/* ------------------------------------------------------------------ * 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: pvmp3_stereo_proc.cpp Functions: pvmp3_st_mid_side pvmp3_st_intensity pvmp3_stereo_proc ------------------------------------------------------------------------------ pvmp3_st_mid_side INPUT AND OUTPUT DEFINITIONS Input int32 xr[], input channel int32 xl[], int32 Start, Location of first element where stereo intensity is applied int32 Number number of elements affected Returns int32 xl[], generated stereo channel ------------------------------------------------------------------------------ pvmp3_st_intensity INPUT AND OUTPUT DEFINITIONS Input int32 xr[], input channel int32 xl[], int32 is_pos, index to table is_ratio_factor[] int32 Start, Location of first element where stereo intensity is applied int32 Number number of elements affected Returns int32 xl[], generated stereo channel ------------------------------------------------------------------------------ pvmp3_stereo_proc INPUT AND OUTPUT DEFINITIONS Input int32 xr[], input channel int32 xl[], mp3ScaleFactors *scalefac, scale factors structure struct gr_info_s *gr_info, granule structure mp3Header *info mp3 header info Returns int32 xl[], generated stereo channel ------------------------------------------------------------------------------ FUNCTION DESCRIPTION stereo processing for mpeg1 layer III After requantization, the reconstructed values are processed for ms_stereo or intensity_stereo modes or both, before passing them to the synthesis filterbank In ms_stereo mode the values of the normalized middle/side channels M[l] and S[l] are transmitted instead of the left/right channel values L[l] and R[l]. From here, L[l] and R[l] are reconstructed Intensity_stereo is done by specifying the magnitude (via the scalefactors of the left channel) and a stereo position is_pos[sfb], which is transmitted instead of scalefactors of the right channel. The stereo position is used to derive the left and right channel signals ------------------------------------------------------------------------------ REQUIREMENTS ------------------------------------------------------------------------------ REFERENCES [1] ISO MPEG Audio Subgroup Software Simulation Group (1996) ISO 13818-3 MPEG-2 Audio Decoder - Lower Sampling Frequency Extension ------------------------------------------------------------------------------ PSEUDO-CODE ------------------------------------------------------------------------------ */ /*---------------------------------------------------------------------------- ; INCLUDES ----------------------------------------------------------------------------*/ #include "pvmp3_stereo_proc.h" #include "pv_mp3dec_fxd_op.h" #include "pvmp3_tables.h" /*---------------------------------------------------------------------------- ; MACROS ; Define module specific macros here ----------------------------------------------------------------------------*/ /*---------------------------------------------------------------------------- ; DEFINES ; Include all pre-processor statements here. Include conditional ; compile variables also. ----------------------------------------------------------------------------*/ #define N31 31 #define Q31_fmt(a) (int32(double(0x7FFFFFFF)*(a))) /*---------------------------------------------------------------------------- ; LOCAL FUNCTION DEFINITIONS ; Function