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365 lines
14 KiB
365 lines
14 KiB
/* libSoX ima_rw.c -- codex utilities for WAV_FORMAT_IMA_ADPCM
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* Copyright (C) 1999 Stanley J. Brooks <stabro@megsinet.net>
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*
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* This library is free software; you can redistribute it and/or modify it
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* under the terms of the GNU Lesser General Public License as published by
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* the Free Software Foundation; either version 2.1 of the License, or (at
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* your option) any later version.
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*
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* This library is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser
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* General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public License
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* along with this library; if not, write to the Free Software Foundation,
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* Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#include "sox_i.h"
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#include "ima_rw.h"
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#include <sys/types.h>
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#include <stdio.h>
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#include <stdlib.h>
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/*
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*
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* Lookup tables for IMA ADPCM format
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*
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*/
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#define ISSTMAX 88
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static const int imaStepSizeTable[ISSTMAX + 1] = {
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7, 8, 9, 10, 11, 12, 13, 14, 16, 17, 19, 21, 23, 25, 28, 31, 34,
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37, 41, 45, 50, 55, 60, 66, 73, 80, 88, 97, 107, 118, 130, 143,
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157, 173, 190, 209, 230, 253, 279, 307, 337, 371, 408, 449, 494,
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544, 598, 658, 724, 796, 876, 963, 1060, 1166, 1282, 1411, 1552,
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1707, 1878, 2066, 2272, 2499, 2749, 3024, 3327, 3660, 4026,
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4428, 4871, 5358, 5894, 6484, 7132, 7845, 8630, 9493, 10442,
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11487, 12635, 13899, 15289, 16818, 18500, 20350, 22385, 24623,
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27086, 29794, 32767
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};
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#define imaStateAdjust(c) (((c)<4)? -1:(2*(c)-6))
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/* +0 - +3, decrease step size */
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/* +4 - +7, increase step size */
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/* -0 - -3, decrease step size */
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/* -4 - -7, increase step size */
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static unsigned char imaStateAdjustTable[ISSTMAX+1][8];
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void lsx_ima_init_table(void)
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{
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int i,j,k;
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for (i=0; i<=ISSTMAX; i++) {
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for (j=0; j<8; j++) {
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k = i + imaStateAdjust(j);
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if (k<0) k=0;
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else if (k>ISSTMAX) k=ISSTMAX;
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imaStateAdjustTable[i][j] = k;
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}
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}
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}
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static void ImaExpandS(
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unsigned ch, /* channel number to decode, REQUIRE 0 <= ch < chans */
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unsigned chans, /* total channels */
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const unsigned char *ibuff,/* input buffer[blockAlign] */
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SAMPL *obuff, /* obuff[n] will be output samples */
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int n, /* samples to decode PER channel, REQUIRE n % 8 == 1 */
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unsigned o_inc /* index difference between successive output samples */
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)
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{
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const unsigned char *ip;
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int i_inc;
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SAMPL *op;
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int i, val, state;
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ip = ibuff + 4*ch; /* input pointer to 4-byte block state-initializer */
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i_inc = 4*(chans-1); /* amount by which to incr ip after each 4-byte read */
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val = (short)(ip[0] + (ip[1]<<8)); /* need cast for sign-extend */
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state = ip[2];
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if (state > ISSTMAX) {
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lsx_warn("IMA_ADPCM block ch%d initial-state (%d) out of range", ch, state);
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state = 0;
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}
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/* specs say to ignore ip[3] , but write it as 0 */
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ip += 4+i_inc;
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op = obuff;
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*op = val; /* 1st output sample for this channel */
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op += o_inc;
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for (i = 1; i < n; i++) {
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int step,dp,c,cm;
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if (i&1) { /* 1st of pair */
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cm = *ip & 0x0f;
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} else {
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cm = (*ip++)>>4;
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if ((i&7) == 0) /* ends the 8-sample input block for this channel */
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ip += i_inc; /* skip ip for next group */
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}
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step = imaStepSizeTable[state];
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/* Update the state for the next sample */
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c = cm & 0x07;
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state = imaStateAdjustTable[state][c];
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dp = 0;
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if (c & 4) dp += step;
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step = step >> 1;
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if (c & 2) dp += step;
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step = step >> 1;
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if (c & 1) dp += step;
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step = step >> 1;
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dp += step;
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if (c != cm) {
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val -= dp;
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if (val<-0x8000) val = -0x8000;
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} else {
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val += dp;
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if (val>0x7fff) val = 0x7fff;
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}
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*op = val;
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op += o_inc;
