fuchsia / third_party / android / platform / external / aac / ca5723b92244e44a343febda95dbac59805c16bb / . / libAACdec / src / ldfiltbank.cpp

/* ----------------------------------------------------------------------------- | |

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 | |

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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 | |

----------------------------------------------------------------------------- */ | |

/**************************** AAC decoder library ****************************** | |

Author(s): | |

Description: low delay filterbank | |

*******************************************************************************/ | |

#include "ldfiltbank.h" | |

#include "aac_rom.h" | |

#include "dct.h" | |

#include "FDK_tools_rom.h" | |

#include "mdct.h" | |

#define LDFB_HEADROOM 2 | |

#if defined(__arm__) | |

#endif | |

static void multE2_DinvF_fdk(FIXP_PCM *output, FIXP_DBL *x, const FIXP_WTB *fb, | |

FIXP_DBL *z, const int N) { | |

int i; | |

/* scale for FIXP_DBL -> INT_PCM conversion. */ | |

const int scale = (DFRACT_BITS - SAMPLE_BITS) - LDFB_HEADROOM; | |

#if ((DFRACT_BITS - SAMPLE_BITS - LDFB_HEADROOM) > 0) | |

FIXP_DBL rnd_val_wts0 = (FIXP_DBL)0; | |

FIXP_DBL rnd_val_wts1 = (FIXP_DBL)0; | |

if (-WTS0 - 1 + scale) | |

rnd_val_wts0 = (FIXP_DBL)(1 << (-WTS0 - 1 + scale - 1)); | |

if (-WTS1 - 1 + scale) | |

rnd_val_wts1 = (FIXP_DBL)(1 << (-WTS1 - 1 + scale - 1)); | |

#endif | |

for (i = 0; i < N / 4; i++) { | |

FIXP_DBL z0, z2, tmp; | |

z2 = x[N / 2 + i]; | |

z0 = z2 + (fMultDiv2(z[N / 2 + i], fb[2 * N + i]) >> (-WTS2 - 1)); | |

z[N / 2 + i] = x[N / 2 - 1 - i] + | |

(fMultDiv2(z[N + i], fb[2 * N + N / 2 + i]) >> (-WTS2 - 1)); | |

tmp = (fMultDiv2(z[N / 2 + i], fb[N + N / 2 - 1 - i]) + | |

fMultDiv2(z[i], fb[N + N / 2 + i])); | |

#if ((DFRACT_BITS - SAMPLE_BITS - LDFB_HEADROOM) > 0) | |

FDK_ASSERT((-WTS1 - 1 + scale) >= 0); | |

FDK_ASSERT(tmp <= ((FIXP_DBL)0x7FFFFFFF - | |

rnd_val_wts1)); /* rounding must not cause overflow */ | |

output[(N * 3 / 4 - 1 - i)] = (FIXP_PCM)SATURATE_RIGHT_SHIFT( | |

tmp + rnd_val_wts1, -WTS1 - 1 + scale, PCM_OUT_BITS); | |

#else | |

FDK_ASSERT((WTS1 + 1 - scale) >= 0); | |

output[(N * 3 / 4 - 1 - i)] = | |

(FIXP_PCM)SATURATE_LEFT_SHIFT(tmp, WTS1 + 1 - scale, PCM_OUT_BITS); | |

#endif | |

z[i] = z0; | |

z[N + i] = z2; | |

} | |

for (i = N / 4; i < N / 2; i++) { | |

FIXP_DBL z0, z2, tmp0, tmp1; | |

z2 = x[N / 2 + i]; | |

z0 = z2 + (fMultDiv2(z[N / 2 + i], fb[2 * N + i]) >> (-WTS2 - 1)); | |

z[N / 2 + i] = x[N / 2 - 1 - i] + | |

(fMultDiv2(z[N + i], fb[2 * N + N / 2 + i]) >> (-WTS2 - 1)); | |

tmp0 = (fMultDiv2(z[N / 2 + i], fb[N / 2 - 1 - i]) + | |

fMultDiv2(z[i], fb[N / 2 + i])); | |

tmp1 = (fMultDiv2(z[N / 2 + i], fb[N + N / 2 - 1 - i]) + | |

fMultDiv2(z[i], fb[N + N / 2 + i])); | |

#if ((DFRACT_BITS - SAMPLE_BITS - LDFB_HEADROOM) > 0) | |

FDK_ASSERT((-WTS0 - 1 + scale) >= 0); | |

FDK_ASSERT(tmp0 <= ((FIXP_DBL)0x7FFFFFFF - | |

rnd_val_wts0)); /* rounding must not cause overflow */ | |

