/* @(#)resample.c 1.24 07/07/28 Copyright 1998,1999,2000 Heiko Eissfeldt, Copyright 2004-2006 J. Schilling */
#ifndef lint
static char sccsid[] =
"@(#)resample.c 1.24 07/07/28 Copyright 1998,1999,2000 Heiko Eissfeldt, Copyright 2004-2006 J. Schilling";
#endif
/*
* resampling module
*
* The audio data has been read. Here are the
* functions to ensure a correct continuation
* of the output stream and to convert to a
* lower sample rate.
*
*/
/*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License, Version 1.0 only
* (the "License"). You may not use this file except in compliance
* with the License.
*
* See the file CDDL.Schily.txt in this distribution for details.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file CDDL.Schily.txt from this distribution.
*/
#undef DEBUG_VOTE_ENDIANESS
#undef DEBUG_SHIFTS /* simulate bad cdrom drives */
#undef DEBUG_MATCHING
#undef SHOW_JITTER
#undef CHECK_MEM
#include "config.h"
#include <schily/time.h>
#include <stdio.h>
#include <schily/stdlib.h>
#include <schily/utypes.h>
#include <schily/unistd.h>
#include <schily/standard.h>
#include <schily/string.h>
#include <limits.h>
#include <assert.h>
#include <math.h>
#include <schily/schily.h>
#include <scg/scsitransp.h>
#include "mytype.h"
#include "cdda2wav.h"
#include "interface.h"
#include "byteorder.h"
#include "ringbuff.h"
#include "resample.h"
#include "toc.h"
#include "sndfile.h"
#include "sndconfig.h"
#include "global.h"
#include "exitcodes.h"
int waitforsignal = 0; /* flag: wait for any audio response */
int any_signal = 0;
short undersampling; /* conversion factor */
short samples_to_do; /* loop variable for conversion */
int Halved; /* interpolate due to non integral divider */
static long lsum = 0, rsum = 0; /* accumulator for left/right channel */
static long ls2 = 0, rs2 = 0, ls3 = 0, rs3 = 0, auxl = 0, auxr = 0;
static const unsigned char *my_symmemmem __PR((const unsigned char *HAYSTACK,
const size_t HAYSTACK_LEN,
const unsigned char *const NEEDLE,
const size_t NEEDLE_LEN));
static const unsigned char *my_memmem __PR((const unsigned char *HAYSTACK,
const size_t HAYSTACK_LEN,
const unsigned char *const NEEDLE,
const size_t NEEDLE_LEN));
static const unsigned char *my_memrmem __PR((const unsigned char *HAYSTACK,
const size_t HAYSTACK_LEN,
const unsigned char *const NEEDLE,
const size_t NEEDLE_LEN));
static const unsigned char *sync_buffers __PR((const unsigned char *const newbuf));
static long interpolate __PR((long p1, long p2, long p3));
static void emit_sample __PR((long lsumval, long rsumval,
long channels));
static void change_endianness __PR((UINT4 *pSam,
unsigned int Samples));
static void swap_channels __PR((UINT4 *pSam,
unsigned int Samples));
static int guess_endianess __PR((UINT4 *p, Int16_t *p2,
unsigned int SamplesToDo));
#ifdef CHECK_MEM
static void
check_mem __PR((const unsigned char *p, unsigned long amount,
const unsigned char *q,
unsigned line, char *file));
static void
check_mem(p, amount, q, line, file)
const unsigned char *p;
unsigned long amount;
const unsigned char *q;
unsigned line;
char *file;
{
if (p < q || p+amount > q + ENTRY_SIZE) {
errmsgno(EX_BAD,
