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/***************************************************************************
* __________ __ ___.
* Open \______ \ ____ ____ | | _\_ |__ _______ ___
* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
* \/ \/ \/ \/ \/
* $Id$
*
* Copyright (C) 2004 by Jörg Hohensohn
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
* KIND, either express or implied.
*
* Details at http://www.rockbox.org/twiki/bin/view/Main/VoiceBuilding
*
****************************************************************************/
#include <stdio.h> /* for file I/O */
#include <stdlib.h> /* for malloc */
#include "wavtrim.h"
/* place a 32 bit value into memory, little endian */
void Write32(unsigned char* pByte, unsigned long value)
{
pByte[0] = (unsigned char)value;
pByte[1] = (unsigned char)(value >> 8);
pByte[2] = (unsigned char)(value >> 16);
pByte[3] = (unsigned char)(value >> 24) ;
}
/* read a 32 bit value from memory, little endian */
unsigned long Read32(unsigned char* pByte)
{
unsigned long value = 0;
value |= (unsigned long)pByte[0];
value |= (unsigned long)pByte[1] << 8;
value |= (unsigned long)pByte[2] << 16;
value |= (unsigned long)pByte[3] << 24;
return value;
}
/* place a 16 bit value into memory, little endian */
void Write16(unsigned char* pByte, unsigned short value)
{
pByte[0] = (unsigned char)value;
pByte[1] = (unsigned char)(value >> 8);
}
/* read a 16 bit value from memory, little endian */
unsigned long Read16(unsigned char* pByte)
{
unsigned short value = 0;
value |= (unsigned short)pByte[0];
value |= (unsigned short)pByte[1] << 8;
return value;
}
int wavtrim(char * filename, int maxsilence ,char* errstring,int errsize)
{
FILE* pFile;
long lFileSize, lGot;
unsigned char* pBuf;
int bps; /* byte per sample */
int sps; /* samples per second */
int datapos; /* where the payload starts */
int datalen; /* Length of the data chunk */
unsigned char *databuf; /* Pointer to the data chunk payload */
int skip_head, skip_tail, pad_head, pad_tail;
int i;
int max_silence = maxsilence;
signed char sample8;
short sample16;
pFile = fopen(filename, "rb");
if (pFile == NULL)
{
snprintf(errstring,errsize,"Error opening file %s for reading\n", filename);
return -1;
}
fseek(pFile, 0, SEEK_END);
lFileSize = ftell(pFile);
fseek(pFile, 0, SEEK_SET);
pBuf = malloc(lFileSize);
if (pBuf == NULL)
{
snprintf(errstring,errsize,"Out of memory to allocate %ld bytes for file.\n", lFileSize);
fclose(pFile);
return -1;
}
lGot = fread(pBuf, 1, lFileSize, pFile);
fclose(pFile);
if (lGot != lFileSize)
{
snprintf(errstring,errsize,"File read error, got only %ld bytes out of %ld.\n", lGot, lFileSize);
free(pBuf);
return -1;
}
bps = Read16(pBuf + 32);
datapos = 28 + Read16(pBuf + 16);
databuf = &pBuf[datapos];
if (Read32(pBuf) != 0x46464952 /* "RIFF" */
|| Read32(pBuf+8) != 0x45564157 /* "WAVE" */
|| Read32(pBuf+12) != 0x20746d66 /* "fmt " */
|| Read32(pBuf+datapos-8) != 0x61746164) /* "data" */
{
snprintf(errstring,errsize,"No valid input WAV file?\n");
free(pBuf);
return -1;
}
datalen = Read32(pBuf+datapos-4);
skip_head = skip_tail = 0;
sps = Read32(pBuf + 24);
pad_head = sps * 10 / 1000; /* 10 ms */
pad_tail = sps * 10 / 1000; /* 10 ms */
if (bps == 1) /* 8 bit samples */
{
max_silence >>= 8;
/* clip the start */
for (i=0; i<datalen; i++)
{
sample8 = databuf[i] - 0x80;
if (abs(sample8) > max_silence)
break;
}
skip_head = i;
skip_head = (skip_head > pad_head) ? skip_head - pad_head : 0;
/* clip the end */
for (i=datalen-1; i>skip_head; i--)
{
sample8 = databuf[i] - 0x80;
if (abs(sample8) > max_silence)
break;
}
skip_tail = datalen - 1 - i;
skip_tail = (skip_tail > pad_tail) ? skip_tail - pad_tail : 0;
}
else if (bps == 2) /* 16 bit samples */
{
/* clip the start */
for (i=0; i<datalen; i+=2)
{
sample16 = *(short *)(databuf + i);
if (abs(sample16) > max_silence)
break;
}
skip_head = i;
skip_head = (skip_head > 2 * pad_head) ?
skip_head - 2 * pad_head : 0;
/* clip the end */
for (i=datalen-2; i>skip_head; i-=2)
{
sample16 = *(short *)(databuf + i);
if (abs(sample16) > max_silence)
break;
}
skip_tail = datalen - 2 - i;
skip_tail = (skip_tail > 2 * pad_tail) ?
skip_tail - 2 * pad_tail : 0;
}
/* update the size in the headers */
Write32(pBuf+4, Read32(pBuf+4) - skip_head - skip_tail);
Write32(pBuf+datapos-4, datalen - skip_head - skip_tail);
pFile = fopen(filename, "wb");
if (pFile == NULL)
{
snprintf(errstring,errsize,"Error opening file %s for writing\n",filename);
return -1;
}
/* write the new file */
fwrite(pBuf, 1, datapos, pFile); /* write header */
fwrite(pBuf + datapos + skip_head, 1, datalen - skip_head - skip_tail, pFile);
fclose(pFile);
free(pBuf);
return 0;
}
#ifndef RBUTIL
int main (int argc, char** argv)
{
int max_silence = 0;
char errbuffer[255];
int ret=0;
if (argc < 2)
{
printf("wavtrim removes silence at the begin and end of a WAV file.\n");
printf("usage: wavtrim <filename.wav> [<max_silence>]\n");
return 0;
}
if (argc == 3)
{
max_silence = atoi(argv[2]);
}
ret = wavtrim(argv[1],max_silence,errbuffer,255 );
if( ret< 0)
{
printf(errbuffer);
}
return ret;
}
#endif
/*
RIFF Chunk (12 bytes in length total)
0 - 3 "RIFF" (ASCII Characters)
4 - 7 Total Length Of Package To Follow (Binary, little endian)
8 - 11 "WAVE" (ASCII Characters)
FORMAT Chunk (24 or 26 bytes in length total) Byte Number
12 - 15 "fmt_" (ASCII Characters)
16 - 19 Length Of FORMAT Chunk (Binary, 0x10 or 0x12 seen)
20 - 21 Always 0x01
22 - 23 Channel Numbers (Always 0x01=Mono, 0x02=Stereo)
24 - 27 Sample Rate (Binary, in Hz)
28 - 31 Bytes Per Second
32 - 33 Bytes Per Sample: 1=8 bit Mono, 2=8 bit Stereo or 16 bit Mono, 4=16 bit Stereo
34 - 35 Bits Per Sample
DATA Chunk Byte Number
36 - 39 "data" (ASCII Characters)
40 - 43 Length Of Data To Follow
44 - end
Data (Samples)
*/
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