FDK_ASSERT(tmp1 <= ((FIXP_DBL)0x7FFFFFFF - | |

rnd_val_wts1)); /* rounding must not cause overflow */ | |

output[(i - N / 4)] = (FIXP_PCM)SATURATE_RIGHT_SHIFT( | |

tmp0 + rnd_val_wts0, -WTS0 - 1 + scale, PCM_OUT_BITS); | |

output[(N * 3 / 4 - 1 - i)] = (FIXP_PCM)SATURATE_RIGHT_SHIFT( | |

tmp1 + rnd_val_wts1, -WTS1 - 1 + scale, PCM_OUT_BITS); | |

#else | |

FDK_ASSERT((WTS0 + 1 - scale) >= 0); | |

output[(i - N / 4)] = | |

(FIXP_PCM)SATURATE_LEFT_SHIFT(tmp0, WTS0 + 1 - scale, PCM_OUT_BITS); | |

output[(N * 3 / 4 - 1 - i)] = | |

(FIXP_PCM)SATURATE_LEFT_SHIFT(tmp1, WTS1 + 1 - scale, PCM_OUT_BITS); | |

#endif | |

z[i] = z0; | |

z[N + i] = z2; | |

} | |

/* Exchange quarter parts of x to bring them in the "right" order */ | |

for (i = 0; i < N / 4; i++) { | |

FIXP_DBL tmp0 = fMultDiv2(z[i], fb[N / 2 + i]); | |

#if ((DFRACT_BITS - SAMPLE_BITS - LDFB_HEADROOM) > 0) | |

FDK_ASSERT((-WTS0 - 1 + scale) >= 0); | |

FDK_ASSERT(tmp0 <= ((FIXP_DBL)0x7FFFFFFF - | |

rnd_val_wts0)); /* rounding must not cause overflow */ | |

output[(N * 3 / 4 + i)] = (FIXP_PCM)SATURATE_RIGHT_SHIFT( | |

tmp0 + rnd_val_wts0, -WTS0 - 1 + scale, PCM_OUT_BITS); | |

#else | |

FDK_ASSERT((WTS0 + 1 - scale) >= 0); | |

output[(N * 3 / 4 + i)] = | |

(FIXP_PCM)SATURATE_LEFT_SHIFT(tmp0, WTS0 + 1 - scale, PCM_OUT_BITS); | |

#endif | |

} | |

} | |

int InvMdctTransformLowDelay_fdk(FIXP_DBL *mdctData, const int mdctData_e, | |

FIXP_PCM *output, FIXP_DBL *fs_buffer, | |

const int N) { | |

const FIXP_WTB *coef; | |

FIXP_DBL gain = (FIXP_DBL)0; | |

int scale = mdctData_e + MDCT_OUT_HEADROOM - | |

LDFB_HEADROOM; /* The LDFB_HEADROOM is compensated inside | |

multE2_DinvF_fdk() below */ | |

int i; | |

/* Select LD window slope */ | |

switch (N) { | |

case 256: | |

coef = LowDelaySynthesis256; | |

break; | |

case 240: | |

coef = LowDelaySynthesis240; | |

break; | |

case 160: | |

coef = LowDelaySynthesis160; | |

break; | |

case 128: | |

coef = LowDelaySynthesis128; | |

break; | |

case 120: | |

coef = LowDelaySynthesis120; | |

break; | |

case 512: | |

coef = LowDelaySynthesis512; | |

break; | |

case 480: | |

default: | |

coef = LowDelaySynthesis480; | |

break; | |

} | |

/* | |

Apply exponent and 1/N factor. | |

Note: "scale" is off by one because for LD_MDCT the window length is twice | |

the window length of a regular MDCT. This is corrected inside | |

multE2_DinvF_fdk(). Refer to ISO/IEC 14496-3:2009 page 277, | |

chapter 4.6.20.2 "Low Delay Window". | |

*/ | |

imdct_gain(&gain, &scale, N); | |

dct_IV(mdctData, N, &scale); | |

if (N == 256 || N == 240 || N == 160) { | |

scale -= 1; | |

} else if (N == 128 || N == 120) { | |

scale -= 2; | |

} | |

if (gain != (FIXP_DBL)0) { | |

for (i = 0; i < N; i++) { | |

mdctData[i] = fMult(mdctData[i], gain); | |

} | |

} | |

scaleValuesSaturate(mdctData, N, scale); | |

/* Since all exponent and factors have been applied, current exponent is zero. | |

*/ | |

multE2_DinvF_fdk(output, mdctData, coef, fs_buffer, N); | |

return (1); | |

} |