), + FL2FXCONST_SGL(0.5f * pow(2.0f, pow(0.5f, 6))), + FL2FXCONST_SGL(0.5f * pow(2.0f, pow(0.5f, 7))), + FL2FXCONST_SGL(0.5f * pow(2.0f, pow(0.5f, 8))) /* 0.5013 */ + }; + + int bit, mask; +#endif + + for (i = 0; i < h_sbr_data->nScaleFactors; i++) { + exponent = (LONG)h_sbr_data->iEnvelope[i]; + +#if ENV_EXP_FRACT + + exponent = exponent >> ampShift; + mantissa = 0.5f; + + /* Amplify mantissa according to the fractional part of the + exponent (result will be between 0.500000 and 0.999999) + */ + mask = 1; /* begin with lowest bit of exponent */ + + for (bit = ENV_EXP_FRACT - 1; bit >= 0; bit--) { + if (exponent & mask) { + /* The current bit of the exponent is set, + multiply mantissa with the corresponding factor: */ + mantissa = (FIXP_SGL)((mantissa * pow2[bit]) << 1); + } + /* Advance to next bit */ + mask = mask << 1; + } + + /* Make integer part of exponent right aligned */ + exponent = exponent >> ENV_EXP_FRACT; + +#else + /* In case of the high amplitude resolution, 1 bit of the exponent gets lost + by the shift. This will be compensated by a mantissa of 0.5*sqrt(2) + instead of 0.5 if that bit is 1. */ + mantissa = (exponent & ampShift) ? FL2FXCONST_SGL(0.707106781186548f) + : FL2FXCONST_SGL(0.5f); + exponent = exponent >> ampShift; +#endif + + /* + Mantissa was set to 0.5 (instead of 1.0, therefore increase exponent by + 1). Multiply by L=nChannels=64 by increasing exponent by another 6. + => Increase exponent by 7 + */ + exponent += 7 + NRG_EXP_OFFSET; + + /* Combine mantissa and exponent and write back the result */ + h_sbr_data->iEnvelope[i] = + ((FIXP_SGL)((SHORT)(FIXP_SGL)mantissa & MASK_M)) + + (FIXP_SGL)((SHORT)(FIXP_SGL)exponent & MASK_E); + } +} + +/*! + \brief Build new reference energies from old ones and delta coded data +*/ +static void deltaToLinearPcmEnvelopeDecoding( + HANDLE_SBR_HEADER_DATA hHeaderData, /*!< Static control data */ + HANDLE_SBR_FRAME_DATA h_sbr_data, /*!< pointer to current data */ + HANDLE_SBR_PREV_FRAME_DATA h_prev_data) /*!< pointer to previous data */ +{ + int i, domain, no_of_bands, band, freqRes; + + FIXP_SGL *sfb_nrg_prev = h_prev_data->sfb_nrg_prev; + FIXP_SGL *ptr_nrg = h_sbr_data->iEnvelope; + + int offset = + 2 * hHeaderData->freqBandData.nSfb[0] - hHeaderData->freqBandData.nSfb[1]; + + for (i = 0; i < h_sbr_data->frameInfo.nEnvelopes; i++) { + domain = h_sbr_data->domain_vec[i]; + freqRes = h_sbr_data->frameInfo.freqRes[i]; + + FDK_ASSERT(freqRes >= 0 && freqRes <= 1); + + no_of_bands = hHeaderData->freqBandData.nSfb[freqRes]; + + FDK_ASSERT(no_of_bands < (64)); + + if (domain == 0) { + mapLowResEnergyVal(*ptr_nrg, sfb_nrg_prev, offset, 0, freqRes); + ptr_nrg++; + for (band = 1; band < no_of_bands; band++) { + *ptr_nrg = *ptr_nrg + *(ptr_nrg - 1); + mapLowResEnergyVal(*ptr_nrg, sfb_nrg_prev, offset, band, freqRes); + ptr_nrg++; + } + } else { + for (band = 0; band < no_of_bands; band++) { + *ptr_nrg = + *ptr_nrg + sfb_nrg_prev[indexLow2High(offset, band, freqRes)]; + mapLowResEnergyVal(*ptr_nrg, sfb_nrg_prev, offset, band, freqRes); + ptr_nrg++; + } + } + } +} + +/*! + \brief Build new noise levels from old ones and delta coded data +*/ +static void decodeNoiseFloorlevels( + HANDLE_SBR_HEADER_DATA hHeaderData, /*!< Static control data */ + HANDLE_SBR_FRAME_DATA h_sbr_data, /*!< pointer to current data */ + HANDLE_SBR_PREV_FRAME_DATA h_prev_data) /*!< pointer to previous data */ +{ + int i; + int nNfb = hHeaderData->freqBandData.nNfb; + int nNoiseFloorEnvelopes = h_sbr_data->frameInfo.nNoiseEnvelopes; + + /* Decode first noise envelope */ + + if (h_sbr_data->domain_vec_noise[0] == 0) { + FIXP_SGL noiseLevel = h_sbr_data->sbrNoiseFloorLevel[0]; + for (i = 1; i < nNfb; i++) { + noiseLevel += h_sbr_data->sbrNoiseFloorLevel[i]; + h_sbr_data->sbrNoiseFloorLevel[i] = noiseLevel; + } + } else { + for (i = 0; i < nNfb; i++) { + h_sbr_data->sbrNoiseFloorLevel[i] += h_prev_data->prevNoiseLevel[i]; + } + } + + /* If present, decode the second noise envelope + Note: nNoiseFloorEnvelopes can only be 1 or 2 */ + + if (nNoiseFloorEnvelopes > 1) { + if (h_sbr_data->domain_vec_noise[1] == 0) { + FIXP_SGL noiseLevel = h_sbr_data->sbrNoiseFloorLevel[nNfb]; + for (i = nNfb + 1; i < 2 * nNfb; i++) { + noiseLevel += h_sbr_data->sbrNoiseFloorLevel[i]; + h_sbr_data->sbrNoiseFloorLevel[i] = noiseLevel; + } + } else { + for (i = 0; i < nNfb; i++) { + h_sbr_data->sbrNoiseFloorLevel[i + nNfb] += + h_sbr_data->sbrNoiseFloorLevel[i]; + } + } + } + + limitNoiseLevels(hHeaderData, h_sbr_data); + + /* Update prevNoiseLevel with the last noise envelope */ + for (i = 0; i < nNfb; i++) + h_prev_data->prevNoiseLevel[i] = + h_sbr_data->sbrNoiseFloorLevel[i + nNfb * (nNoiseFloorEnvelopes - 1)]; + + /* Requantize the noise floor levels in COUPLING_OFF-mode */ + if (!h_sbr_data->coupling) { + int nf_e; + + for (i = 0; i < nNoiseFloorEnvelopes * nNfb; i++) { + nf_e = 6 - (LONG)h_sbr_data->sbrNoiseFloorLevel[i] + 1 + NOISE_EXP_OFFSET; + /* +1 to compensate for a mantissa of 0.5 instead of 1.0 */ + + h_sbr_data->sbrNoiseFloorLevel[i] = + (FIXP_SGL)(((LONG)FL2FXCONST_SGL(0.5f)) + /* mantissa */ + (nf_e & MASK_E)); /* exponent */ + } + } +} |