"File %s, line %u: invalid buffer range (%p - %p), allowed is (%p - %p).\n",
file, line, p, p+amount-1, q, q + ENTRY_SIZE-1);
exit(INTERNAL_ERROR);
}
}
#endif
#ifdef DEBUG_MATCHING
int
memcmp(const void * a, const void * b, size_t c)
{
return (1);
}
#endif
static const unsigned char *
my_symmemmem(HAYSTACK, HAYSTACK_LEN, NEEDLE, NEEDLE_LEN)
const unsigned char *HAYSTACK;
const size_t HAYSTACK_LEN;
const unsigned char *const NEEDLE;
const size_t NEEDLE_LEN;
{
const unsigned char *const UPPER_LIMIT = HAYSTACK +
HAYSTACK_LEN -
NEEDLE_LEN - 1;
const unsigned char *HAYSTACK2 = HAYSTACK-1;
while (HAYSTACK <= UPPER_LIMIT) {
if (memcmp(NEEDLE, HAYSTACK, NEEDLE_LEN) == 0) {
return (HAYSTACK);
} else {
if (memcmp(NEEDLE, HAYSTACK2, NEEDLE_LEN) == 0) {
return (HAYSTACK2);
}
HAYSTACK2--;
HAYSTACK++;
}
}
#ifdef DEBUG_MATCHING
HAYSTACK2++;
HAYSTACK--;
fprintf(stderr, "scompared %p-%p with %p-%p (%p)\n",
NEEDLE, NEEDLE + NEEDLE_LEN-1,
HAYSTACK2, HAYSTACK + NEEDLE_LEN-1, HAYSTACK);
#endif
return (NULL);
}
static const unsigned char *
my_memmem(HAYSTACK, HAYSTACK_LEN, NEEDLE, NEEDLE_LEN)
const unsigned char *HAYSTACK;
const size_t HAYSTACK_LEN;
const unsigned char *const NEEDLE;
const size_t NEEDLE_LEN;
{
const unsigned char *const UPPER_LIMIT = HAYSTACK +
HAYSTACK_LEN -
NEEDLE_LEN;
while (HAYSTACK <= UPPER_LIMIT) {
if (memcmp(NEEDLE, HAYSTACK, NEEDLE_LEN) == 0) {
return (HAYSTACK);
} else {
HAYSTACK++;
}
}
#ifdef DEBUG_MATCHING
HAYSTACK--;
fprintf(stderr, "fcompared %p-%p with %p-%p (%p)\n",
NEEDLE, NEEDLE + NEEDLE_LEN-1,
HAYSTACK - HAYSTACK_LEN + NEEDLE_LEN,
HAYSTACK + NEEDLE_LEN-1,
HAYSTACK);
#endif
return (NULL);
}
static const unsigned char *
my_memrmem(HAYSTACK, HAYSTACK_LEN, NEEDLE, NEEDLE_LEN)
const unsigned char *HAYSTACK;
const size_t HAYSTACK_LEN;
const unsigned char *const NEEDLE;
const size_t NEEDLE_LEN;
{
const unsigned char *const LOWER_LIMIT = HAYSTACK -
(HAYSTACK_LEN - 1);
while (HAYSTACK >= LOWER_LIMIT) {
if (memcmp(NEEDLE, HAYSTACK, NEEDLE_LEN) == 0) {
return (HAYSTACK);
} else {
HAYSTACK--;
}
}
#ifdef DEBUG_MATCHING
HAYSTACK++;
fprintf(stderr, "bcompared %p-%p with %p-%p (%p)\n",
NEEDLE, NEEDLE + NEEDLE_LEN-1,
HAYSTACK, HAYSTACK + (HAYSTACK_LEN - 1),
HAYSTACK + (HAYSTACK_LEN - 1) - NEEDLE_LEN - 1);
#endif
return (NULL);
}
/* find continuation in new buffer */
static const unsigned char *
sync_buffers(newbuf)
const unsigned char *const newbuf;
{
const unsigned char *retval = newbuf;
if (global.overlap != 0) {
/*
* find position of SYNC_SIZE bytes
* of the old buffer in the new buffer
*/
size_t haystack_len;
const size_t needle_len = SYNC_SIZE;
const unsigned char *const oldbuf =
(const unsigned char *)
(get_previous_read_buffer()->data);
const unsigned char *haystack;
const unsigned char *needle;
/*
* compare the previous buffer with the new one
*
* 1. symmetrical search:
* look for the last SYNC_SIZE bytes of the previous buffer
* in the new buffer (from the optimum to the outer
* positions).
*
* 2. if the first approach did not find anything do forward
* search look for the last SYNC_SIZE bytes of the previous
* buffer in the new buffer (from behind the overlap to the
* end).
