diff options
Diffstat (limited to 'media/libstagefright/codecs/aacenc/src/block_switch.c')
| -rw-r--r-- | media/libstagefright/codecs/aacenc/src/block_switch.c | 431 |
1 files changed, 431 insertions, 0 deletions
diff --git a/media/libstagefright/codecs/aacenc/src/block_switch.c b/media/libstagefright/codecs/aacenc/src/block_switch.c new file mode 100644 index 0000000..c0054f7 --- /dev/null +++ b/media/libstagefright/codecs/aacenc/src/block_switch.c @@ -0,0 +1,431 @@ +/*
+ ** Copyright 2003-2010, VisualOn, Inc.
+ **
+ ** 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.
+ */
+/*******************************************************************************
+ File: block_switch.c
+
+ Content: Block switching functions
+
+*******************************************************************************/ + +#include "typedef.h"
+#include "basic_op.h"
+#include "oper_32b.h" +#include "psy_const.h" +#include "block_switch.h" + + +#define ENERGY_SHIFT (8 - 1) + +/**************** internal function prototypes ***********/ +static Word16 +IIRFilter(const Word16 in, const Word32 coeff[], Word32 states[]); + +static Word32 +SrchMaxWithIndex(const Word32 *in, Word16 *index, Word16 n); + + +Word32 +CalcWindowEnergy(BLOCK_SWITCHING_CONTROL *blockSwitchingControl, + Word16 *timeSignal, + Word16 chIncrement, + Word16 windowLen); + + + +/****************** Constants *****************************/ + + +/* + IIR high pass coeffs +*/ +Word32 hiPassCoeff[BLOCK_SWITCHING_IIR_LEN] = { + 0xbec8b439, 0x609d4952 /* -0.5095f, 0.7548f */ +}; + +static const Word32 accWindowNrgFac = 0x26666666; /* factor for accumulating filtered window energies 0.3 */ +static const Word32 oneMinusAccWindowNrgFac = 0x5999999a; /* 0.7 */ +static const Word32 invAttackRatioHighBr = 0x0ccccccd; /* inverted lower ratio limit for attacks 0.1*/ +static const Word32 invAttackRatioLowBr = 0x072b020c; /* 0.056 */ +static const Word32 minAttackNrg = 0x00001e84; /* minimum energy for attacks 1e+6 */ + + +/****************** Routines ****************************/ + + +/***************************************************************************** +* +* function name: InitBlockSwitching +* description: init Block Switching parameter. +* returns: TRUE if success +* +**********************************************************************************/ +Word16 InitBlockSwitching(BLOCK_SWITCHING_CONTROL *blockSwitchingControl, + const Word32 bitRate, const Word16 nChannels) +{ + /* select attackRatio */ + + if ((sub(nChannels,1)==0 && L_sub(bitRate, 24000) > 0) || + (sub(nChannels,1)>0 && bitRate > (nChannels * 16000))) { + blockSwitchingControl->invAttackRatio = invAttackRatioHighBr; + } + else { + blockSwitchingControl->invAttackRatio = invAttackRatioLowBr; + } + + return(TRUE); +} + +static Word16 suggestedGroupingTable[TRANS_FAC][MAX_NO_OF_GROUPS] = { + /* Attack in Window 0 */ {1, 3, 3, 1}, + /* Attack in Window 1 */ {1, 1, 3, 3}, + /* Attack in Window 2 */ {2, 1, 3, 2}, + /* Attack in Window 3 */ {3, 1, 3, 1}, + /* Attack in Window 4 */ {3, 1, 1, 3}, + /* Attack in Window 5 */ {3, 2, 1, 2}, + /* Attack in Window 6 */ {3, 3, 1, 1}, + /* Attack in Window 7 */ {3, 3, 1, 1} +}; + +/***************************************************************************** +* +* function name: BlockSwitching +* description: