| /* |
| ** Copyright (C) 1999-2011 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 */ |
| |