*/
haystack_len = min((global.nsectors - global.overlap) *
CD_FRAMESIZE_RAW
+SYNC_SIZE+1,
global.overlap*CD_FRAMESIZE_RAW);
/*
* expected here
*/
haystack = newbuf + CD_FRAMESIZE_RAW *
global.overlap - SYNC_SIZE;
needle = oldbuf + CD_FRAMESIZE_RAW*global.nsectors - SYNC_SIZE;
#ifdef DEBUG_MATCHING
fprintf(stderr, "oldbuf %p-%p new %p-%p %u %u %u\n",
oldbuf, oldbuf + CD_FRAMESIZE_RAW*global.nsectors - 1,
newbuf, newbuf + CD_FRAMESIZE_RAW*global.nsectors - 1,
CD_FRAMESIZE_RAW*global.nsectors, global.nsectors,
global.overlap);
#endif
retval = my_symmemmem(haystack, haystack_len, needle,
needle_len);
if (retval != NULL) {
retval += SYNC_SIZE;
} else {
/*
* fallback to asymmetrical search
*
* if there is no asymmetrical part left,
* return with 'not found'
*/
if (2*global.overlap == global.nsectors) {
retval = NULL;
} else if (2*global.overlap > global.nsectors) {
/*
* the asymmetrical part is in front,
* search backwards
*/
haystack_len = (2*global.overlap-global.nsectors)*CD_FRAMESIZE_RAW;
haystack = newbuf + haystack_len - 1;
retval = my_memrmem(haystack, haystack_len, needle, needle_len);
} else {
/*
* the asymmetrical part is at the end,
* search forward
*/
haystack = newbuf + 2*(global.overlap*CD_FRAMESIZE_RAW - SYNC_SIZE);
haystack_len = (global.nsectors-2*global.overlap)*CD_FRAMESIZE_RAW + 2*SYNC_SIZE;
retval = my_memmem(haystack, haystack_len, needle, needle_len);
}
if (retval != NULL)
retval += SYNC_SIZE;
}
#ifdef SHOW_JITTER
if (retval) {
fprintf(stderr, "%d\n",
retval-(newbuf+global.overlap*CD_FRAMESIZE_RAW));
} else {
fprintf(stderr, "no match\n");
}
#endif
}
return (retval);
}
/*
* quadratic interpolation
* p1, p3 span the interval 0 - 2. give interpolated value for 1/2
*/
static long int
interpolate(p1, p2, p3)
long int p1;
long int p2;
long int p3;
{
return ((3L*p1 + 6L*p2 - p3)/8L);
}
static unsigned char *pStart; /* running ptr defining end of output buffer */
static unsigned char *pDst; /* start of output buffer */
/*
* Write the filtered sample into the output buffer.
*/
static void
emit_sample(lsumval, rsumval, channels)
long lsumval;
long rsumval;
long channels;
{
if (global.findminmax) {
if (rsumval > global.maxamp[0])
global.maxamp[0] = rsumval;
if (rsumval < global.minamp[0])
global.minamp[0] = rsumval;
if (lsumval < global.minamp[1])
global.minamp[1] = lsumval;
if (lsumval > global.maxamp[1])
global.maxamp[1] = lsumval;
}
/*
* convert to output format
*/
if (channels == 1) {
Int16_t sum;
/*
* mono section
*/
sum = (lsumval + rsumval) >> (global.sh_bits + 1);
if (global.sh_bits == 8) {
if (waitforsignal == 1) {
if (any_signal == 0) {
if (((char) sum) != '\0') {
pStart = (unsigned char *) pDst;
any_signal = 1;
*pDst++ = (unsigned char) sum + (1 << 7);
} else
global.SkippedSamples++;
} else
*pDst++ = (unsigned char) sum + (1 << 7);
} else
*pDst++ = (unsigned char) sum + (1 << 7);
} else {
Int16_t *myptr = (Int16_t *) pDst;
if (waitforsignal == 1) {
if (any_signal == 0) {
if (sum != 0) {
pStart = (unsigned char *) pDst;
any_signal = 1;
*myptr = sum; pDst += sizeof (Int16_t);
} else
global.SkippedSamples++;
} else {
*myptr = sum; pDst += sizeof (Int16_t);
}
} else {
*myptr = sum; pDst += sizeof (Int16_t);
}
}
} else {
/*
* stereo section
*/
lsumval >>= global.sh_bits;
rsumval >>= global.sh_bits;
if (global.sh_bits == 8) {
if (waitforsignal == 1) {
if (any_signal == 0) {
if ((((char) lsumval != '\0') || ((char) rsumval != '\0'))) {
