/* ------------------------------------------------------------------ * Copyright (C) 1998-2009 PacketVideo * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either * express or implied. * See the License for the specific language governing permissions * and limitations under the License. * ------------------------------------------------------------------- */ /* Filename: ps_hybrid_analysis.c ------------------------------------------------------------------------------ REVISION HISTORY Who: Date: MM/DD/YYYY Description: ------------------------------------------------------------------------------ INPUT AND OUTPUT DEFINITIONS ------------------------------------------------------------------------------ FUNCTION DESCRIPTION Does Hybrid analysis: Get higher frequency resolution in the lower QMF subbands creating sub-subbands. This is done by low frequency filtering. Lower QMF subbands are further split in order to obtain a higher frequency resolution, enabling a proper stereo analysis and synthesis for the lower frequencies. Two hybrid are defined. Both filters have length 13 and a delay of 6. In this implementation, the symmetry of the filters helps to simplify the design. Increase Freq. Resolution _______ ________ | | _______ | | ->|Hybrid | LF ---- | |->| Hybrid |--> | Anal. | | | | | Synth | QMF -> L ------- o----------------------->| | -------- Synth QMF | s_k(n) |Stereo |--------------> Anal. -------------------------->| | _______ | | | | ________ | | HF --o | ----------- |Process| | | ->| Delay | | ->| |-------->| |->| Hybrid |--> ------- | |decorrelate| d_k(n) | | | Synth | QMF -> R ---->| |-------->| | -------- Synth ----------- |_______|--------------> subband k QMF channel 0 ................. 0 ----------- 1 ................. 0 2 ................. 0 3 ................. 0 4 ................. 0 5 ................. 0 Sub-QMF ( Increase Freq. Resolution) 6 ................. 1 7 ................. 1 8 ................. 2 9 ................. 2 10 ................. 3 ----------- 11 ................. 4 12 ................. 5 13 ................. 6 14 ................. 7 15 ................. 8 QMF 16-17 ................. 9-10 18-20 ................. 11-13 21-24 ................. 14-17 25-29 ................. 18-22 30-41 ................. 23-34 42-70 ................. 35-63 ----------- ------------------------------------------------------------------------------ REQUIREMENTS ------------------------------------------------------------------------------ REFERENCES SC 29 Software Copyright Licencing Disclaimer: This software module was originally developed by Coding Technologies and edited by - in the course of development of the ISO/IEC 13818-7 and ISO/IEC 14496-3 standards for reference purposes and its performance may not have been optimized. This software module is an implementation of one or more tools as specified by the ISO/IEC 13818-7 and ISO/IEC 14496-3 standards. ISO/IEC gives users free license to this software module or modifications thereof for use in products claiming conformance to audiovisual and image-coding related ITU Recommendations and/or ISO/IEC International Standards. ISO/IEC gives users the same free license to this software module or modifications thereof for research purposes and further ISO/IEC standardisation. Those intending to use this software module in products are advised that its use may infringe existing patents. ISO/IEC have no liability for use of this software module or modifications thereof. Copyright is not released for products that do not conform to audiovisual and image-coding related ITU Recommendations and/or ISO/IEC International Standards. The original developer retains full right to modify and use the code for its own purpose, assign or donate the code to a third party and to inhibit third parties from using the code for products that do not conform to audiovisual and image-coding related ITU Recommendations and/or ISO/IEC International Standards. This copyright