Prototype declaration ----------------------------------------------------------------------------*/ /*---------------------------------------------------------------------------- ; LOCAL STORE/BUFFER/POINTER DEFINITIONS ; Variable declaration - defined here and used outside this module ----------------------------------------------------------------------------*/ /* * TmpFac= tan(is_pos * (PI /12)); * * TmpFac /= (1 + TmpFac); * */ const int32 is_ratio_factor[8] = {0, Q31_fmt(0.21132486540519), Q31_fmt(0.36602540378444), Q31_fmt(0.50000000000000), Q31_fmt(0.63397459621556), Q31_fmt(0.78867513459481), Q31_fmt(1.00000000000000), 0 }; /*---------------------------------------------------------------------------- ; 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 ----------------------------------------------------------------------------*/ #if __has_attribute(no_sanitize) // deliberately playing near overflow points of int32 __attribute__((no_sanitize("integer"))) #endif void pvmp3_st_mid_side(int32 xr[SUBBANDS_NUMBER*FILTERBANK_BANDS], int32 xl[SUBBANDS_NUMBER*FILTERBANK_BANDS], int32 Start, int32 Number) { int32 *pt_xr = &xr[Start]; int32 *pt_xl = &xl[Start]; for (int32 i = Number >> 1; i != 0; i--) { int32 xxr = *(pt_xr) << 1; int32 xxl = *(pt_xl) << 1; *(pt_xr++) = fxp_mul32_Q32((xxr + xxl), Q31_fmt(0.70710678118655)); /* Sum */ *(pt_xl++) = fxp_mul32_Q32((xxr - xxl), Q31_fmt(0.70710678118655)); /* Diff */ xxr = *(pt_xr) << 1; xxl = *(pt_xl) << 1; *(pt_xr++) = fxp_mul32_Q32((xxr + xxl), Q31_fmt(0.70710678118655)); /* Sum */ *(pt_xl++) = fxp_mul32_Q32((xxr - xxl), Q31_fmt(0.70710678118655)); /* Diff */ } if (Number&1) { int32 xxr = *(pt_xr) << 1; int32 xxl = *(pt_xl) << 1; *(pt_xr) = fxp_mul32_Q32((xxr + xxl), Q31_fmt(0.70710678118655)); /* Sum */ *(pt_xl) = fxp_mul32_Q32((xxr - xxl), Q31_fmt(0.70710678118655)); /* Diff */ } } /*---------------------------------------------------------------------------- ; FUNCTION CODE ----------------------------------------------------------------------------*/ // deliberately plays near overflow points of int32 #if __has_attribute(no_sanitize) __attribute__((no_sanitize("integer"))) #endif void pvmp3_st_intensity(int32 xr[SUBBANDS_NUMBER*FILTERBANK_BANDS], int32 xl[SUBBANDS_NUMBER*FILTERBANK_BANDS], int32 is_pos, int32 Start, int32 Number) { int32 TmpFac = is_ratio_factor[ is_pos & 7]; int32 *pt_xr = &xr[Start]; int32 *pt_xl = &xl[Start]; for (int32 i = Number >> 1; i != 0; i--) { int32 tmp = fxp_mul32_Q32((*pt_xr) << 1, TmpFac); *(pt_xl++) = (*pt_xr) - tmp; *(pt_xr++) = tmp; tmp = fxp_mul32_Q32((*pt_xr) << 1, TmpFac); *(pt_xl++) = (*pt_xr) - tmp; *(pt_xr++) = tmp; } if (Number&1) { int32 tmp = fxp_mul32_Q32((*pt_xr) << 1, TmpFac); *(pt_xl) = (*pt_xr) - tmp; *(pt_xr) = tmp; } } /*---------------------------------------------------------------------------- ; FUNCTION CODE ----------------------------------------------------------------------------*/ void pvmp3_stereo_proc(int32 xr[SUBBANDS_NUMBER*FILTERBANK_BANDS], int32 xl[SUBBANDS_NUMBER*FILTERBANK_BANDS], mp3ScaleFactors *scalefac, granuleInfo *gr_info, int32 used_freq_lines, mp3Header *info) { int32 sb; int32 ss; int32 sfbNo; int32 sfbStart; int32 sfb; int32 sfbTemp; int32 i; int32 j; int32 i_stereo = (info->mode == MPG_MD_JOINT_STEREO) && (info->mode_ext & 0x1); int32 ms_stereo = (info->mode == MPG_MD_JOINT_STEREO) && (info->mode_ext & 0x2); int32 sfreq = info->version_x + (info->version_x << 1); sfreq += info->sampling_frequency; if (i_stereo) { if (gr_info->window_switching_flag && (gr_info->block_type == 2)) { if (gr_info->mixed_block_flag) { /* * mixed blocks processing */ i = 31; ss = 17; sb = 0; while (i >= 0) { if (xl[(i*FILTERBANK_BANDS) + ss]) { sb = (i << 4) + (i << 1) + ss; i = -1; } else { ss--; if (ss < 0) { i--; ss = 17; } } } if (sb < 36) { /* * mixed blocks processing: intensity bound inside long blocks */ /* 1. long blocks up to intensity border: not intensity */ if (mp3_sfBandIndex[sfreq].l[4] <= sb) { sfb = 4; } else { sfb = 0; } while (mp3_sfBandIndex[sfreq].l[sfb] < sb) { sfb++; } /* from that sfb on intensity stereo */ sfbTemp = sfb; /* save for later use */ sfbStart = mp3_sfBandIndex[sfreq].l[sfb]; /* from 0 up to sfbStart do ms_stereo or normal stereo */ if (ms_stereo) { pvmp3_st_mid_side(xr, xl, 0, sfbStart); } /* 2. long blocks from intensity border up to sfb band 8: intensity */ /* calc. is_ratio */ /* Start of intensity stereo of remaining sfc bands: */ for (; sfbTemp < 8; sfbTemp++) { sfbStart = mp3_sfBandIndex[sfreq].l[sfbTemp]; /* = Start in 0 ... 575 */ sfbNo = mp3_sfBandIndex[sfreq].l[sfbTemp+1] - mp3_sfBandIndex[sfreq].l[sfbTemp]; /* No of lines to process */ if (scalefac->l[sfbTemp] != 7) { pvmp3_st_intensity(xr, xl, scalefac->l[sfbTemp], sfbStart, sfbNo); } else if (ms_stereo) { pvmp3_st_mid_side(xr, xl, sfbStart, sfbNo); } } /* for (; sfbTemp < 8; sfbTemp++) */ for (j = 0; j < 3; j++) { /* 3. short blocks from sfbcnt to last sfb do intensity stereo */ for (sfbTemp = 3; sfbTemp < 13; sfbTemp++) { sfbNo = mp3_sfBandIndex[sfreq].s[sfbTemp+1] - mp3_sfBandIndex[sfreq].s[sfbTemp]; /* No of lines to process */ sfbStart = 3 * mp3_sfBandIndex[sfreq].s[sfbTemp] + j * sfbNo; if (scalefac->s[j][sfbTemp] != 7) { pvmp3_st_intensity(xr, xl, scalefac->s[j][sfbTemp], sfbStart, sfbNo); } else if (ms_stereo) { pvmp3_st_mid_side(xr, xl, sfbStart, sfbNo); } } /* for (; sfbTemp < 22; sfbTemp++) */ } /* for (j = 0; j < 3; j++) */ } else /* else for (sb >= 36) */ { /* * mixed blocks processing: intensity bound outside long blocks */ /* * 2. short blocks from sfb band 3 up to intensity border: normal stereo, ms stereo and intensity */ for (j = 0; j < 3; j++) { int32 sfbcnt; sfbcnt = -1; for (sfb = 12; sfb >= 3; sfb--) { int32 lines; lines = mp3_sfBandIndex[sfreq].s[sfb+1] - mp3_sfBandIndex[sfreq].s[sfb]; i = 3 * mp3_sfBandIndex[sfreq].s[sfb] + (j + 1) * lines - 1; while (lines > 0) { if (xl[i]) { sfbcnt = sfb; sfb = -10; lines = -10; } lines--; i--; } } sfbcnt += 1; if (sfbcnt < 3) { sfbcnt = 3; } sfbTemp = sfbcnt; /* for later use */ /* * do normal stereo or MS stereo from sfb 3 to < sfbcnt: */ for (sb = 3; sb < sfbcnt; sb++) { sfbNo = mp3_sfBandIndex[sfreq].s[sb+1] - mp3_sfBandIndex[sfreq].s[sb]; sfbStart = 3 * mp3_sfBandIndex[sfreq].s[sb] + j * sfbNo; if (ms_stereo) { pvmp3_st_mid_side(xr, xl, sfbStart, sfbNo); } } /* from sfbcnt to last sfb do intensity stereo */ for (; sfbTemp < 13; sfbTemp++) { sfbNo = mp3_sfBandIndex[sfreq].s[sfbTemp+1] - mp3_sfBandIndex[sfreq].s[sfbTemp]; /* No of lines to process */ sfbStart = 3 * mp3_sfBandIndex[sfreq].s[sfbTemp] + j * sfbNo; if (scalefac->s[j][sfbTemp] != 7) { pvmp3_st_intensity(xr, xl, scalefac->s[j][sfbTemp], sfbStart, sfbNo); } else if (ms_stereo) { pvmp3_st_mid_side(xr, xl, sfbStart, sfbNo); } } /* for (; sfbTemp < 22; sfbTemp++) */ } /* for (j = 0; j < 3; j++) */ /* 1. long blocks up to sfb band 8: not intensity */ /* from 0 to sfb 8 ms_stereo or normal stereo */ sfbStart = mp3_sfBandIndex[sfreq].l[8]; if (ms_stereo) { pvmp3_st_mid_side(xr, xl, 0, sfbStart); } } } /* if (gr_info->mixed_block_flag) */ else { /* * short block processing */ for (j = 0; j < 3; j++) { int32 sfbcnt = -1; for (sfb = 12; sfb >= 0; sfb--) { int32 lines = mp3_sfBandIndex[sfreq].s[sfb+1] - mp3_sfBandIndex[sfreq].s[sfb]; i = 3 * mp3_sfBandIndex[sfreq].s[sfb] + (j + 1) * lines - 1; while (lines > 0) { if (xl[i]) { sfbcnt = sfb; sfb = -10; lines = -10; } lines--; i--; } } sfbcnt += 1; sfbTemp = sfbcnt; /* for later use */ /* do normal stereo or MS stereo from 0 to sfbcnt */ for (sb = 0; sb < sfbcnt; sb++) { sfbNo = mp3_sfBandIndex[sfreq].s[sb+1] - mp3_sfBandIndex[sfreq].s[sb]; sfbStart = 3 * mp3_sfBandIndex[sfreq].s[sb] + j * sfbNo; if (ms_stereo) { pvmp3_st_mid_side(xr, xl, sfbStart, sfbNo); } } /* from sfbcnt to last sfb do intensity stereo */ for (; sfbTemp < 13; sfbTemp++) { sfbNo = mp3_sfBandIndex[sfreq].s[sfbTemp+1] - mp3_sfBandIndex[sfreq].s[sfbTemp]; /* No of lines to process */ sfbStart = 3 * mp3_sfBandIndex[sfreq].s[sfbTemp] + j * sfbNo; if (scalefac->s[j][sfbTemp] != 7) { pvmp3_st_intensity(xr, xl, scalefac->s[j][sfbTemp], sfbStart, sfbNo); } else if (ms_stereo) { pvmp3_st_mid_side(xr, xl, sfbStart, sfbNo); } } /* for (; sfbTemp < 22; sfbTemp++) */ } /* for (j = 0; j < 3; j++) */ } /* if( gr_info->mixed_block_flag) */ } /* if (gr_info->window_switching_flag && (gr_info->block_type == 2)) */ else { /* * long block processing */ i = 31; ss = 17; sb = 0; while (i >= 0) { if (xl[(i*FILTERBANK_BANDS) + ss] != 0) { sb = (i << 4) + (i << 1) + ss; i = -2; } else { ss--; if (ss < 0) { i--; ss = 17; } } } if (sb) { if (mp3_sfBandIndex[sfreq].l[14] <= sb) { sfb = 14; } else if (mp3_sfBandIndex[sfreq].l[7] <= sb) { sfb = 7; } else { sfb = 0; } while (mp3_sfBandIndex[sfreq].l[sfb] <= sb) { sfb++; } } else { if (i == -1) { /* all xr[1][][] are 0: set IS bound sfb to 0 */ sfb = 0; } else { /* xr[1][0][0] is unequal 0 and all others are 0: set IS bound sfb to 1 */ sfb = 1; } } sfbTemp = sfb; /* save for later use */ sfbStart = mp3_sfBandIndex[sfreq].l[sfb]; /* from 0 to sfbStart ms_stereo or normal stereo */ if (ms_stereo) { pvmp3_st_mid_side(xr, xl, 0, sfbStart); } /* now intensity stereo of the remaining sfb's: */ for (; sfb < 21; sfb++) { sfbStart = mp3_sfBandIndex[sfreq].l[sfb]; sfbNo = mp3_sfBandIndex[sfreq].l[sfb+1] - mp3_sfBandIndex[sfreq].l[sfb]; /* No of lines to process */ if (scalefac->l[sfb] != 7) { pvmp3_st_intensity(xr, xl, scalefac->l[sfb], sfbStart, sfbNo); } else if (ms_stereo) { pvmp3_st_mid_side(xr, xl, sfbStart, sfbNo); } } /* for (; sfbTemp < 22; sfbTemp++) */ sfbStart = mp3_sfBandIndex[sfreq].l[21]; sfbNo = mp3_sfBandIndex[sfreq].l[22] - mp3_sfBandIndex[sfreq].l[21]; /* No of lines to process */ if (scalefac->l[21] != 7) { if (sfbTemp < 21) { sfbTemp = scalefac->l[20]; } else { sfbTemp = 0; /* if scalefac[20] is not an intensity position, is_pos = 0 */ } pvmp3_st_intensity(xr, xl, sfbTemp, sfbStart, sfbNo); } else if (ms_stereo) { pvmp3_st_mid_side(xr, xl, sfbStart, sfbNo); } } /* if (gr_info->window_switching_flag && (gr_info->block_type == 2)) */ } /* if (i_stereo) */ else { /* * normal or ms stereo processing */ if (ms_stereo) { pvmp3_st_mid_side(xr, xl, 0, used_freq_lines); } } /* if (i_stereo) */ }