pStart = (unsigned char *) pDst;
any_signal = 1;
*pDst++ = (unsigned char)(short) lsumval + (1 << 7);
*pDst++ = (unsigned char)(short) rsumval + (1 << 7);
} else
global.SkippedSamples++;
} else {
*pDst++ = (unsigned char)(short) lsumval + (1 << 7);
*pDst++ = (unsigned char)(short) rsumval + (1 << 7);
}
} else {
*pDst++ = (unsigned char)(short) lsumval + (1 << 7);
*pDst++ = (unsigned char)(short) rsumval + (1 << 7);
}
} else {
Int16_t *myptr = (Int16_t *) pDst;
if (waitforsignal == 1) {
if (any_signal == 0) {
if ((((Int16_t) lsumval != 0) || ((Int16_t) rsumval != 0))) {
pStart = (unsigned char *) pDst;
any_signal = 1;
*myptr++ = (Int16_t) lsumval;
*myptr = (Int16_t) rsumval;
pDst += 2*sizeof (Int16_t);
} else
global.SkippedSamples++;
} else {
*myptr++ = (Int16_t) lsumval;
*myptr = (Int16_t) rsumval;
pDst += 2*sizeof (Int16_t);
}
} else {
*myptr++ = (Int16_t) lsumval;
*myptr = (Int16_t) rsumval;
pDst += 2*sizeof (Int16_t);
}
}
}
}
static void
change_endianness(pSam, Samples)
UINT4 *pSam;
unsigned int Samples;
{
UINT4 *pend = (pSam + Samples);
/*
* type UINT4 may not be greater than the assumed biggest type
*/
#if (SIZEOF_LONG_INT < 4)
error type unsigned long is too small
#endif
#if (SIZEOF_LONG_INT == 4)
unsigned long *plong = (unsigned long *)pSam;
for (; plong < pend; ) {
*plong = ((*plong >> 8L) & UINT_C(0x00ff00ff)) |
((*plong << 8L) & UINT_C(0xff00ff00));
plong++;
}
#else /* sizeof long unsigned > 4 bytes */
#if (SIZEOF_LONG_INT == 8)
#define INTEGRAL_LONGS (SIZEOF_LONG_INT-1UL)
register unsigned long *plong;
unsigned long *pend0 = (unsigned long *) (((unsigned long) pend) & ~ INTEGRAL_LONGS);
if (((unsigned long) pSam) & INTEGRAL_LONGS) {
*pSam = ((*pSam >> 8L) & UINT_C(0x00ff00ff)) |
((*pSam << 8L) & UINT_C(0xff00ff00));
pSam++;
}
plong = (unsigned long *)pSam;
for (; plong < pend0; ) {
*plong = ((*plong >> 8L) & ULONG_C(0x00ff00ff00ff00ff)) |
((*plong << 8L) & ULONG_C(0xff00ff00ff00ff00));
plong++;
}
if (((unsigned long *) pend) != pend0) {
UINT4 *pint = (UINT4 *) pend0;
for (; pint < pend; ) {
*pint = ((*pint >> 8) & UINT_C(0x00ff00ff)) |
((*pint << 8) & UINT_C(0xff00ff00));
pint++;
}
}
#else /* sizeof long unsigned > 4 bytes but not 8 */
{
UINT4 *pint = pSam;
for (; pint < pend; ) {
*pint = ((*pint >> 8) & UINT_C(0x00ff00ff)) |
((*pint << 8) & UINT_C(0xff00ff00));
pint++;
}
}
#endif
#endif
}
static void
swap_channels(pSam, Samples)
UINT4 *pSam;
unsigned int Samples;
{
UINT4 *pend = (pSam + Samples);
/*
* type UINT4 may not be greater than the assumed biggest type
*/
#if (SIZEOF_LONG_INT < 4)
error type unsigned long is too small
#endif
#if (SIZEOF_LONG_INT == 4)
unsigned long *plong = (unsigned long *)pSam;
for (; plong < pend; ) {
*plong = ((*plong >> 16L) & UINT_C(0x0000ffff)) |
((*plong << 16L) & UINT_C(0xffff0000));
plong++;
}
#else /* sizeof long unsigned > 4 bytes */
#if (SIZEOF_LONG_INT == 8)
#define INTEGRAL_LONGS (SIZEOF_LONG_INT-1UL)
register unsigned long *plong;
unsigned long *pend0 = (unsigned long *) (((unsigned long) pend) & ~ INTEGRAL_LONGS);
if (((unsigned long) pSam) & INTEGRAL_LONGS) {
*pSam = ((*pSam >> 16L) & UINT_C(0x0000ffff)) |
((*pSam << 16L) & UINT_C(0xffff0000));
pSam++;
}
plong = (unsigned long *)pSam;
for (; plong < pend0; ) {
*plong = ((*plong >> 16L) & ULONG_C(0x0000ffff0000ffff)) |
((*plong << 16L) & ULONG_C(0xffff0000ffff0000));
plong++;
}
if (((unsigned long *) pend) != pend0) {
UINT4 *pint = (UINT4 *) pend0;
for (; pint < pend; ) {
