/*
* TwoLAME: an optimized MPEG Audio Layer Two encoder
*
* Copyright (C) 2001-2004 Michael Cheng
* Copyright (C) 2004-2006 The TwoLAME Project
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
* $Id$
*
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "audio_wave.h"
/*****************************************************************************
*
* Routines to determine byte order (of this machine) and swap bytes
*
*****************************************************************************/
enum byte_order { order_unknown, order_bigEndian, order_littleEndian };
static enum byte_order DetermineByteOrder(void)
{
char s[sizeof(long) + 1];
union {
long longval;
char charval[sizeof(long)];
} probe;
probe.longval = 0x41424344L; /* ABCD in ASCII */
strncpy(s, probe.charval, sizeof(long));
s[sizeof(long)] = '\0';
/* printf("byte order is %s\n", s ); */
if (strcmp(s, "ABCD") == 0)
return order_bigEndian;
else if (strcmp(s, "DCBA") == 0)
return order_littleEndian;
else
return order_unknown;
}
static void SwapBytesInWords(short *loc, int words)
{
int i;
short thisval;
char *dst, *src;
src = (char *) &thisval;
for (i = 0; i < words; i++) {
thisval = *loc;
dst = (char *) loc++;
dst[0] = src[1];
dst[1] = src[0];
}
}
/*****************************************************************************
*
* Read in specified number of samples
*
*****************************************************************************/
int wave_get_samples(wave_info_t * wave_info, short int pcm[], int numSamples)
{
int samples_read;
FILE *file = wave_info->soundfile;
samples_read = fread(pcm, sizeof(short int), numSamples, file);
if (wave_info->byteswap) {
SwapBytesInWords(pcm, samples_read);
}
return (samples_read / wave_info->channels);
}
/*****************************************************************************
*
* parse the wave header.
* returns NULL if not open failed
* returns a wave_info_t * if wave header successfully parsed.
* needs to fill in : samplerate + channels
*
* POST: wave_info->soundfile is set to be at the start of the
* PCM audio data
*
*****************************************************************************/
wave_info_t *wave_init(char *inPath)
{
unsigned char wave_header_buffer[40]; // HH fixed
int wave_header_read = 0;
int wave_header_stereo = -1;
int wave_header_16bit = -1;
unsigned long samplerate;
enum byte_order NativeByteOrder = order_unknown;
wave_info_t *wave_info = NULL;
FILE *file;
if ((file = fopen(inPath, "rb")) == NULL) {
printf("WAV: cannot open input file: %s\n", inPath);
return (NULL);
}
/************** WAVE ************************/
/* Nick Burch <The_Leveller@newmail.net> */
/********************************************/
/* Wave File Headers: (Dec) */
/* 8-11 = "WAVE" */
/* 22 = Stereo / Mono */
/* 01 = mono, 02 = stereo */
/* 24 = Sampling Frequency */
/* 32 = Data Rate */
/* 01 = x1 (8bit Mono) */
/* 02 = x2 (8bit Stereo or */
/* 16bit Mono) */
/* 04 = x4 (16bit Stereo) */
/********************************************/
fseek(file, 0, SEEK_SET);
fread(wave_header_buffer, 1, 40, file);
if (wave_header_buffer[8] == 'W' && wave_header_buffer[9] == 'A'
&& wave_header_buffer[10] == 'V' && wave_header_buffer[11] == 'E') {
printf("Parsing Wave File Header\n");
if (NativeByteOrder == order_unknown) {
NativeByteOrder = DetermineByteOrder();
if (NativeByteOrder == order_unknown) {
printf("byte order not determined\n");
fclose(file);
return (NULL);
}
}
if (NativeByteOrder == order_littleEndian) {
samplerate = *(unsigned long *) (&wave_header_buffer[24]);
} else {
samplerate = wave_header_buffer[27] +
(wave_header_buffer[26] << 8) +
(wave_header_buffer[25] << 16) + (wave_header_buffer[24] << 24);
}
/* Wave File */
wave_header_read = 1;
switch (samplerate) {
case 44100:
case 48000:
case 32000:
case 24000:
case 22050:
case 16000:
printf(">>> %ld Hz sampling freq selected\n", samplerate);
break;
default:
/* Unknown Unsupported Frequency */
printf(">>> Unknown samp freq %ld Hz in Wave Header\n", samplerate);
printf(">>> Default 44.1 kHz samp freq selected\n");
samplerate = 44100;
break;
}
if ((long) wave_header_buffer[22] == 1) {
printf(">>> Input Wave File is Mono\n");
wave_header_stereo = 0;
}
if ((long) wave_header_buffer[22] == 2) {
printf(">>> Input Wave File is Stereo\n");
wave_header_stereo = 1;
}
if ((long) wave_header_buffer[32] == 1) {
printf(">>> Input Wave File is 8 Bit\n");
wave_header_16bit = 0;
printf("Input File must be 16 Bit! Please Re-sample");
fclose(file);
return (NULL);
}
if ((long) wave_header_buffer[32] == 2) {
if (wave_header_stereo == 1) {
printf(">>> Input Wave File is 8 Bit\n");
wave_header_16bit = 0;
printf("Input File must be 16 Bit! Please Re-sample");
fclose(file);
return (NULL);
} else {
/* printf(">>> Input Wave File is 16 Bit\n" ); */
wave_header_16bit = 1;
}
}
if ((long) wave_header_buffer[32] == 4) {
/* printf(">>> Input Wave File is 16 Bit\n" ); */
wave_header_16bit = 1;
}
/* should probably use the wave header to determine size here FIXME MFC Feb 2003 */
if (fseek(file, 44, SEEK_SET) != 0) {
/* there's a way of calculating the size of the wave header. i'll just jump 44 to start
with */
printf("Could not seek to PCM sound data in \"%s\".\n", inPath);
fclose(file);
return (NULL);
}
// Successfully processed the wave header
wave_info = (wave_info_t *) calloc(1, sizeof(wave_info_t));
wave_info->soundfile = file;
if (wave_header_stereo == 1)
wave_info->channels = 2;
else
wave_info->channels = 1;
wave_info->samplerate = samplerate;
// UNKNOWN. But we really should be able to work
// it out. FIX THIS. MFC May03.
wave_info->num_samples = -1;
// Enable byte swap for big endian machines
if (NativeByteOrder == order_bigEndian)
wave_info->byteswap = 1;
else
wave_info->byteswap = 0;
return (wave_info);
}
// not a wave file
fclose(file);
return (NULL);
}
/* vim:ts=4:sw=4:nowrap: */