detect this frame whether there is an attack +* returns: TRUE if success +* +**********************************************************************************/ +Word16 BlockSwitching(BLOCK_SWITCHING_CONTROL *blockSwitchingControl, + Word16 *timeSignal, + Word32 sampleRate, + Word16 chIncrement) +{ + Word32 i, w; + Word32 enM1, enMax; + + /* Reset grouping info */ + for (i=0; i<TRANS_FAC; i++) { + blockSwitchingControl->groupLen[i] = 0; + } + + + /* Search for position and amplitude of attack in last frame (1 windows delay) */ + blockSwitchingControl->maxWindowNrg = SrchMaxWithIndex( &blockSwitchingControl->windowNrg[0][BLOCK_SWITCH_WINDOWS-1], + &blockSwitchingControl->attackIndex, + BLOCK_SWITCH_WINDOWS); + + blockSwitchingControl->attackIndex = blockSwitchingControl->lastAttackIndex; + + /* Set grouping info */ + blockSwitchingControl->noOfGroups = MAX_NO_OF_GROUPS; + + for (i=0; i<MAX_NO_OF_GROUPS; i++) { + blockSwitchingControl->groupLen[i] = suggestedGroupingTable[blockSwitchingControl->attackIndex][i]; + }
+ + /* if the samplerate is less than 16000, it should be all the short block, avoid pre&post echo */ + if(sampleRate >= 16000) { + /* Save current window energy as last window energy */ + for (w=0; w<BLOCK_SWITCH_WINDOWS; w++) { + blockSwitchingControl->windowNrg[0][w] = blockSwitchingControl->windowNrg[1][w]; + blockSwitchingControl->windowNrgF[0][w] = blockSwitchingControl->windowNrgF[1][w]; + } + + + /* Calculate unfiltered and filtered energies in subwindows and combine to segments */ + CalcWindowEnergy(blockSwitchingControl, timeSignal, chIncrement, BLOCK_SWITCH_WINDOW_LEN); + + /* reset attack */ + blockSwitchingControl->attack = FALSE; + + enMax = 0; + enM1 = blockSwitchingControl->windowNrgF[0][BLOCK_SWITCH_WINDOWS-1]; + + for (w=0; w<BLOCK_SWITCH_WINDOWS; w++) { + Word32 enM1_Tmp, accWindowNrg_Tmp, windowNrgF_Tmp; + Word16 enM1_Shf, accWindowNrg_Shf, windowNrgF_Shf; + + accWindowNrg_Shf = norm_l(blockSwitchingControl->accWindowNrg); + enM1_Shf = norm_l(enM1); + windowNrgF_Shf = norm_l(blockSwitchingControl->windowNrgF[1][w]); + + accWindowNrg_Tmp = blockSwitchingControl->accWindowNrg << accWindowNrg_Shf; + enM1_Tmp = enM1 << enM1_Shf; + windowNrgF_Tmp = blockSwitchingControl->windowNrgF[1][w] << windowNrgF_Shf; + + /* a sliding average of the previous energies */ + blockSwitchingControl->accWindowNrg = (fixmul(oneMinusAccWindowNrgFac, accWindowNrg_Tmp) >> accWindowNrg_Shf) + + (fixmul(accWindowNrgFac, enM1_Tmp) >> enM1_Shf); + + + /* if the energy with the ratio is bigger than the average, and the attack and short block */ + if ((fixmul(windowNrgF_Tmp, blockSwitchingControl->invAttackRatio) >> windowNrgF_Shf) > + blockSwitchingControl->accWindowNrg ) { + blockSwitchingControl->attack = TRUE; + blockSwitchingControl->lastAttackIndex = w; + } + enM1 = blockSwitchingControl->windowNrgF[1][w]; + enMax = max(enMax, enM1); + } + + if (enMax < minAttackNrg) { + blockSwitchingControl->attack = FALSE; + } + } + else + { + blockSwitchingControl->attack = TRUE; + } + + /* Check if attack spreads over frame border */ + if ((!blockSwitchingControl->attack) && (blockSwitchingControl->lastattack)) { + + if (blockSwitchingControl->attackIndex == TRANS_FAC-1) { + blockSwitchingControl->attack = TRUE; + } + + blockSwitchingControl->lastattack = FALSE; + } + else { + blockSwitchingControl->lastattack = blockSwitchingControl->attack; + } + + blockSwitchingControl->windowSequence = blockSwitchingControl->nextwindowSequence; + + + if (blockSwitchingControl->attack) { + blockSwitchingControl->nextwindowSequence = SHORT_WINDOW; + } + else { + blockSwitchingControl->nextwindowSequence = LONG_WINDOW; + } + + /* update short block group */ + if (blockSwitchingControl->nextwindowSequence == SHORT_WINDOW) { + + if (blockSwitchingControl->windowSequence== LONG_WINDOW) { + blockSwitchingControl->windowSequence = START_WINDOW; + } + + if (blockSwitchingControl->windowSequence == STOP_WINDOW) { + blockSwitchingControl->windowSequence = SHORT_WINDOW; + blockSwitchingControl->noOfGroups = 3; + blockSwitchingControl->groupLen[0] = 3; + blockSwitchingControl->groupLen[1] = 3; + blockSwitchingControl->groupLen[2] = 2; + } + } + + /* update block type */ + if (blockSwitchingControl->nextwindowSequence == LONG_WINDOW) { + + if (blockSwitchingControl->windowSequence == SHORT_WINDOW) { + blockSwitchingControl->nextwindowSequence = STOP_WINDOW; + } + } + + return(TRUE); +} + + +/***************************************************************************** +* +* function name: SrchMaxWithIndex +* description: search for the biggest value in an array +* returns: the max value +* +**********************************************************************************/ +static Word32 SrchMaxWithIndex(const Word32 in[], Word16 *index, Word16 n) +{ + Word32 max; + Word32 i, idx; + + /* Search maximum value in array and return index and value */ + max = 0; + idx = 0; + + for (i = 0; i < n; i++) { + + if (in[i+1] > max) { + max = in[i+1]; + idx = i; + } + } + *index = idx; + + return(max); +} + +/***************************************************************************** +* +* function name: CalcWindowEnergy +* description: calculate the energy before iir-filter and after irr-filter +* returns: TRUE if success +* +**********************************************************************************/ +#ifndef ARMV5E
+Word32 CalcWindowEnergy(BLOCK_SWITCHING_CONTROL *blockSwitchingControl, + Word16 *timeSignal, + Word16 chIncrement, + Word16 windowLen) +{ + Word32 w, i, wOffset, tidx, ch; + Word32 accuUE, accuFE; + Word32 tempUnfiltered; + Word32 tempFiltered;
+ Word32 states0, states1;
+ Word32 Coeff0, Coeff1;
+
+ + states0 = blockSwitchingControl->iirStates[0];
+ states1 = blockSwitchingControl->iirStates[1];
+ Coeff0 = hiPassCoeff[0];
+ Coeff1 = hiPassCoeff[1]; + tidx = 0; + for (w=0; w < BLOCK_SWITCH_WINDOWS; w++) { + + accuUE = 0; + accuFE = 0; + + for(i=0; i<windowLen; i++) { + Word32 accu1, accu2, accu3;
+ Word32 out;
+ tempUnfiltered = timeSignal[tidx]; + tidx = tidx + chIncrement; +
+ accu1 = L_mpy_ls(Coeff1, tempUnfiltered);
+ accu2 = fixmul( Coeff0, states1 );
+ accu3 = accu1 - states0;
+ out = accu3 - accu2;
+
+ states0 = accu1;
+ states1 = out;
+
+ tempFiltered = extract_h(out); + accuUE += (tempUnfiltered * tempUnfiltered) >> ENERGY_SHIFT; + accuFE += (tempFiltered * tempFiltered) >> ENERGY_SHIFT; + } + + blockSwitchingControl->windowNrg[1][w] = accuUE; + blockSwitchingControl->windowNrgF[1][w] = accuFE; + + }
+
+ blockSwitchingControl->iirStates[0] = states0;
