| /* ------------------------------------------------------------------ |
| * 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. |
| * ------------------------------------------------------------------- |
| */ |
| /* |
| ------------------------------------------------------------------------------ |
| |
| PacketVideo Corp. |
| MP3 Decoder Library |
| Filename: mdct_18.cpp |
| |
| Date: 09/21/2007 |
| |
| ------------------------------------------------------------------------------ |
| REVISION HISTORY |
| |
| |
| Description: |
| |
| ------------------------------------------------------------------------------ |
| INPUT AND OUTPUT DEFINITIONS |
| |
| Input |
| int32 vec[], input vector of length 6 |
| int32 *history input for overlap and add, vector updated with |
| next overlap and add values |
| Returns |
| none mdct computation in-place |
| |
| |
| ------------------------------------------------------------------------------ |
| FUNCTION DESCRIPTION |
| |
| Returns the mdct of length 6 of the input vector, as well as the overlap |
| vector for next iteration ( on history[]) |
| |
| ------------------------------------------------------------------------------ |
| REQUIREMENTS |
| |
| |
| ------------------------------------------------------------------------------ |
| REFERENCES |
| |
| ------------------------------------------------------------------------------ |
| PSEUDO-CODE |
| |
| ------------------------------------------------------------------------------ |
| */ |
| |
| |
| /*---------------------------------------------------------------------------- |
| ; INCLUDES |
| ----------------------------------------------------------------------------*/ |
| |
| #include "pv_mp3dec_fxd_op.h" |
| #include "pvmp3_mdct_6.h" |
| |
| |
| /*---------------------------------------------------------------------------- |
| ; MACROS |
| ; Define module specific macros here |
| ----------------------------------------------------------------------------*/ |
| |
| |
| /*---------------------------------------------------------------------------- |
| ; DEFINES |
| ; Include all pre-processor statements here. Include conditional |
| ; compile variables also. |
| ----------------------------------------------------------------------------*/ |
| #define QFORMAT 29 |
| #define Qfmt29(a) (int32)((a)*((int32)1<<QFORMAT) + ((a)>=0?0.5F:-0.5F)) |
| |
| /*---------------------------------------------------------------------------- |
| ; LOCAL FUNCTION DEFINITIONS |
| ; Function Prototype declaration |
| ----------------------------------------------------------------------------*/ |
| |
| /*---------------------------------------------------------------------------- |
| ; LOCAL STORE/BUFFER/POINTER DEFINITIONS |
| ; Variable declaration - defined here and used outside this module |
| ----------------------------------------------------------------------------*/ |
| /* |
| * (1./(2*cos((pi/(2*N))*(2*i+1)))), N = 12, i = [0:N/2-1] |
| */ |
| |
| const int32 cosTerms_1_ov_cos_phi_N6[6] = |
| { |
| |
| Qfmt29(0.50431448029008f), Qfmt29(0.54119610014620f), |
| Qfmt29(0.63023620700513f), Qfmt29(0.82133981585229f), |
| Qfmt29(1.30656296487638f), Qfmt29(3.83064878777019f) |
| }; |
| |
| /*---------------------------------------------------------------------------- |
| ; 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 pvmp3_mdct_6(int32 vec[], int32 *history) |
| { |
| int32 i; |
| int32 tmp; |
| int32 tmp1; |
| int32 tmp2; |
| |
| int32 *pt_vec = vec; |
| int32 *pt_vec_o = vec; |
| const int32 *pt_cos = cosTerms_1_ov_cos_phi_N6; |
| |
| for (i = 2; i != 0; i--) |
| { |
| tmp = *(pt_vec++); |
| tmp1 = *(pt_vec++); |
| tmp2 = *(pt_vec++); |
| *(pt_vec_o++) = fxp_mul32_Q29(tmp, *(pt_cos++)); |
| *(pt_vec_o++) = fxp_mul32_Q29(tmp1, *(pt_cos++)); |
| *(pt_vec_o++) = fxp_mul32_Q29(tmp2, *(pt_cos++)); |
| } |
| |
| |
| pvmp3_dct_6(vec); // Even terms |
| |
| |
| tmp = -(vec[0] + vec[1]); |
| history[3] = tmp; |
| history[2] = tmp; |
| tmp = -(vec[1] + vec[2]); |
| vec[0] = vec[3] + vec[4]; |
| vec[1] = vec[4] + vec[5]; |
| history[4] = tmp; |
| history[1] = tmp; |
| tmp = -(vec[2] + vec[3]); |
| vec[4] = -vec[1]; |
| history[5] = tmp; |
| history[0] = tmp; |
| |
| vec[2] = vec[5]; |
| vec[3] = -vec[5]; |
| vec[5] = -vec[0]; |
| |
| } |
| |