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}
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return;
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}
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/* lsx_ima_block_expand_i() outputs interleaved samples into one output buffer */
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void lsx_ima_block_expand_i(
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unsigned chans, /* total channels */
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const unsigned char *ibuff,/* input buffer[blockAlign] */
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SAMPL *obuff, /* output samples, n*chans */
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int n /* samples to decode PER channel, REQUIRE n % 8 == 1 */
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)
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{
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unsigned ch;
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for (ch=0; ch<chans; ch++)
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ImaExpandS(ch, chans, ibuff, obuff+ch, n, chans);
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}
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/* lsx_ima_block_expand_m() outputs non-interleaved samples into chan separate output buffers */
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void lsx_ima_block_expand_m(
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unsigned chans, /* total channels */
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const unsigned char *ibuff,/* input buffer[blockAlign] */
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SAMPL **obuffs, /* chan output sample buffers, each takes n samples */
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int n /* samples to decode PER channel, REQUIRE n % 8 == 1 */
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)
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{
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unsigned ch;
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for (ch=0; ch<chans; ch++)
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ImaExpandS(ch, chans, ibuff, obuffs[ch], n, 1);
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}
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static int ImaMashS(
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unsigned ch, /* channel number to encode, REQUIRE 0 <= ch < chans */
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unsigned chans, /* total channels */
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int v0, /* value to use as starting prediction0 */
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const SAMPL *ibuff, /* ibuff[] is interleaved input samples */
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int n, /* samples to encode PER channel, REQUIRE n % 8 == 1 */
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int *st, /* input/output state, REQUIRE 0 <= *st <= ISSTMAX */
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unsigned char *obuff /* output buffer[blockAlign], or NULL for no output */
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)
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{
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const SAMPL *ip, *itop;
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unsigned char *op;
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int o_inc = 0; /* set 0 only to shut up gcc's 'might be uninitialized' */
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int i, val;
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int state;
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double d2; /* long long is okay also, speed abt the same */
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ip = ibuff + ch; /* point ip to 1st input sample for this channel */
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itop = ibuff + n*chans;
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val = *ip - v0; ip += chans;/* 1st input sample for this channel */
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d2 = val*val;/* d2 will be sum of squares of errors, given input v0 and *st */
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val = v0;
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op = obuff; /* output pointer (or NULL) */
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if (op) { /* NULL means don't output, just compute the rms error */
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op += 4*ch; /* where to put this channel's 4-byte block state-initializer */
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o_inc = 4*(chans-1); /* amount by which to incr op after each 4-byte written */
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*op++ = val; *op++ = val>>8;
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*op++ = *st; *op++ = 0; /* they could have put a mid-block state-correction here */
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op += o_inc; /* _sigh_ NEVER waste a byte. It's a rule! */
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}
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state = *st;
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for (i = 0; ip < itop; ip+=chans) {
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int step,d,dp,c;
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d = *ip - val; /* difference between last prediction and current sample */
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step = imaStepSizeTable[state];
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c = (abs(d)<<2)/step;
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if (c > 7) c = 7;
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/* Update the state for the next sample */
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state = imaStateAdjustTable[state][c];
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if (op) { /* if we want output, put it in proper place */
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int cm = c;
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if (d<0) cm |= 8;
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if (i&1) { /* odd numbered output */
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*op++ |= (cm<<4);
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if (i == 7) /* ends the 8-sample output block for this channel */
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op += o_inc; /* skip op for next group */
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} else {
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*op = cm;
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}
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i = (i+1) & 0x07;
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}
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dp = 0;
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if (c & 4) dp += step;
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step = step >> 1;
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if (c & 2) dp += step;
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step = step >> 1;
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if (c & 1) dp += step;
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step = step >> 1;
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dp += step;
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if (d<0) {
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val -= dp;
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if (val<-0x8000) val = -0x8000;
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} else {
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val += dp;
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if (val>0x7fff) val = 0x7fff;
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}
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{
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int x = *ip - val;
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d2 += x*x;
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}
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}
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d2 /= n; /* be sure it's non-negative */
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*st = state;
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return (int) sqrt(d2);
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}
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/* mash one channel... if you want to use opt>0, 9 is a reasonable value */
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inline static void ImaMashChannel(
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unsigned ch, /* channel number to encode, REQUIRE 0 <= ch < chans */
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unsigned chans, /* total channels */
