159 lines
6.5 KiB
C
159 lines
6.5 KiB
C
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/* ***** BEGIN LICENSE BLOCK *****
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* Version: RCSL 1.0/RPSL 1.0
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*
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* Portions Copyright (c) 1995-2002 RealNetworks, Inc. All Rights Reserved.
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*
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* The contents of this file, and the files included with this file, are
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* subject to the current version of the RealNetworks Public Source License
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* Version 1.0 (the "RPSL") available at
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* http://www.helixcommunity.org/content/rpsl unless you have licensed
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* the file under the RealNetworks Community Source License Version 1.0
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* (the "RCSL") available at http://www.helixcommunity.org/content/rcsl,
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* in which case the RCSL will apply. You may also obtain the license terms
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* directly from RealNetworks. You may not use this file except in
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* compliance with the RPSL or, if you have a valid RCSL with RealNetworks
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* applicable to this file, the RCSL. Please see the applicable RPSL or
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* RCSL for the rights, obligations and limitations governing use of the
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* contents of the file.
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*
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* This file is part of the Helix DNA Technology. RealNetworks is the
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* developer of the Original Code and owns the copyrights in the portions
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* it created.
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*
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* This file, and the files included with this file, is distributed and made
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* available on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
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* EXPRESS OR IMPLIED, AND REALNETWORKS HEREBY DISCLAIMS ALL SUCH WARRANTIES,
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* INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, FITNESS
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* FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
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*
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* Technology Compatibility Kit Test Suite(s) Location:
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* http://www.helixcommunity.org/content/tck
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*
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* Contributor(s):
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*
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* ***** END LICENSE BLOCK ***** */
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/**************************************************************************************
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* Fixed-point MP3 decoder
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* Jon Recker (jrecker@real.com), Ken Cooke (kenc@real.com)
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* June 2003
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*
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* dequant.c - dequantization, stereo processing (intensity, mid-side), short-block
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* coefficient reordering
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**************************************************************************************/
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#include "coder.h"
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#include "assembly.h"
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/**************************************************************************************
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* Function: Dequantize
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*
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* Description: dequantize coefficients, decode stereo, reorder short blocks
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* (one granule-worth)
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*
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* Inputs: MP3DecInfo structure filled by UnpackFrameHeader(), UnpackSideInfo(),
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* UnpackScaleFactors(), and DecodeHuffman() (for this granule)
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* index of current granule
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*
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* Outputs: dequantized and reordered coefficients in hi->huffDecBuf
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* (one granule-worth, all channels), format = Q26
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* operates in-place on huffDecBuf but also needs di->workBuf
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* updated hi->nonZeroBound index for both channels
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*
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* Return: 0 on success, -1 if null input pointers
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*
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* Notes: In calling output Q(DQ_FRACBITS_OUT), we assume an implicit bias
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* of 2^15. Some (floating-point) reference implementations factor this
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* into the 2^(0.25 * gain) scaling explicitly. But to avoid precision
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* loss, we don't do that. Instead take it into account in the final
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* round to PCM (>> by 15 less than we otherwise would have).
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* Equivalently, we can think of the dequantized coefficients as
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* Q(DQ_FRACBITS_OUT - 15) with no implicit bias.
