| /* ------------------------------------------------------------------ |
| * 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_imdct_synth.cpp |
| |
| Date: 09/21/2007 |
| |
| ------------------------------------------------------------------------------ |
| REVISION HISTORY |
| |
| |
| Description: |
| |
| ------------------------------------------------------------------------------ |
| INPUT AND OUTPUT DEFINITIONS |
| |
| Input |
| int32 in[], Pointer to spec values of current channel |
| int32 overlap[], Pointer to overlap values of current channel |
| uint32 blk_type, Block type |
| int16 mx_band, In case of mixed blocks, # of bands with long |
| blocks (2 or 4) else 0 |
| int32 *Scratch_mem |
| Returns |
| |
| int32 in[], |
| |
| ------------------------------------------------------------------------------ |
| FUNCTION DESCRIPTION |
| |
| The frequency lines are preprocessed by the "alias reduction" scheme |
| and fed into the IMDCT matrix, each 18 into one transform block. |
| The first half of the output values are added to the stored overlap |
| values from the last block. These values are new output values and |
| are input values for the polyphase filterbank. The second half of the |
| output values is stored for overlap with the next data granule. |
| The number of windowed samples is 12 for short blocks, and 36 for long |
| blocks |
| |
| Windowing |
| |
| Depending on window_switching_flag[gr][ch], block_type[gr][ch] and |
| mixed_block_flag[gr][ch] different shapes of windows are used. |
| normal window |
| start window |
| stop window |
| short windows |
| Each of the three short blocks is windowed separately. |
| The windowed short blocks must be overlapped and concatenated. |
| |
| Overlapping and adding with previous block |
| |
| The first half (18 values) of the current block (36 values) has to be |
| overlapped with the second half of the previous block. The second half |
| of the current block has to be stored for overlapping with the next block |
| |
| ------------------------------------------------------------------------------ |
| 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_imdct_synth.h" |
| #include "pv_mp3dec_fxd_op.h" |
| #include "pvmp3_dec_defs.h" |
| #include "pvmp3_mdct_18.h" |
| #include "pvmp3_mdct_6.h" |
| #include "mp3_mem_funcs.h" |
| |
| |
| |
| /*---------------------------------------------------------------------------- |
| ; MACROS |
| ; Define module specific macros here |
| ----------------------------------------------------------------------------*/ |
| |
| |
| /*---------------------------------------------------------------------------- |
| ; DEFINES |
| ; Include all pre-processor statements here. Include conditional |
| ; compile variables also. |
| ----------------------------------------------------------------------------*/ |
| #define LONG 0 |
| #define START 1 |
| #define SHORT 2 |
| #define STOP 3 |
| |
| /*---------------------------------------------------------------------------- |
| ; LOCAL FUNCTION DEFINITIONS |
| ; Function Prototype declaration |
| ----------------------------------------------------------------------------*/ |
| |
| /*---------------------------------------------------------------------------- |
| ; LOCAL STORE/BUFFER/POINTER DEFINITIONS |
| ; Variable declaration - defined here and used outside this module |
| ----------------------------------------------------------------------------*/ |
| /* |
| * sin(pi/36*(k+0.5)),k=0..35 |
| */ |
| |
| const int32 normal_win[36] = |
| { |
| Qfmt_31(0.08723877473068f), Qfmt_31(0.26105238444010f), Qfmt_31(0.43287922787620f), |
| Qfmt_31(0.60141159900854f), Qfmt_31(0.76536686473018f), Qfmt_31(0.92349722647006f), |
| Qfmt_31(0.53729960834682f), Qfmt_31(0.60876142900872f), Qfmt_31(0.67559020761566f), |
