From 9bf37cc9712506b2483650c82d3c41152337ef7e Mon Sep 17 00:00:00 2001 From: Dave Burke Date: Tue, 17 Apr 2012 09:51:45 -0700 Subject: Fraunhofer AAC codec. License boilerplate update to follow. Change-Id: I2810460c11a58b6d148d84673cc031f3685e79b5 --- libAACdec/src/ldfiltbank.cpp | 148 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 148 insertions(+) create mode 100644 libAACdec/src/ldfiltbank.cpp (limited to 'libAACdec/src/ldfiltbank.cpp') diff --git a/libAACdec/src/ldfiltbank.cpp b/libAACdec/src/ldfiltbank.cpp new file mode 100644 index 0000000..7a59926 --- /dev/null +++ b/libAACdec/src/ldfiltbank.cpp @@ -0,0 +1,148 @@ +/***************************************************************************\ + * + * (C) copyright Fraunhofer - IIS (2006) + All Rights Reserved + + Please be advised that this software and/or program delivery is + Confidential Information of Fraunhofer and subject to and covered by the + + Fraunhofer IIS Software Evaluation Agreement + between Google Inc. and Fraunhofer + effective and in full force since March 1, 2012. + + You may use this software and/or program only under the terms and + conditions described in the above mentioned Fraunhofer IIS Software + Evaluation Agreement. Any other and/or further use requires a separate agreement. + +* + * filename: ldfiltbank.c + * project : MPEG-4 Audio Decoder + * contents/description: low delay filterbank + * + * This software and/or program is protected by copyright law and + * international treaties. Any reproduction or distribution of this + * software and/or program, or any portion of it, may result in severe + * civil and criminal penalties, and will be prosecuted to the maximum + * extent possible under law. + * + * $Id$ + * +\***************************************************************************/ + +#include "ldfiltbank.h" + + +#include "aac_rom.h" +#include "dct.h" +#include "FDK_tools_rom.h" +#include "mdct.h" + +#define LDFB_HEADROOM 2 + +static void multE2_DinvF_fdk(INT_PCM *output, FIXP_DBL* x, const FIXP_WTB* fb, FIXP_DBL* z, const int N, const int stride) +{ + int i, scale; + + /* scale for FIXP_DBL -> INT_PCM conversion. */ + scale = (DFRACT_BITS - SAMPLE_BITS) - LDFB_HEADROOM; + + for(i=0;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 (SAMPLE_BITS <= 16) + FDK_ASSERT( (-WTS1-1 + scale) >= 0); + output[(N*3/4-1-i)*stride] = (INT_PCM)SATURATE_RIGHT_SHIFT(tmp, -WTS1-1 + scale, SAMPLE_BITS); +#else + FDK_ASSERT( (WTS1+1 - scale) >= 0); + output[(N*3/4-1-i)*stride] = (INT_PCM)SATURATE_LEFT_SHIFT(tmp, WTS1+1 - scale, SAMPLE_BITS); +#endif + + z[i] = z0; + z[N + i] = z2; + } + + for(i=N/4;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 (SAMPLE_BITS <= 16) + FDK_ASSERT( (-WTS0-1 + scale) >= 0); + output[(i-N/4)*stride] = (INT_PCM)SATURATE_RIGHT_SHIFT(tmp0, -WTS0-1 + scale, SAMPLE_BITS); + output[(N*3/4-1-i)*stride] = (INT_PCM)SATURATE_RIGHT_SHIFT(tmp1, -WTS1-1 + scale, SAMPLE_BITS); +#else + FDK_ASSERT( (WTS0+1 - scale) >= 0); + output[(i-N/4)*stride] = (INT_PCM)SATURATE_LEFT_SHIFT(tmp0, WTS0+1 - scale, SAMPLE_BITS); + output[(N*3/4-1-i)*stride] = (INT_PCM)SATURATE_LEFT_SHIFT(tmp1, WTS1+1 - scale, SAMPLE_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= 0); + output[(N*3/4 + i)*stride] = (INT_PCM)SATURATE_RIGHT_SHIFT(tmp0, -WTS0-1 + scale, SAMPLE_BITS); +#else + FDK_ASSERT( (WTS0+1 - scale) >= 0); + output[(N*3/4 + i)*stride] = (INT_PCM)SATURATE_LEFT_SHIFT(tmp0, WTS0+1 - scale, SAMPLE_BITS); +#endif + } +} + +int InvMdctTransformLowDelay_fdk (FIXP_DBL *mdctData, const int mdctData_e, INT_PCM *output, FIXP_DBL *fs_buffer, const int stride, 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 */ + + /* Select LD window slope */ + if (N == 512) + coef = (FIXP_WTB*)LowDelaySynthesis512; + else + coef = (FIXP_WTB*)LowDelaySynthesis480; + + /* + 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 (gain != (FIXP_DBL)0) { + scaleValuesWithFactor(mdctData, gain, N, scale); + } else { + scaleValues(mdctData, N, scale); + } + + /* Since all exponent and factors have been applied, current exponent is zero. */ + multE2_DinvF_fdk(output, mdctData, coef, fs_buffer, N, stride); + + return (1); +} + + + + -- cgit v1.2.3