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**************************************************************************************/
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int Dequantize(MP3DecInfo *mp3DecInfo, int gr)
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{
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int i, ch, nSamps, mOut[2];
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FrameHeader *fh;
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SideInfo *si;
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ScaleFactorInfo *sfi;
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HuffmanInfo *hi;
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DequantInfo *di;
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CriticalBandInfo *cbi;
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/* validate pointers */
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if (!mp3DecInfo || !mp3DecInfo->FrameHeaderPS || !mp3DecInfo->SideInfoPS || !mp3DecInfo->ScaleFactorInfoPS ||
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!mp3DecInfo->HuffmanInfoPS || !mp3DecInfo->DequantInfoPS)
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return -1;
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fh = (FrameHeader *)(mp3DecInfo->FrameHeaderPS);
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/* si is an array of up to 4 structs, stored as gr0ch0, gr0ch1, gr1ch0, gr1ch1 */
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si = (SideInfo *)(mp3DecInfo->SideInfoPS);
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sfi = (ScaleFactorInfo *)(mp3DecInfo->ScaleFactorInfoPS);
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hi = (HuffmanInfo *)mp3DecInfo->HuffmanInfoPS;
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di = (DequantInfo *)mp3DecInfo->DequantInfoPS;
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cbi = di->cbi;
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mOut[0] = mOut[1] = 0;
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/* dequantize all the samples in each channel */
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for (ch = 0; ch < mp3DecInfo->nChans; ch++) {
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hi->gb[ch] = DequantChannel(hi->huffDecBuf[ch], di->workBuf, &hi->nonZeroBound[ch], fh,
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&si->sis[gr][ch], &sfi->sfis[gr][ch], &cbi[ch]);
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}
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/* joint stereo processing assumes one guard bit in input samples
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* it's extremely rare not to have at least one gb, so if this is the case
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* just make a pass over the data and clip to [-2^30+1, 2^30-1]
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* in practice this may never happen
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*/
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if (fh->modeExt && (hi->gb[0] < 1 || hi->gb[1] < 1)) {
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for (i = 0; i < hi->nonZeroBound[0]; i++) {
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if (hi->huffDecBuf[0][i] < -0x3fffffff) hi->huffDecBuf[0][i] = -0x3fffffff;
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if (hi->huffDecBuf[0][i] > 0x3fffffff) hi->huffDecBuf[0][i] = 0x3fffffff;
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}
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for (i = 0; i < hi->nonZeroBound[1]; i++) {
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if (hi->huffDecBuf[1][i] < -0x3fffffff) hi->huffDecBuf[1][i] = -0x3fffffff;
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if (hi->huffDecBuf[1][i] > 0x3fffffff) hi->huffDecBuf[1][i] = 0x3fffffff;
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}
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}
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/* do mid-side stereo processing, if enabled */
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if (fh->modeExt >> 1) {
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if (fh->modeExt & 0x01) {
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/* intensity stereo enabled - run mid-side up to start of right zero region */
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if (cbi[1].cbType == 0)
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nSamps = fh->sfBand->l[cbi[1].cbEndL + 1];
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else
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nSamps = 3 * fh->sfBand->s[cbi[1].cbEndSMax + 1];
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} else {
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/* intensity stereo disabled - run mid-side on whole spectrum */
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nSamps = MAX(hi->nonZeroBound[0], hi->nonZeroBound[1]);
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}
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MidSideProc(hi->huffDecBuf, nSamps, mOut);
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}
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/* do intensity stereo processing, if enabled */
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if (fh->modeExt & 0x01) {
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nSamps = hi->nonZeroBound[0];
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if (fh->ver == MPEG1) {
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IntensityProcMPEG1(hi->huffDecBuf, nSamps, fh, &sfi->sfis[gr][1], di->cbi,
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fh->modeExt >> 1, si->sis[gr][1].mixedBlock, mOut);
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} else {
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IntensityProcMPEG2(hi->huffDecBuf, nSamps, fh, &sfi->sfis[gr][1], di->cbi, &sfi->sfjs,
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fh->modeExt >> 1, si->sis[gr][1].mixedBlock, mOut);
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}
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}
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/* adjust guard bit count and nonZeroBound if we did any stereo processing */
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if (fh->modeExt) {
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hi->gb[0] = CLZ(mOut[0]) - 1;
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hi->gb[1] = CLZ(mOut[1]) - 1;
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nSamps = MAX(hi->nonZeroBound[0], hi->nonZeroBound[1]);
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hi->nonZeroBound[0] = nSamps;
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hi->nonZeroBound[1] = nSamps;
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}
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/* output format Q(DQ_FRACBITS_OUT) */
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return 0;
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}
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