*pint = ((*pint >> 16L) & UINT_C(0x0000ffff)) |
((*pint << 16L) & UINT_C(0xffff0000));
pint++;
}
}
#else /* sizeof long unsigned > 4 bytes but not 8 */
{
UINT4 *pint = pSam;
for (; pint < pend; ) {
*pint = ((*pint >> 16L) & UINT_C(0x0000ffff)) |
((*pint << 16L) & UINT_C(0xffff0000));
pint++;
}
}
#endif
#endif
}
#ifdef ECHO_TO_SOUNDCARD
static long ReSampleBuffer __PR((unsigned char *p, unsigned char *newp,
long samples, int samplesize));
static long
ReSampleBuffer(p, newp, samples, samplesize)
unsigned char *p;
unsigned char *newp;
long samples;
int samplesize;
{
double idx = 0.0;
UINT4 di = 0;
UINT4 si = 0;
if (global.playback_rate == 100.0) {
memcpy(newp, p, samplesize* samples);
di = samples;
} else while (si < (UINT4)samples) {
memcpy(newp+(di*samplesize), p+(si*samplesize), samplesize);
idx += (double)(global.playback_rate/100.0);
si = (UINT4)idx;
di++;
}
return (di*samplesize);
}
#endif
static int
guess_endianess(p, p2, SamplesToDo)
UINT4 *p;
Int16_t *p2;
unsigned SamplesToDo;
{
/*
* analyse samples
*/
int vote_for_little = 0;
int vote_for_big = 0;
int total_votes;
while (((UINT4 *)p2 - p) + (unsigned) 1 < SamplesToDo) {
unsigned char *p3 = (unsigned char *)p2;
#if MY_LITTLE_ENDIAN == 1
int diff_lowl = *(p2+0) - *(p2+2);
int diff_lowr = *(p2+1) - *(p2+3);
int diff_bigl = ((*(p3) << 8) + *(p3+1)) - ((*(p3+4) << 8) + *(p3+5));
int diff_bigr = ((*(p3+2) << 8) + *(p3+3)) - ((*(p3+6) << 8) + *(p3+7));
#else
int diff_lowl = ((*(p3+1) << 8) + *(p3)) - ((*(p3+5) << 8) + *(p3+4));
int diff_lowr = ((*(p3+3) << 8) + *(p3+2)) - ((*(p3+7) << 8) + *(p3+6));
int diff_bigl = *(p2+0) - *(p2+2);
int diff_bigr = *(p2+1) - *(p2+3);
#endif
if ((abs(diff_lowl) + abs(diff_lowr)) <
(abs(diff_bigl) + abs(diff_bigr))) {
vote_for_little++;
} else {
if ((abs(diff_lowl) + abs(diff_lowr)) >
(abs(diff_bigl) + abs(diff_bigr))) {
vote_for_big++;
}
}
p2 += 2;
}
#ifdef DEBUG_VOTE_ENDIANESS
if (global.quiet != 1) {
fprintf(stderr,
"votes for little: %4d, votes for big: %4d\n",
vote_for_little, vote_for_big);
}
#endif
total_votes = vote_for_big + vote_for_little;
if (total_votes < 3 ||
abs(vote_for_big - vote_for_little) < total_votes/3) {
return (-1);
} else {
if (vote_for_big > vote_for_little)
return (1);
else
return (0);
}
}
int jitterShift = 0;
void
handle_inputendianess(p, SamplesToDo)
UINT4 *p;
unsigned SamplesToDo;
{
/*
* if endianess is unknown, guess endianess based on
* differences between succesive samples. If endianess
* is correct, the differences are smaller than with the
* opposite byte order.
*/
if ((*in_lendian) < 0) {
Int16_t *p2 = (Int16_t *)p;
/*
* skip constant samples
*/
while ((((UINT4 *)p2 - p) + (unsigned) 1 < SamplesToDo) &&
*p2 == *(p2+2))
p2++;
if (((UINT4 *)p2 - p) + (unsigned) 1 < SamplesToDo) {
switch (guess_endianess(p, p2, SamplesToDo)) {
case -1: break;
case 1: (*in_lendian) = 0;
#if 0
if (global.quiet != 1) {
fprintf(stderr,
"big endian detected\n");
}
#endif
break;
case 0: (*in_lendian) = 1;
#if 0
if (global.quiet != 1) {
fprintf(stderr,
"little endian detected\n");
}
#endif
break;
}
}
}
/*
* ENDIAN ISSUES:
* the individual endianess of cdrom/cd-writer, cpu,
* sound card and audio output format need a careful treatment.
*
* For possible sample processing (rate conversion) we need
* the samples in cpu byte order. This is the first conversion.
*
* After processing it depends on the endianness of the output
* format, whether a second conversion is needed.