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const SAMPL *ip, /* ip[] is interleaved input samples */
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int n, /* samples to encode PER channel, REQUIRE n % 8 == 1 */
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int *st, /* input/output state, REQUIRE 0 <= *st <= ISSTMAX */
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unsigned char *obuff, /* output buffer[blockAlign] */
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int opt /* non-zero allows some cpu-intensive code to improve output */
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)
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{
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int snext;
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int s0,d0;
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s0 = *st;
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if (opt>0) {
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int low,hi,w;
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int low0,hi0;
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snext = s0;
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d0 = ImaMashS(ch, chans, ip[ch], ip,n,&snext, NULL);
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w = 0;
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low=hi=s0;
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low0 = low-opt; if (low0<0) low0=0;
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hi0 = hi+opt; if (hi0>ISSTMAX) hi0=ISSTMAX;
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while (low>low0 || hi<hi0) {
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if (!w && low>low0) {
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int d2;
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snext = --low;
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d2 = ImaMashS(ch, chans, ip[ch], ip,n,&snext, NULL);
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if (d2<d0) {
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d0=d2; s0=low;
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low0 = low-opt; if (low0<0) low0=0;
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hi0 = low+opt; if (hi0>ISSTMAX) hi0=ISSTMAX;
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}
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}
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if (w && hi<hi0) {
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int d2;
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snext = ++hi;
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d2 = ImaMashS(ch, chans, ip[ch], ip,n,&snext, NULL);
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if (d2<d0) {
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d0=d2; s0=hi;
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low0 = hi-opt; if (low0<0) low0=0;
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hi0 = hi+opt; if (hi0>ISSTMAX) hi0=ISSTMAX;
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}
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}
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w=1-w;
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}
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*st = s0;
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}
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ImaMashS(ch, chans, ip[ch], ip,n,st, obuff);
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}
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/* mash one block. if you want to use opt>0, 9 is a reasonable value */
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void lsx_ima_block_mash_i(
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unsigned chans, /* total channels */
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const SAMPL *ip, /* ip[] is interleaved input samples */
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int n, /* samples to encode PER channel, REQUIRE n % 8 == 1 */
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int *st, /* input/output state, REQUIRE 0 <= *st <= ISSTMAX */
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unsigned char *obuff, /* output buffer[blockAlign] */
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int opt /* non-zero allows some cpu-intensive code to improve output */
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)
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{
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unsigned ch;
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for (ch=0; ch<chans; ch++)
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ImaMashChannel(ch, chans, ip, n, st+ch, obuff, opt);
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}
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/*
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* lsx_ima_samples_in(dataLen, chans, blockAlign, samplesPerBlock)
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* returns the number of samples/channel which would go
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* in the dataLen, given the other parameters ...
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* if input samplesPerBlock is 0, then returns the max
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* samplesPerBlock which would go into a block of size blockAlign
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* Yes, it is confusing.
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*/
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size_t lsx_ima_samples_in(
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size_t dataLen,
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size_t chans,
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size_t blockAlign,
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size_t samplesPerBlock
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)
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{
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size_t m, n;
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if (samplesPerBlock) {
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n = (dataLen / blockAlign) * samplesPerBlock;
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m = (dataLen % blockAlign);
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} else {
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n = 0;
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m = blockAlign;
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}
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if (m >= (size_t)4*chans) {
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m -= 4*chans; /* number of bytes beyond block-header */
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m /= 4*chans; /* number of 4-byte blocks/channel beyond header */
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m = 8*m + 1; /* samples/chan beyond header + 1 in header */
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if (samplesPerBlock && m > samplesPerBlock) m = samplesPerBlock;
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n += m;
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}
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return n;
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/*wSamplesPerBlock = ((wBlockAlign - 4*wChannels)/(4*wChannels))*8 + 1;*/
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}
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/*
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* size_t lsx_ima_bytes_per_block(chans, samplesPerBlock)
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* return minimum blocksize which would be required
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* to encode number of chans with given samplesPerBlock
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*/
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size_t lsx_ima_bytes_per_block(
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size_t chans,
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size_t samplesPerBlock
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)
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{
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size_t n;
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/* per channel, ima has blocks of len 4, the 1st has 1st sample, the others
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* up to 8 samples per block,
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* so number of later blocks is (nsamp-1 + 7)/8, total blocks/chan is
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* (nsamp-1+7)/8 + 1 = (nsamp+14)/8
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*/
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n = ((size_t)samplesPerBlock + 14)/8 * 4 * chans;
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return n;
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}
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