227 lines
7.0 KiB
C++
227 lines
7.0 KiB
C++
/* ------------------------------------------------------------------
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* Copyright (C) 1998-2009 PacketVideo
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either
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* express or implied.
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* See the License for the specific language governing permissions
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* and limitations under the License.
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* -------------------------------------------------------------------
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*/
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/*
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------------------------------------------------------------------------------
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PacketVideo Corp.
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MP3 Decoder Library
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Filename: pvmp3_get_scale_factors.cpp
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Date: 09/21/2007
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------------------------------------------------------------------------------
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REVISION HISTORY
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Description:
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------------------------------------------------------------------------------
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INPUT AND OUTPUT DEFINITIONS
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Input
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mp3ScaleFactors *scalefac,
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mp3SideInfo *si, side info
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int32 gr, granule
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int32 ch, channel
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tbits *pMainData bit stream
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Returns
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mp3ScaleFactors *scalefac, scale factors
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------------------------------------------------------------------------------
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FUNCTION DESCRIPTION
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get scale factors
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------------------------------------------------------------------------------
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REQUIREMENTS
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------------------------------------------------------------------------------
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REFERENCES
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[1] ISO MPEG Audio Subgroup Software Simulation Group (1996)
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ISO 13818-3 MPEG-2 Audio Decoder - Lower Sampling Frequency Extension
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------------------------------------------------------------------------------
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PSEUDO-CODE
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------------------------------------------------------------------------------
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*/
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/*----------------------------------------------------------------------------
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; INCLUDES
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----------------------------------------------------------------------------*/
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#include "pvmp3_get_scale_factors.h"
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#include "pvmp3_getbits.h"
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#include "mp3_mem_funcs.h"
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/*----------------------------------------------------------------------------
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; MACROS
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; Define module specific macros here
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----------------------------------------------------------------------------*/
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/*----------------------------------------------------------------------------
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; DEFINES
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; Include all pre-processor statements here. Include conditional
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; compile variables also.
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----------------------------------------------------------------------------*/
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#define Qfmt_28(a)(int32(double(0x10000000)*a))
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/*----------------------------------------------------------------------------
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; LOCAL FUNCTION DEFINITIONS
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; Function Prototype declaration
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----------------------------------------------------------------------------*/
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/*----------------------------------------------------------------------------
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; LOCAL STORE/BUFFER/POINTER DEFINITIONS
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; Variable declaration - defined here and used outside this module
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----------------------------------------------------------------------------*/
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const int32 slen[2][16] =
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{
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{0, 0, 0, 0, 3, 1, 1, 1, 2, 2, 2, 3, 3, 3, 4, 4},
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{0, 1, 2, 3, 0, 1, 2, 3, 1, 2, 3, 1, 2, 3, 2, 3}
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};
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const struct
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{
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int32 l[5];
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int32 s[3];
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} sfbtable =
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{
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{0, 6, 11, 16, 21},
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{0, 6, 12}
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};
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const int32 long_sfbtable[4] = { 6, 5, 5, 5};
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/*----------------------------------------------------------------------------
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; EXTERNAL FUNCTION REFERENCES
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; Declare functions defined elsewhere and referenced in this module
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----------------------------------------------------------------------------*/
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/*----------------------------------------------------------------------------
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; EXTERNAL GLOBAL STORE/BUFFER/POINTER REFERENCES
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; Declare variables used in this module but defined elsewhere
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----------------------------------------------------------------------------*/
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/*----------------------------------------------------------------------------
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; FUNCTION CODE
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----------------------------------------------------------------------------*/
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void pvmp3_get_scale_factors(mp3ScaleFactors *scalefac,
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mp3SideInfo *si,
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int32 gr,
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int32 ch,
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tmp3Bits *pMainData)
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{
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int32 sfb;
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int32 i;
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int32 window;
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granuleInfo *gr_info = &(si->ch[ch].gran[gr]);
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if (gr_info->window_switching_flag && (gr_info->block_type == 2))
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{
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if (gr_info->mixed_block_flag)
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{ /* MIXED */
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for (sfb = 0; sfb < 8; sfb++)
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{
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scalefac->l[sfb] = getNbits(pMainData, slen[0][gr_info->scalefac_compress]);
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}
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for (sfb = 3; sfb < 6; sfb++)
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{
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for (window = 0; window < 3; window++)
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{
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scalefac->s[window][sfb] = getNbits(pMainData, slen[0][gr_info->scalefac_compress]);
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}
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}
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for (sfb = 6; sfb < 12; sfb++)
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{
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for (window = 0; window < 3; window++)
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{
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scalefac->s[window][sfb] = getNbits(pMainData, slen[1][gr_info->scalefac_compress]);
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}
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}
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}
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else
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{ /* SHORT*/
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for (i = 0; i < 2; i++)
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{
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for (sfb = sfbtable.s[i]; sfb < sfbtable.s[i+1]; sfb++)
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{
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for (window = 0; window < 3; window++)
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{
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scalefac->s[window][sfb] = getNbits(pMainData, slen[i][gr_info->scalefac_compress]);
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}
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}
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}
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}
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scalefac->s[0][12] = 0; /* sfb = 12 win= 0 */
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scalefac->s[1][12] = 0; /* sfb = 12 win= 1 */
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scalefac->s[2][12] = 0; /* sfb = 12 win= 2 */
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}
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else
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{ /* LONG types 0,1,3 */
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int32 *ptr = &scalefac->l[0];
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for (i = 0; i < 4; i++)
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{
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int32 tmp4 = long_sfbtable[i];
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if ((si->ch[ch].scfsi[i] == 0) || (gr == 0))
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{
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int32 tmp1 = slen[(i>>1)][gr_info->scalefac_compress];
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if (tmp1)
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{
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int32 tmp2 = tmp1 * tmp4;
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uint32 tmp3 = getNbits(pMainData, tmp2);
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tmp4 = 32 - tmp1;
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for (; tmp2 > 0; tmp2 -= tmp1)
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{
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*(ptr++) = (tmp3 << (32 - tmp2)) >> tmp4;
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}
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}
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else
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{
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for (sfb = tmp4; sfb != 0; sfb--)
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{
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*(ptr++) = 0;
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}
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}
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}
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else
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{
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ptr += tmp4;
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}
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}
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scalefac->l[21] = 0;
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scalefac->l[22] = 0;
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}
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}
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