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Diffstat (limited to 'circuitpython/lib/mp3/src/scalfact.c')
| -rw-r--r-- | circuitpython/lib/mp3/src/scalfact.c | 388 |
1 files changed, 388 insertions, 0 deletions
diff --git a/circuitpython/lib/mp3/src/scalfact.c b/circuitpython/lib/mp3/src/scalfact.c new file mode 100644 index 0000000..85974ff --- /dev/null +++ b/circuitpython/lib/mp3/src/scalfact.c @@ -0,0 +1,388 @@ +/* ***** BEGIN LICENSE BLOCK ***** + * Version: RCSL 1.0/RPSL 1.0 + * + * Portions Copyright (c) 1995-2002 RealNetworks, Inc. All Rights Reserved. + * + * The contents of this file, and the files included with this file, are + * subject to the current version of the RealNetworks Public Source License + * Version 1.0 (the "RPSL") available at + * http://www.helixcommunity.org/content/rpsl unless you have licensed + * the file under the RealNetworks Community Source License Version 1.0 + * (the "RCSL") available at http://www.helixcommunity.org/content/rcsl, + * in which case the RCSL will apply. You may also obtain the license terms + * directly from RealNetworks. You may not use this file except in + * compliance with the RPSL or, if you have a valid RCSL with RealNetworks + * applicable to this file, the RCSL. Please see the applicable RPSL or + * RCSL for the rights, obligations and limitations governing use of the + * contents of the file. + * + * This file is part of the Helix DNA Technology. RealNetworks is the + * developer of the Original Code and owns the copyrights in the portions + * it created. + * + * This file, and the files included with this file, is distributed and made + * available on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER + * EXPRESS OR IMPLIED, AND REALNETWORKS HEREBY DISCLAIMS ALL SUCH WARRANTIES, + * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, FITNESS + * FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT. + * + * Technology Compatibility Kit Test Suite(s) Location: + * http://www.helixcommunity.org/content/tck + * + * Contributor(s): + * + * ***** END LICENSE BLOCK ***** */ + +/************************************************************************************** + * Fixed-point MP3 decoder + * Jon Recker (jrecker@real.com), Ken Cooke (kenc@real.com) + * June 2003 + * + * scalfact.c - scalefactor unpacking functions + **************************************************************************************/ + +#include "coder.h" + +/* scale factor lengths (num bits) */ +static const char SFLenTab[16][2] = { + {0, 0}, {0, 1}, + {0, 2}, {0, 3}, + {3, 0}, {1, 1}, + {1, 2}, {1, 3}, + {2, 1}, {2, 2}, + {2, 3}, {3, 1}, + {3, 2}, {3, 3}, + {4, 2}, {4, 3}, +}; + +/************************************************************************************** + * Function: UnpackSFMPEG1 + * + * Description: unpack MPEG 1 scalefactors from bitstream + * + * Inputs: BitStreamInfo, SideInfoSub, ScaleFactorInfoSub structs for this + * granule/channel + * vector of scfsi flags from side info, length = 4 (MAX_SCFBD) + * index of current granule + * ScaleFactorInfoSub from granule 0 (for granule 1, if scfsi[i] is set, + * then we just replicate the scale factors from granule 0 in the + * i'th set of scalefactor bands) + * + * Outputs: updated BitStreamInfo struct + * scalefactors in sfis (short and/or long arrays, as appropriate) + * + * Return: none + * + * Notes: set order of short blocks to s[band][window] instead of s[window][band] + * so that we index through consectutive memory locations when unpacking + * (make sure dequantizer follows same convention) + * Illegal Intensity Position = 7 (always) for MPEG1 scale factors + **************************************************************************************/ +static void UnpackSFMPEG1(BitStreamInfo *bsi, SideInfoSub *sis, ScaleFactorInfoSub *sfis, int *scfsi, int gr, ScaleFactorInfoSub *sfisGr0) +{ + int sfb; + int slen0, slen1; + + /* these can be 0, so make sure GetBits(bsi, 0) returns 0 (no >> 32 or anything) */ + slen0 = (int)SFLenTab[sis->sfCompress][0]; + slen1 = (int)SFLenTab[sis->sfCompress][1]; + + if (sis->blockType == 2) { + /* short block, type 2 (implies winSwitchFlag == 1) */ + if (sis->mixedBlock) { + /* do long block portion */ + for (sfb = 0; sfb < 8; sfb++) + sfis->l[sfb] = (char)GetBits(bsi, slen0); + sfb = 3; + } else { + /* all short blocks */ + sfb = 0; + } + + for ( ; sfb < 6; sfb++) { + sfis->s[sfb][0] = (char)GetBits(bsi, slen0); + sfis->s[sfb][1] = (char)GetBits(bsi, slen0); + sfis->s[sfb][2] = (char)GetBits(bsi, slen0); + } + + for ( ; sfb < 12; sfb++) { + sfis->s[sfb][0] = (char)GetBits(bsi, slen1); + sfis->s[sfb][1] = (char)GetBits(bsi, slen1); + sfis->s[sfb][2] = (char)GetBits(bsi, slen1); + } + + /* last sf band not transmitted */ + sfis->s[12][0] = sfis->s[12][1] = sfis->s[12][2] = 0; + } else { + /* long blocks, type 0, 1, or 3 */ + if(gr == 0) { + /* first granule */ + for (sfb = 0; sfb < 11; sfb++) + sfis->l[sfb] = (char)GetBits(bsi, slen0); + for (sfb = 11; sfb < 21; sfb++) + sfis->l[sfb] = (char)GetBits(bsi, slen1); + return; + } else { + /* second granule + * scfsi: 0 = different scalefactors for each granule, 1 = copy sf's from granule 0 into granule 1 + * for block type == 2, scfsi is always 0 + */ + sfb = 0; + if(scfsi[0]) for( ; sfb < 6 ; sfb++) sfis->l[sfb] = sfisGr0->l[sfb]; + else for( ; sfb < 6 ; sfb++) sfis->l[sfb] = (char)GetBits(bsi, slen0); + if(scfsi[1]) for( ; sfb <11 ; sfb++) sfis->l[sfb] = sfisGr0->l[sfb]; + else for( ; sfb <11 ; sfb++) sfis->l[sfb] = (char)GetBits(bsi, slen0); + if(scfsi[2]) for( ; sfb <16 ; sfb++) sfis->l[sfb] = sfisGr0->l[sfb]; + else for( ; sfb <16 ; sfb++) sfis->l[sfb] = (char)GetBits(bsi, slen1); + if(scfsi[3]) for( ; sfb <21 ; sfb++) sfis->l[sfb] = sfisGr0->l[sfb]; + else for( ; sfb <21 ; sfb++) sfis->l[sfb] = (char)GetBits(bsi, slen1); + } + /* last sf band not transmitted */ + sfis->l[21] = 0; + sfis->l[22] = 0; + } +} + +/* NRTab[size + 3*is_right][block type][partition] + * block type index: 0 = (bt0,bt1,bt3), 1 = bt2 non-mixed, 2 = bt2 mixed + * partition: scale factor groups (sfb1 through sfb4) + * for block type = 2 (mixed or non-mixed) / by 3 is rolled into this table + * (for 3 short blocks per long block) + * see 2.4.3.2 in MPEG 2 (low sample rate) spec + * stuff rolled into this table: + * NRTab[x][1][y] --> (NRTab[x][1][y]) / 3 + * NRTab[x][2][>=1] --> (NRTab[x][2][>=1]) / 3 (first partition is long block) + */ +static const char NRTab[6][3][4] = { + /* non-intensity stereo */ + { {6, 5, 5, 5}, + {3, 3, 3, 3}, /* includes / 3 */ + {6, 3, 3, 3}, /* includes / 3 except for first entry */ + }, + { {6, 5, 7, 3}, + {3, 3, 4, 2}, + {6, 3, 4, 2}, + }, + { {11, 10, 0, 0}, + {6, 6, 0, 0}, + {6, 3, 6, 0}, /* spec = [15,18,0,0], but 15 = 6L + 9S, so move 9/3=3 into col 1, 18/3=6 into col 2 and adj. slen[1,2] below */ + }, + /* intensity stereo, right chan */ + { {7, 7, 7, 0}, + {4, 4, 4, 0}, + {6, 5, 4, 0}, + }, + { {6, 6, 6, 3}, + {4, 3, 3, 2}, + {6, 4, 3, 2}, + }, + { {8, 8, 5, 0}, + {5, 4, 3, 0}, + {6, 6, 3, 0}, + } +}; + +/************************************************************************************** + * Function: UnpackSFMPEG2 + * + * Description: unpack MPEG 2 scalefactors from bitstream + * + * Inputs: BitStreamInfo, SideInfoSub, ScaleFactorInfoSub structs for this + * granule/channel + * index of current granule and channel + * ScaleFactorInfoSub from this granule + * modeExt field from frame header, to tell whether intensity stereo is on + * ScaleFactorJS struct for storing IIP info used in Dequant() + * + * Outputs: updated BitStreamInfo struct + * scalefactors in sfis (short and/or long arrays, as appropriate) + * updated intensityScale and preFlag flags + * + * Return: none + * + * Notes: Illegal Intensity Position = (2^slen) - 1 for MPEG2 scale factors + * + * TODO: optimize the / and % stuff (only do one divide, get modulo x + * with (x / m) * m, etc.) + **************************************************************************************/ +static void UnpackSFMPEG2(BitStreamInfo *bsi, SideInfoSub *sis, ScaleFactorInfoSub *sfis, int gr, int ch, int modeExt, ScaleFactorJS *sfjs) +{ + + int i, sfb, sfcIdx, btIdx, nrIdx; + int slen[4], nr[4]; + int sfCompress, preFlag, intensityScale; + + sfCompress = sis->sfCompress; + preFlag = 0; + intensityScale = 0; + + /* stereo mode bits (1 = on): bit 1 = mid-side on/off, bit 0 = intensity on/off */ + if (! ((modeExt & 0x01) && (ch == 1)) ) { + /* in other words: if ((modeExt & 0x01) == 0 || ch == 0) */ + if (sfCompress < 400) { + /* max slen = floor[(399/16) / 5] = 4 */ + slen[0] = (sfCompress >> 4) / 5; + slen[1]= (sfCompress >> 4) % 5; + slen[2]= (sfCompress & 0x0f) >> 2; + slen[3]= (sfCompress & 0x03); + sfcIdx = 0; + } else if (sfCompress < 500) { + /* max slen = floor[(99/4) / 5] = 4 */ + sfCompress -= 400; + slen[0] = (sfCompress >> 2) / 5; + slen[1]= (sfCompress >> 2) % 5; + slen[2]= (sfCompress & 0x03); + slen[3]= 0; + sfcIdx = 1; + } else { + /* max slen = floor[11/3] = 3 (sfCompress = 9 bits in MPEG2) */ + sfCompress -= 500; + slen[0] = sfCompress / 3; + slen[1] = sfCompress % 3; + slen[2] = slen[3] = 0; + if (sis->mixedBlock) { + /* adjust for long/short mix logic (see comment above in NRTab[] definition) */ + slen[2] = slen[1]; + slen[1] = slen[0]; + } + preFlag = 1; + sfcIdx = 2; + } + } else { + /* intensity stereo ch = 1 (right) */ + intensityScale = sfCompress & 0x01; + sfCompress >>= 1; + if (sfCompress < 180) { + /* max slen = floor[35/6] = 5 (from mod 36) */ + slen[0] = (sfCompress / 36); + slen[1] = (sfCompress % 36) / 6; + slen[2] = (sfCompress % 36) % 6; + slen[3] = 0; + sfcIdx = 3; + } else if (sfCompress < 244) { + /* max slen = floor[63/16] = 3 */ + sfCompress -= 180; + slen[0] = (sfCompress & 0x3f) >> 4; + slen[1] = (sfCompress & 0x0f) >> 2; + slen[2] = (sfCompress & 0x03); + slen[3] = 0; + sfcIdx = 4; + } else { + /* max slen = floor[11/3] = 3 (max sfCompress >> 1 = 511/2 = 255) */ + sfCompress -= 244; + slen[0] = (sfCompress / 3); + slen[1] = (sfCompress % 3); + slen[2] = slen[3] = 0; + sfcIdx = 5; + } + } + + /* set index based on block type: (0,1,3) --> 0, (2 non-mixed) --> 1, (2 mixed) ---> 2 */ + btIdx = 0; + if (sis->blockType == 2) + btIdx = (sis->mixedBlock ? 