*
*/
if (global.need_hostorder && (*in_lendian) != MY_LITTLE_ENDIAN) {
/*
* change endianess of delivered samples to native cpu order
*/
change_endianness(p, SamplesToDo);
}
}
unsigned char *
synchronize(p, SamplesToDo, TotSamplesDone)
UINT4 *p;
unsigned SamplesToDo;
unsigned TotSamplesDone;
{
static int jitter = 0;
char *pSrc; /* start of cdrom buffer */
/*
* synchronisation code
*/
if (TotSamplesDone != 0 && global.overlap != 0 &&
SamplesToDo > CD_FRAMESAMPLES) {
pSrc = (char *) sync_buffers((unsigned char *)p);
if (!pSrc) {
return (NULL);
}
if (pSrc) {
jitter = ((unsigned char *)pSrc -
(((unsigned char *)p) +
global.overlap*CD_FRAMESIZE_RAW))/4;
jitterShift += jitter;
SamplesToDo -= jitter + global.overlap*CD_FRAMESAMPLES;
#if 0
fprintf(stderr,
"Length: pre %d, diff1 %ld, diff2 %ld, min %ld\n",
SamplesToDo,
(TotSamplesWanted - TotSamplesDone),
SamplesNeeded((TotSamplesWanted - TotSamplesDone),
undersampling),
min(SamplesToDo,
SamplesNeeded((TotSamplesWanted - TotSamplesDone),
undersampling)));
#endif
}
} else {
pSrc = (char *) p;
}
return ((unsigned char *) pSrc);
}
/*
* convert cdda data to required output format
* sync code for unreliable cdroms included
*/
long
SaveBuffer(p, SamplesToDo, TotSamplesDone)
UINT4 *p;
unsigned long SamplesToDo;
unsigned long *TotSamplesDone;
{
UINT4 *pSrc; /* start of cdrom buffer */
UINT4 *pSrcStop; /* end of cdrom buffer */
/*
* in case of different endianness between host and output format,
* or channel swaps, or deemphasizing
* copy in a seperate buffer and modify the local copy
*/
if (((((!global.need_hostorder &&
global.need_big_endian == (*in_lendian)) ||
(global.need_hostorder && global.need_big_endian != MY_BIG_ENDIAN)) ||
(global.deemphasize != 0)) && (global.OutSampleSize > 1)) ||
global.swapchannels != 0) {
static UINT4 *localoutputbuffer;
if (localoutputbuffer == NULL) {
localoutputbuffer = malloc(global.nsectors*CD_FRAMESIZE_RAW);
if (localoutputbuffer == NULL) {
errmsg("Cannot allocate local buffer.\n");
return (1);
}
}
memcpy(localoutputbuffer, p, SamplesToDo*4);
p = localoutputbuffer;
}
pSrc = p;
pDst = (unsigned char *) p;
pStart = (unsigned char *) pSrc;
pSrcStop = pSrc + SamplesToDo;
/*
* code for subsampling and output stage
*/
if (global.ismono && global.findmono) {
Int16_t *pmm;
for (pmm = (Int16_t *)pStart;
(UINT4 *) pmm < pSrcStop; pmm += 2) {
if (*pmm != *(pmm+1)) {
global.ismono = 0;
break;
}
}
}
/*
* optimize the case of no conversion
*/
if (1 && undersampling == 1 && samples_to_do == 1 &&
global.channels == 2 && global.OutSampleSize == 2 && Halved == 0) {
/*
* output format is the original cdda format ->
* just forward the buffer
*/
if (waitforsignal != 0 && any_signal == 0) {
UINT4 *myptr = (UINT4 *)pStart;
while (myptr < pSrcStop && *myptr == 0)
myptr++;
pStart = (unsigned char *) myptr;
/*
* scan for first signal
*/
if ((UINT4 *)pStart != pSrcStop) {
/*
* first non null amplitude is found in buffer
*/
any_signal = 1;
global.SkippedSamples += ((UINT4 *)pStart - p);
} else {
global.SkippedSamples += (pSrcStop - p);
}
}
pDst = (unsigned char *) pSrcStop; /* set pDst to end */
if (global.deemphasize &&
(Get_Preemphasis(get_current_track()))) {
/*
* this implements an attenuation treble shelving
* filter to undo the effect of pre-emphasis.
* The filter is of a recursive first order
*/
static Int16_t lastin[2] = { 0, 0 };
static double lastout[2] = { 0.0, 0.0 };
Int16_t *pmm;
/*
* Here is the gnuplot file for the frequency response
* of the deemphasis. The error is below +-0.1dB
*/
#ifdef GNU_PLOT_PROGRAM
/* BEGIN CSTYLED */
/*
# first define the ideal filter. We use the tenfold sampling frequency.
T=1./441000.