+ blockSwitchingControl->iirStates[1] = states1; + + return(TRUE); +} +#endif + +/***************************************************************************** +* +* function name: IIRFilter +* description: calculate the iir-filter for an array +* returns: the result after iir-filter +* +**********************************************************************************/ +static Word16 IIRFilter(const Word16 in, const Word32 coeff[], Word32 states[]) +{ + Word32 accu1, accu2, accu3; + Word32 out; + + accu1 = L_mpy_ls(coeff[1], in); + accu3 = accu1 - states[0]; + accu2 = fixmul( coeff[0], states[1] ); + out = accu3 - accu2; + + states[0] = accu1; + states[1] = out; + + return round16(out); +} + + +static Word16 synchronizedBlockTypeTable[4][4] = { + /* LONG_WINDOW START_WINDOW SHORT_WINDOW STOP_WINDOW */ + /* LONG_WINDOW */{LONG_WINDOW, START_WINDOW, SHORT_WINDOW, STOP_WINDOW}, + /* START_WINDOW */{START_WINDOW, START_WINDOW, SHORT_WINDOW, SHORT_WINDOW}, + /* SHORT_WINDOW */{SHORT_WINDOW, SHORT_WINDOW, SHORT_WINDOW, SHORT_WINDOW}, + /* STOP_WINDOW */{STOP_WINDOW, SHORT_WINDOW, SHORT_WINDOW, STOP_WINDOW} +}; + + +/***************************************************************************** +* +* function name: SyncBlockSwitching +* description: update block type and group value +* returns: TRUE if success +* +**********************************************************************************/ +Word16 SyncBlockSwitching(BLOCK_SWITCHING_CONTROL *blockSwitchingControlLeft, + BLOCK_SWITCHING_CONTROL *blockSwitchingControlRight, + const Word16 nChannels) +{ + Word16 i; + Word16 patchType = LONG_WINDOW; + + + if (nChannels == 1) { /* Mono */ + if (blockSwitchingControlLeft->windowSequence != SHORT_WINDOW) { + blockSwitchingControlLeft->noOfGroups = 1; + blockSwitchingControlLeft->groupLen[0] = 1; + + for (i=1; i<TRANS_FAC; i++) { + blockSwitchingControlLeft->groupLen[i] = 0; + } + } + } + else { /* Stereo common Window */ + patchType = synchronizedBlockTypeTable[patchType][blockSwitchingControlLeft->windowSequence]; + patchType = synchronizedBlockTypeTable[patchType][blockSwitchingControlRight->windowSequence]; + + /* Set synchronized Blocktype */ + blockSwitchingControlLeft->windowSequence = patchType; + blockSwitchingControlRight->windowSequence = patchType; + + /* Synchronize grouping info */ + if(patchType != SHORT_WINDOW) { /* Long Blocks */ + /* Set grouping info */ + blockSwitchingControlLeft->noOfGroups = 1; + blockSwitchingControlRight->noOfGroups = 1; + blockSwitchingControlLeft->groupLen[0] = 1; + blockSwitchingControlRight->groupLen[0] = 1; + + for (i=1; i<TRANS_FAC; i++) { + blockSwitchingControlLeft->groupLen[i] = 0; + blockSwitchingControlRight->groupLen[i] = 0; + } + } + else { + + if (blockSwitchingControlLeft->maxWindowNrg > blockSwitchingControlRight->maxWindowNrg) { + /* Left Channel wins */ + blockSwitchingControlRight->noOfGroups = blockSwitchingControlLeft->noOfGroups; + for (i=0; i<TRANS_FAC; i++) { + blockSwitchingControlRight->groupLen[i] = blockSwitchingControlLeft->groupLen[i]; + } + } + else { + /* Right Channel wins */ + blockSwitchingControlLeft->noOfGroups = blockSwitchingControlRight->noOfGroups; + for (i=0; i<TRANS_FAC; i++) { + blockSwitchingControlLeft->groupLen[i] = blockSwitchingControlRight->groupLen[i]; + } + } + } + } /*endif Mono or Stereo */ + + return(TRUE); +} |