notice must be included in all copies or derivative works. Copyright (c) ISO/IEC 2003. ------------------------------------------------------------------------------ PSEUDO-CODE ------------------------------------------------------------------------------ */ /*---------------------------------------------------------------------------- ; INCLUDES ----------------------------------------------------------------------------*/ #ifdef AAC_PLUS #ifdef PARAMETRICSTEREO #include "s_hybrid.h" #include "aac_mem_funcs.h" #include "ps_channel_filtering.h" #include "ps_hybrid_analysis.h" /*---------------------------------------------------------------------------- ; MACROS ; Define module specific macros here ----------------------------------------------------------------------------*/ /*---------------------------------------------------------------------------- ; DEFINES ; Include all pre-processor statements here. Include conditional ; compile variables also. ----------------------------------------------------------------------------*/ /*---------------------------------------------------------------------------- ; LOCAL FUNCTION DEFINITIONS ; Function Prototype declaration ----------------------------------------------------------------------------*/ /*---------------------------------------------------------------------------- ; LOCAL STORE/BUFFER/POINTER DEFINITIONS ; Variable declaration - defined here and used outside this module ----------------------------------------------------------------------------*/ /*---------------------------------------------------------------------------- ; EXTERNAL FUNCTION REFERENCES ; Declare functions defined elsewhere and referenced in this module ----------------------------------------------------------------------------*/ /*---------------------------------------------------------------------------- ; EXTERNAL GLOBAL STORE/BUFFER/POINTER REFERENCES ; Declare variables used in this module but defined elsewhere ----------------------------------------------------------------------------*/ /*---------------------------------------------------------------------------- ; FUNCTION CODE ----------------------------------------------------------------------------*/ void ps_hybrid_analysis(const Int32 mQmfReal[][64], const Int32 mQmfImag[][64], Int32 *mHybridReal, Int32 *mHybridImag, HYBRID *pHybrid, Int32 scratch_mem[], Int32 i) { Int32 band; HYBRID_RES hybridRes; Int32 chOffset = 0; Int32 *ptr_mHybrid_Re; Int32 *ptr_mHybrid_Im; Int32 *pt_mQmfBufferReal; Int32 *pt_mQmfBufferImag; pt_mQmfBufferReal = &scratch_mem[32 + i]; for (band = 0; band < pHybrid->nQmfBands; band++) { pt_mQmfBufferImag = pt_mQmfBufferReal + 44; pt_mQmfBufferReal[HYBRID_FILTER_LENGTH_m_1] = mQmfReal[HYBRID_FILTER_DELAY][band]; pt_mQmfBufferImag[HYBRID_FILTER_LENGTH_m_1] = mQmfImag[HYBRID_FILTER_DELAY][band]; ptr_mHybrid_Re = &mHybridReal[ chOffset]; ptr_mHybrid_Im = &mHybridImag[ chOffset]; hybridRes = (HYBRID_RES)pHybrid->pResolution[band]; switch (hybridRes) { /* * For QMF band = 1 and 2 */ case HYBRID_2_REAL: two_ch_filtering(pt_mQmfBufferReal, pt_mQmfBufferImag, ptr_mHybrid_Re, ptr_mHybrid_Im); chOffset += 2; break; /* * For QMF band = 0 */ case HYBRID_8_CPLX: eight_ch_filtering(pt_mQmfBufferReal, pt_mQmfBufferImag, pHybrid->mTempReal, pHybrid->mTempImag, scratch_mem); pv_memmove(ptr_mHybrid_Re, pHybrid->mTempReal, 4*sizeof(*pHybrid->mTempReal)); ptr_mHybrid_Re += 2; *(ptr_mHybrid_Re++) += pHybrid->mTempReal[5]; *(ptr_mHybrid_Re++) += pHybrid->mTempReal[4]; *(ptr_mHybrid_Re++) = pHybrid->mTempReal[6]; *(ptr_mHybrid_Re) = pHybrid->mTempReal[7]; pv_memmove(ptr_mHybrid_Im, pHybrid->mTempImag, 4*sizeof(*pHybrid->mTempImag)); ptr_mHybrid_Im += 2; *(ptr_mHybrid_Im++) += pHybrid->mTempImag[5]; *(ptr_mHybrid_Im++) += pHybrid->mTempImag[4]; *(ptr_mHybrid_Im++) = pHybrid->mTempImag[6]; *(ptr_mHybrid_Im) = pHybrid->mTempImag[7]; chOffset += 6; break; default: ; } pt_mQmfBufferReal = pt_mQmfBufferImag + 44; } } #endif #endif