OmegaU=1./15E-6
OmegaL=15./50.*OmegaU
V0=OmegaL/OmegaU
H0=V0-1.
B=V0*tan(OmegaU*T/2.)
# the coefficients follow
a1=(B - 1.)/(B + 1.)
b0=(1.0 + (1.0 - a1) * H0/2.)
b1=(a1 + (a1 - 1.0) * H0/2.)
# helper variables
D=b1/b0
o=2*pi*T
H2(f)=b0*sqrt((1+2*cos(f*o)*D+D*D)/(1+2*cos(f*o)*a1+a1*a1))
# now approximate the ideal curve with a fitted one for sampling frequency
# of 44100 Hz.
T2=1./44100.
V02=0.3365
OmegaU2=1./19E-6
B2=V02*tan(OmegaU2*T2/2.)
# the coefficients follow
a12=(B2 - 1.)/(B2 + 1.)
b02=(1.0 + (1.0 - a12) * (V02-1.)/2.)
b12=(a12 + (a12 - 1.0) * (V02-1.)/2.)
# helper variables
D2=b12/b02
o2=2*pi*T2
H(f)=b02*sqrt((1+2*cos(f*o2)*D2+D2*D2)/(1+2*cos(f*o2)*a12+a12*a12))
# plot best, real, ideal, level with halved attenuation,
# level at full attentuation, 10fold magnified error
set logscale x
set grid xtics ytics mxtics mytics
plot [f=1000:20000] [-12:2] 20*log10(H(f)),20*log10(H2(f)), 20*log10(OmegaL/(2*pi*f)), 0.5*20*log10(V0), 20*log10(V0), 200*log10(H(f)/H2(f))
pause -1 "Hit return to continue"
*/
/* END CSTYLED */
#endif
#ifdef TEST
#define V0 0.3365
#define OMEGAG (1./19e-6)
#define T (1./44100.)
#define H0 (V0-1.)
#define B (V0*tan((OMEGAG * T)/2.0))
#define a1 ((B - 1.)/(B + 1.))
#define b0 (1.0 + (1.0 - a1) * H0/2.0)
#define b1 (a1 + (a1 - 1.0) * H0/2.0)
#undef V0
#undef OMEGAG
#undef T
#undef H0
#undef B
#else
#define a1 -0.62786881719628784282
#define b0 0.45995451989513153057
#define b1 -0.08782333709141937339
#endif
for (pmm = (Int16_t *)pStart; pmm < (Int16_t *)pDst; ) {
lastout[0] = *pmm * b0 + lastin[0] * b1 - lastout[0] * a1;
lastin[0] = *pmm;
*pmm++ = lastout[0] > 0.0 ? lastout[0] + 0.5 : lastout[0] - 0.5;
lastout[1] = *pmm * b0 + lastin[1] * b1 - lastout[1] * a1;
lastin[1] = *pmm;
*pmm++ = lastout[1] > 0.0 ? lastout[1] + 0.5 : lastout[1] - 0.5;
}
#undef a1
#undef b0
#undef b1
}
if (global.swapchannels == 1) {
swap_channels((UINT4 *)pStart, SamplesToDo);
}
if (global.findminmax) {
Int16_t *pmm;
for (pmm = (Int16_t *)pStart;
pmm < (Int16_t *)pDst; pmm++) {
if (*pmm < global.minamp[1])
global.minamp[1] = *pmm;
if (*pmm > global.maxamp[1])
global.maxamp[1] = *pmm;
pmm++;
if (*pmm < global.minamp[0])
global.minamp[0] = *pmm;
if (*pmm > global.maxamp[0])
global.maxamp[0] = *pmm;
}
}
} else {
#define none_missing 0
#define one_missing 1
#define two_missing 2
#define collecting 3
static int sample_state = collecting;
static int Toggle_on = 0;
if (global.channels == 2 && global.swapchannels == 1) {
swap_channels((UINT4 *)pStart, SamplesToDo);
}
/*
* conversion required
*/
while (pSrc < pSrcStop) {
long l;
long r;
long iSamples_left = (pSrcStop - pSrc) / sizeof (Int16_t) / 2;
Int16_t *myptr = (Int16_t *) pSrc;
/*
* LSB l, MSB l
*/
l = *myptr++; /* left channel */
r = *myptr++; /* right channel */
pSrc = (UINT4 *) myptr;
switch (sample_state) {
case two_missing:
two__missing:
ls2 += l; rs2 += r;
if (undersampling > 1) {
ls3 += l; rs3 += r;
}
sample_state = one_missing;
break;
case one_missing:
auxl = l; auxr = r;
ls3 += l; rs3 += r;
sample_state = none_missing;
/* FALLTHROUGH */
none__missing:
case none_missing:
/*
* Filtered samples are complete.