2 : 1); + for (i = 0; i < 4; i++) + nr[i] = (int)NRTab[sfcIdx][btIdx][i]; + + /* save intensity stereo scale factor info */ + if( (modeExt & 0x01) && (ch == 1) ) { + for (i = 0; i < 4; i++) { + sfjs->slen[i] = slen[i]; + sfjs->nr[i] = nr[i]; + } + sfjs->intensityScale = intensityScale; + } + sis->preFlag = preFlag; + + /* short blocks */ + if(sis->blockType == 2) { + if(sis->mixedBlock) { + /* do long block portion */ + for (sfb=0; sfb < 6; sfb++) { + sfis->l[sfb] = (char)GetBits(bsi, slen[0]); + } + sfb = 3; /* start sfb for short */ + nrIdx = 1; + } else { + /* all short blocks, so start nr, sfb at 0 */ + sfb = 0; + nrIdx = 0; + } + + /* remaining short blocks, sfb just keeps incrementing */ + for ( ; nrIdx <= 3; nrIdx++) { + for (i=0; i < nr[nrIdx]; i++, sfb++) { + sfis->s[sfb][0] = (char)GetBits(bsi, slen[nrIdx]); + sfis->s[sfb][1] = (char)GetBits(bsi, slen[nrIdx]); + sfis->s[sfb][2] = (char)GetBits(bsi, slen[nrIdx]); + } + } + /* last sf band not transmitted */ + sfis->s[12][0] = sfis->s[12][1] = sfis->s[12][2] = 0; + } else { + /* long blocks */ + sfb = 0; + for (nrIdx = 0; nrIdx <= 3; nrIdx++) { + for(i=0; i < nr[nrIdx]; i++, sfb++) { + sfis->l[sfb] = (char)GetBits(bsi, slen[nrIdx]); + } + } + /* last sf band not transmitted */ + sfis->l[21] = sfis->l[22] = 0; + + } +} + +/************************************************************************************** + * Function: UnpackScaleFactors + * + * Description: parse the fields of the MP3 scale factor data section + * + * Inputs: MP3DecInfo structure filled by UnpackFrameHeader() and UnpackSideInfo() + * buffer pointing to the MP3 scale factor data + * pointer to bit offset (0-7) indicating starting bit in buf[0] + * number of bits available in data buffer + * index of current granule and channel + * + * Outputs: updated platform-specific ScaleFactorInfo struct + * updated bitOffset + * + * Return: length (in bytes) of scale factor data, -1 if null input pointers + **************************************************************************************/ +int UnpackScaleFactors(MP3DecInfo *mp3DecInfo, unsigned char *buf, int *bitOffset, int bitsAvail, int gr, int ch) +{ + int bitsUsed; + unsigned char *startBuf; + BitStreamInfo bitStreamInfo, *bsi; + FrameHeader *fh; + SideInfo *si; + ScaleFactorInfo *sfi; + + /* validate pointers */ + if (!mp3DecInfo || !mp3DecInfo->FrameHeaderPS || !mp3DecInfo->SideInfoPS || !mp3DecInfo->ScaleFactorInfoPS) + return -1; + fh = ((FrameHeader *)(mp3DecInfo->FrameHeaderPS)); + si = ((SideInfo *)(mp3DecInfo->SideInfoPS)); + sfi = ((ScaleFactorInfo *)(mp3DecInfo->ScaleFactorInfoPS)); + + /* init GetBits reader */ + startBuf = buf; + bsi = &bitStreamInfo; + SetBitstreamPointer(bsi, (bitsAvail + *bitOffset + 7) / 8, buf); + if (*bitOffset) + GetBits(bsi, *bitOffset); + + if (fh->ver == MPEG1) + UnpackSFMPEG1(bsi, &si->sis[gr][ch], &sfi->sfis[gr][ch], si->scfsi[ch], gr, &sfi->sfis[0][ch]); + else + UnpackSFMPEG2(bsi, &si->sis[gr][ch], &sfi->sfis[gr][ch], gr, ch, fh->modeExt, &sfi->sfjs); + + mp3DecInfo->part23Length[gr][ch] = si->sis[gr][ch].part23Length; + + bitsUsed = CalcBitsUsed(bsi, buf, *bitOffset); + buf += (bitsUsed + *bitOffset) >> 3; + *bitOffset = (bitsUsed + *bitOffset) & 0x07; + + return (buf - startBuf); +} + |