| Qfmt_31(-0.73727733681012f), Qfmt_31(-0.79335334029124f), Qfmt_31(0.84339144581289f), |
| Qfmt_31(0.88701083317822f), Qfmt_31(0.92387953251129f), Qfmt_31(-0.95371695074823f), |
| Qfmt_31(-0.97629600711993f), Qfmt_31(-0.99144486137381f), Qfmt_31(-0.99904822158186f), |
| Qfmt_31(0.99904822158186f), Qfmt_31(0.99144486137381f), Qfmt_31(0.97629600711993f), |
| Qfmt_31(0.95371695074823f), Qfmt_31(0.92387953251129f), Qfmt_31(0.88701083317822f), |
| Qfmt_31(0.84339144581289f), Qfmt_31(0.79335334029124f), Qfmt_31(0.73727733681012f), |
| Qfmt_31(0.67559020761566f), Qfmt_31(0.60876142900872f), Qfmt_31(0.53729960834682f), |
| Qfmt_31(0.46174861323503f), Qfmt_31(0.38268343236509f), Qfmt_31(0.30070579950427f), |
| Qfmt_31(0.21643961393810f), Qfmt_31(0.13052619222005f), Qfmt_31(0.04361938736534f) |
| }; |
| |
| |
| const int32 start_win[36] = |
| { |
| /* k=0..17 sin(pi/36*(k+0.5)), */ |
| Qfmt_31(0.08723877473068f), Qfmt_31(0.26105238444010f), Qfmt_31(0.43287922787620f), |
| Qfmt_31(0.60141159900854f), Qfmt_31(0.76536686473018f), Qfmt_31(0.92349722647006f), |
| Qfmt_31(0.53729960834682f), Qfmt_31(0.60876142900872f), Qfmt_31(0.67559020761566f), |
| Qfmt_31(-0.73727733681012f), Qfmt_31(-0.79335334029124f), Qfmt_31(0.84339144581289f), |
| Qfmt_31(0.88701083317822f), Qfmt_31(0.92387953251129f), Qfmt_31(-0.95371695074823f), |
| Qfmt_31(-0.97629600711993f), Qfmt_31(-0.99144486137381f), Qfmt_31(-0.99904822158186f), |
| |
| Qfmt_31(0.99999990000000f), Qfmt_31(0.99999990000000f), Qfmt_31(0.99999990000000f), |
| Qfmt_31(0.99999990000000f), Qfmt_31(0.99999990000000f), Qfmt_31(0.99999990000000f), |
| /* k=24..29; sin(pi/12*(k-18+0.5)) */ |
| Qfmt_31(0.99144486137381f), Qfmt_31(0.92387953251129f), Qfmt_31(0.79335334029124f), |
| Qfmt_31(0.60876142900872f), Qfmt_31(0.38268343236509f), Qfmt_31(0.13052619222005f), |
| |
| Qfmt_31(0.00000000000000f), Qfmt_31(0.00000000000000f), Qfmt_31(0.00000000000000f), |
| Qfmt_31(0.00000000000000f), Qfmt_31(0.00000000000000f), Qfmt_31(0.00000000000000f) |
| }; |
| |
| |
| const int32 stop_win[36] = |
| { |
| Qfmt_31(0.00000000000000f), Qfmt_31(0.00000000000000f), Qfmt_31(0.00000000000000f), |
| Qfmt_31(0.00000000000000f), Qfmt_31(0.00000000000000f), Qfmt_31(0.00000000000000f), |
| /* k=6..11; sin(pi/12*(k-6+0.5)) */ |
| Qfmt_31(0.13052619222005f), Qfmt_31(0.38268343236509f), Qfmt_31(0.60876142900872f), |
| Qfmt_31(-0.79335334029124f), Qfmt_31(-0.92387953251129f), Qfmt_31(0.99144486137381f), |
| |
| Qfmt_31(0.99999990000000f), Qfmt_31(0.99999990000000f), Qfmt_31(-0.99999990000000f), |
| Qfmt_31(-0.99999990000000f), Qfmt_31(-0.99999990000000f), Qfmt_31(-0.99999990000000f), |
| /* k=18..35 sin(pi/36*(k+0.5)), */ |
| Qfmt_31(0.99904822158186f), Qfmt_31(0.99144486137381f), Qfmt_31(0.97629600711993f), |
| Qfmt_31(0.95371695074823f), Qfmt_31(0.92387953251129f), Qfmt_31(0.88701083317822f), |
| Qfmt_31(0.84339144581289f), Qfmt_31(0.79335334029124f), Qfmt_31(0.73727733681012f), |
| Qfmt_31(0.67559020761566f), Qfmt_31(0.60876142900872f), Qfmt_31(0.53729960834682f), |
| Qfmt_31(0.46174861323503f), Qfmt_31(0.38268343236509f), Qfmt_31(0.30070579950427f), |
| Qfmt_31(0.21643961393810f), Qfmt_31(0.13052619222005f), Qfmt_31(0.04361938736534f) |
| }; |
| |
| |
| const int32 short_win[12] = |
| { |
| /* k=0..11; sin(pi/12*(k+0.5)) */ |
| Qfmt_31(0.13052619222005f), Qfmt_31(0.38268343236509f), Qfmt_31(0.60876142900872f), |
| Qfmt_31(0.79335334029124f), Qfmt_31(0.92387953251129f), Qfmt_31(0.99144486137381f), |
| Qfmt_31(0.99144486137381f), Qfmt_31(0.92387953251129f), Qfmt_31(0.79335334029124f), |
| Qfmt_31(0.60876142900872f), Qfmt_31(0.38268343236509f), Qfmt_31(0.13052619222005f), |
| }; |
| /*---------------------------------------------------------------------------- |
