third_party_libsnd/tests/ulaw_test.c
Erik de Castro Lopo 9fa6c74223 Whitespace.
2012-03-18 12:06:16 +11:00

258 lines
7.0 KiB
C

/*
** Copyright (C) 1999-2012 Erik de Castro Lopo <erikd@mega-nerd.com>
**
** 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 program 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 General Public License for more details.
**
** You should have received a copy of the GNU General Public License
** along with this program; if not, write to the Free Software
** Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*/
#include "sfconfig.h"
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#if HAVE_UNISTD_H
#include <unistd.h>
#endif
#include <sndfile.h>
#include "utils.h"
#define BUFFER_SIZE (65536)
static unsigned char ulaw_encode (int sample) ;
static int ulaw_decode (unsigned int ulawbyte) ;
static short short_buffer [BUFFER_SIZE] ;
static unsigned char ulaw_buffer [BUFFER_SIZE] ;
int
main (void)
{ SNDFILE *file ;
SF_INFO sfinfo ;
const char *filename ;
int k ;
print_test_name ("ulaw_test", "encoder") ;
filename = "test.raw" ;
sf_info_setup (&sfinfo, SF_FORMAT_RAW | SF_FORMAT_ULAW, 44100, 1) ;
if ((file = sf_open (filename, SFM_WRITE, &sfinfo)) == NULL)
{ printf ("sf_open_write failed with error : ") ;
fflush (stdout) ;
puts (sf_strerror (NULL)) ;
exit (1) ;
} ;
/* Generate a file containing all possible 16 bit sample values
** and write it to disk as ulaw encoded.frames.
*/
for (k = 0 ; k < 0x10000 ; k++)
short_buffer [k] = k & 0xFFFF ;
sf_write_short (file, short_buffer, BUFFER_SIZE) ;
sf_close (file) ;
/* Now open that file and compare the ulaw encoded sample values
** with what they should be.
*/
if ((file = sf_open (filename, SFM_READ, &sfinfo)) == NULL)
{ printf ("sf_open_write failed with error : ") ;
puts (sf_strerror (NULL)) ;
exit (1) ;
} ;
check_log_buffer_or_die (file, __LINE__) ;
if (sf_read_raw (file, ulaw_buffer, BUFFER_SIZE) != BUFFER_SIZE)
{ printf ("sf_read_raw : ") ;
puts (sf_strerror (file)) ;
exit (1) ;
} ;
for (k = 0 ; k < 0x10000 ; k++)
if (ulaw_encode (short_buffer [k]) != ulaw_buffer [k])
{ printf ("Encoder error : sample #%d (0x%02X should be 0x%02X)\n", k, ulaw_buffer [k], ulaw_encode (short_buffer [k])) ;
exit (1) ;
} ;
sf_close (file) ;
puts ("ok") ;
print_test_name ("ulaw_test", "decoder") ;
/* Now generate a file containing all possible 8 bit encoded
** sample values and write it to disk as ulaw encoded.frames.
*/
if (! (file = sf_open (filename, SFM_WRITE, &sfinfo)))
{ printf ("sf_open_write failed with error : ") ;
puts (sf_strerror (NULL)) ;
exit (1) ;
} ;
for (k = 0 ; k < 256 ; k++)
ulaw_buffer [k] = k & 0xFF ;
sf_write_raw (file, ulaw_buffer, 256) ;
sf_close (file) ;
/* Now open that file and compare the ulaw decoded sample values
** with what they should be.
*/
if (! (file = sf_open (filename, SFM_READ, &sfinfo)))
{ printf ("sf_open_write failed with error : ") ;
puts (sf_strerror (NULL)) ;
exit (1) ;
} ;
check_log_buffer_or_die (file, __LINE__) ;
if (sf_read_short (file, short_buffer, 256) != 256)
{ printf ("sf_read_short : ") ;
puts (sf_strerror (file)) ;
exit (1) ;
} ;
for (k = 0 ; k < 256 ; k++)
if (short_buffer [k] != ulaw_decode (ulaw_buffer [k]))
{ printf ("Decoder error : sample #%d (0x%04X should be 0x%04X)\n", k, short_buffer [k], ulaw_decode (ulaw_buffer [k])) ;
exit (1) ;
} ;
sf_close (file) ;
puts ("ok") ;
unlink (filename) ;
return 0 ;
} /* main */
/*=================================================================================
** The following routines came from the sox-12.15 (Sound eXcahcnge) distribution.
**
** This code is not compiled into libsndfile. It is only used to test the
** libsndfile lookup tables for correctness.
**
** I have included the original authors comments.
*/
/*
** This routine converts from linear to ulaw.
**
** Craig Reese: IDA/Supercomputing Research Center
** Joe Campbell: Department of Defense
** 29 September 1989
**
** References:
** 1) CCITT Recommendation G.711 (very difficult to follow)
** 2) "A New Digital Technique for Implementation of Any
** Continuous PCM Companding Law," Villeret, Michel,
** et al. 1973 IEEE Int. Conf. on Communications, Vol 1,
** 1973, pg. 11.12-11.17
** 3) MIL-STD-188-113,"Interoperability and Performance Standards
** for Analog-to_Digital Conversion Techniques,"
** 17 February 1987
**
** Input: Signed 16 bit linear sample
** Output: 8 bit ulaw sample
*/
#define uBIAS 0x84 /* define the add-in bias for 16 bit.frames */
#define uCLIP 32635
static
unsigned char ulaw_encode (int sample)
{ static int exp_lut [256] =
{ 0, 0, 1, 1, 2, 2, 2, 2, 3, 3, 3, 3, 3, 3, 3, 3,
4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4,
5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5,
5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5,
6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6,
6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6,
6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6,
6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6,
7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7
} ;
int sign, exponent, mantissa ;
unsigned char ulawbyte ;
/* Get the sample into sign-magnitude. */
sign = (sample >> 8) & 0x80 ; /* set aside the sign */
if (sign != 0)
sample = -sample ; /* get magnitude */
if (sample > uCLIP)
sample = uCLIP ; /* clip the magnitude */
/* Convert from 16 bit linear to ulaw. */
sample = sample + uBIAS ;
exponent = exp_lut [(sample >> 7) & 0xFF] ;
mantissa = (sample >> (exponent + 3)) & 0x0F ;
ulawbyte = ~ (sign | (exponent << 4) | mantissa) ;
return ulawbyte ;
} /* ulaw_encode */
/*
** This routine converts from ulaw to 16 bit linear.
**
** Craig Reese: IDA/Supercomputing Research Center
** 29 September 1989
**
** References:
** 1) CCITT Recommendation G.711 (very difficult to follow)
** 2) MIL-STD-188-113,"Interoperability and Performance Standards
** for Analog-to_Digital Conversion Techniques,"
** 17 February 1987
**
** Input: 8 bit ulaw sample
** Output: signed 16 bit linear sample
*/
static
int ulaw_decode (unsigned int ulawbyte)
{ static int exp_lut [8] = { 0, 132, 396, 924, 1980, 4092, 8316, 16764 } ;
int sign, exponent, mantissa, sample ;
ulawbyte = ~ ulawbyte ;
sign = (ulawbyte & 0x80) ;
exponent = (ulawbyte >> 4) & 0x07 ;
mantissa = ulawbyte & 0x0F ;
sample = exp_lut [exponent] + (mantissa << (exponent + 3)) ;
if (sign != 0)
sample = -sample ;
return sample ;
} /* ulaw_decode */