* Now interpolate and scale.
*/
if (Halved != 0 && Toggle_on == 0) {
lsum = interpolate(lsum, ls2, ls3)/(int) undersampling;
rsum = interpolate(rsum, rs2, rs3)/(int) undersampling;
} else {
lsum /= (int) undersampling;
rsum /= (int) undersampling;
}
emit_sample(lsum, rsum, global.channels);
/*
* reload counter
*/
samples_to_do = undersampling - 1;
lsum = auxl;
rsum = auxr;
/*
* reset sample register
*/
auxl = ls2 = ls3 = 0;
auxr = rs2 = rs3 = 0;
Toggle_on ^= 1;
sample_state = collecting;
break;
case collecting:
if (samples_to_do > 0) {
samples_to_do--;
if (Halved != 0 && Toggle_on == 0) {
/*
* Divider x.5 : we need data
* for quadratic interpolation
*/
iSamples_left--;
lsum += l; rsum += r;
if (samples_to_do < undersampling - 1) {
ls2 += l; rs2 += r;
}
if (samples_to_do < undersampling - 2) {
ls3 += l; rs3 += r;
}
} else {
/*
* integral divider
*/
lsum += l;
rsum += r;
iSamples_left--;
}
} else {
if (Halved != 0 && Toggle_on == 0) {
sample_state = two_missing;
goto two__missing;
} else {
auxl = l;
auxr = r;
sample_state = none_missing;
goto none__missing;
}
}
break;
} /* switch state */
} /* while */
/*
* flush_buffer
*/
if ((samples_to_do == 0 && Halved == 0)) {
if (Halved != 0 && Toggle_on == 0) {
lsum = interpolate(lsum, ls2, ls3)/(int) undersampling;
rsum = interpolate(rsum, rs2, rs3)/(int) undersampling;
} else {
lsum /= (int) undersampling;
rsum /= (int) undersampling;
}
emit_sample(lsum, rsum, global.channels);
/*
* reload counter
*/
samples_to_do = undersampling;
/*
* reset sample register
*/
lsum = auxl = ls2 = ls3 = 0;
rsum = auxr = rs2 = rs3 = 0;
Toggle_on ^= 1;
sample_state = collecting;
}
} /* if optimize else */
if (waitforsignal == 0)
pStart = (unsigned char *)p;
if (waitforsignal == 0 || any_signal != 0) {
int retval = 0;
unsigned outlen;
unsigned todo;
assert(pDst >= pStart);
outlen = (size_t) (pDst - pStart);
if (outlen == 0)
return (0);
#ifdef ECHO_TO_SOUNDCARD
/*
* this assumes the soundcard needs samples in native
* cpu byte order
*/
if (global.echo != 0) {
static unsigned char *newp;
unsigned newlen;
newlen = (100*(outlen/4))/global.playback_rate;
newlen = (newlen*4);
if ((newp != NULL) || (newp = malloc(2*global.nsectors*CD_FRAMESIZE_RAW+32))) {
newlen = ReSampleBuffer(pStart, newp, outlen/4, global.OutSampleSize*global.channels);
write_snd_device((char *)newp, newlen);
}
}
#endif
if (global.no_file != 0) {
*TotSamplesDone += SamplesToDo;
return (0);
}
if ((!global.need_hostorder && global.need_big_endian == (*in_lendian)) ||
(global.need_hostorder && global.need_big_endian != MY_BIG_ENDIAN)) {
if (global.OutSampleSize > 1) {
/*
* change endianness from input sample or native cpu order
* to required output endianness
*/
change_endianness((UINT4 *)pStart, outlen/4);
}
}
{
unsigned char *p2 = pStart;
todo = outlen;
while (todo != 0) {
int retval_;
retval_ = global.audio_out->WriteSound(global.audio, p2, todo);
if (retval_ < 0)
break;
p2 += retval_;
todo -= retval_;
}
}
if (todo == 0) {
*TotSamplesDone += SamplesToDo;
return (0);
} else {
errmsg(
"Error in write(audio, 0x%p, %u) = %d\nProbably disk space exhausted.\n",
pStart, outlen, retval);
return (1);
}
} else {
*TotSamplesDone += SamplesToDo;
return (0);
}
}
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