| ; 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_imdct_synth(int32 in[SUBBANDS_NUMBER*FILTERBANK_BANDS], |
| int32 overlap[SUBBANDS_NUMBER*FILTERBANK_BANDS], |
| uint32 blk_type, |
| int16 mx_band, |
| int32 used_freq_lines, |
| int32 *Scratch_mem) |
| { |
| |
| int32 band; |
| int32 bands2process = used_freq_lines + 2; |
| |
| if (bands2process > SUBBANDS_NUMBER) |
| { |
| bands2process = SUBBANDS_NUMBER; /* default */ |
| } |
| |
| |
| /* |
| * in case of mx_poly_band> 0, do |
| * long transforms |
| */ |
| |
| |
| for (band = 0; band < bands2process; band++) |
| { |
| uint32 current_blk_type = (band < mx_band) ? LONG : blk_type; |
| |
| int32 * out = in + (band * FILTERBANK_BANDS); |
| int32 * history = overlap + (band * FILTERBANK_BANDS); |
| |
| switch (current_blk_type) |
| { |
| case LONG: |
| |
| pvmp3_mdct_18(out, history, normal_win); |
| |
| break; |
| |
| case START: |
| |
| pvmp3_mdct_18(out, history, start_win); |
| |
| break; |
| |
| case STOP: |
| |
| pvmp3_mdct_18(out, history, stop_win); |
| |
| break; |
| |
| case SHORT: |
| { |
| int32 *tmp_prev_ovr = &Scratch_mem[FILTERBANK_BANDS]; |
| int32 i; |
| |
| for (i = 0; i < 6; i++) |
| { |
| Scratch_mem[i ] = out[(i*3)]; |
| Scratch_mem[6 +i] = out[(i*3) + 1]; |
| Scratch_mem[12 +i] = out[(i*3) + 2]; |
| } |
| |
| pvmp3_mdct_6(&Scratch_mem[ 0], &tmp_prev_ovr[ 0]); |
| pvmp3_mdct_6(&Scratch_mem[ 6], &tmp_prev_ovr[ 6]); |
| pvmp3_mdct_6(&Scratch_mem[12], &tmp_prev_ovr[12]); |
| |
| for (i = 0; i < 6; i++) |
| { |
| int32 temp = history[i]; |
| /* next iteration overlap */ |
| history[i] = fxp_mul32_Q32(tmp_prev_ovr[ 6+i] << 1, short_win[6+i]); |
| history[i] += fxp_mul32_Q32(Scratch_mem[12+i] << 1, short_win[ i]); |
| out[i] = temp; |
| } |
| |
| for (i = 0; i < 6; i++) |
| { |
| out[i+6] = fxp_mul32_Q32(Scratch_mem[i] << 1, short_win[i]); |
| out[i+6] += history[i+6]; |
| /* next iteration overlap */ |
| history[i+6] = fxp_mul32_Q32(tmp_prev_ovr[12+i] << 1, short_win[6+i]); |
| |
| } |
| for (i = 0; i < 6; i++) |
| { |
| out[i+12] = fxp_mul32_Q32(tmp_prev_ovr[ i] << 1, short_win[6+i]); |
| out[i+12] += fxp_mul32_Q32(Scratch_mem[6+i] << 1, short_win[ i]); |
| out[i+12] += history[i+12]; |
| history[12+i] = 0; |
| } |
| } |
| |
| break; |
| } |
| |
| /* |
| * Compensation for frequency inversion of polyphase filterbank |
| * every odd time sample of every odd odd subband is mulitplied by -1 before |
| * processing by the polyphase filter |
| */ |
| |
| if (band & 1) |
| { |
| for (int32 slot = 1; slot < FILTERBANK_BANDS; slot += 6) |
| { |
| int32 temp1 = out[slot ]; |
| int32 temp2 = out[slot+2]; |
| int32 temp3 = out[slot+4]; |
| out[slot ] = -temp1; |
| out[slot+2] = -temp2; |
| out[slot+4] = -temp3; |
| } |
| } |
| } |
| |
| |
| for (band = bands2process; band < SUBBANDS_NUMBER; band++) |
| { |
| int32 * out = in + (band * FILTERBANK_BANDS); |
| int32 * history = overlap + (band * FILTERBANK_BANDS); |
| int32 slot; |
| |
| if (band & 1) |
| { |
| for (slot = 0; slot < FILTERBANK_BANDS; slot += 6) |
| { |
| int32 temp1 = history[slot ]; |
| int32 temp2 = history[slot+1]; |
| int32 temp3 = history[slot+2]; |
| out[slot ] = temp1; |
| out[slot+1] = -temp2; |
| out[slot+2] = temp3; |
| |
| temp1 = history[slot+3]; |
| temp2 = history[slot+4]; |
| temp3 = history[slot+5]; |
| out[slot+3] = -temp1; |
| out[slot+4] = temp2; |
| out[slot+5] = -temp3; |
| } |
| } |
| else |
| { |
| for (slot = 0; slot < FILTERBANK_BANDS; slot += 3) |
| { |
| int32 temp1 = history[slot ]; |
| int32 temp2 = history[slot+1]; |
| int32 temp3 = history[slot+2]; |
| out[slot ] = temp1; |
| out[slot+1] = temp2; |
| out[slot+2] = temp3; |
| } |
| } |
| |
| pv_memset(history, 0, FILTERBANK_BANDS*sizeof(*overlap)); |
| } |
| } |
| |
| |
| |
| |
