| /*************************************************************************/ |
| /* */ |
| /* Language Technologies Institute */ |
| /* Carnegie Mellon University */ |
| /* Copyright (c) 2000 */ |
| /* All Rights Reserved. */ |
| /* */ |
| /* Permission is hereby granted, free of charge, to use and distribute */ |
| /* this software and its documentation without restriction, including */ |
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| /* distribute, sublicense, and/or sell copies of this work, and to */ |
| /* permit persons to whom this work is furnished to do so, subject to */ |
| /* the following conditions: */ |
| /* 1. The code must retain the above copyright notice, this list of */ |
| /* conditions and the following disclaimer. */ |
| /* 2. Any modifications must be clearly marked as such. */ |
| /* 3. Original authors' names are not deleted. */ |
| /* 4. The authors' names are not used to endorse or promote products */ |
| /* derived from this software without specific prior written */ |
| /* permission. */ |
| /* */ |
| /* CARNEGIE MELLON UNIVERSITY AND THE CONTRIBUTORS TO THIS WORK */ |
| /* DISCLAIM ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING */ |
| /* ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO EVENT */ |
| /* SHALL CARNEGIE MELLON UNIVERSITY NOR THE CONTRIBUTORS BE LIABLE */ |
| /* FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES */ |
| /* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN */ |
| /* AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, */ |
| /* ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF */ |
| /* THIS SOFTWARE. */ |
| /* */ |
| /*************************************************************************/ |
| /* Author: Alan W Black (awb@cs.cmu.edu) */ |
| /* Date: October 2000 */ |
| /*************************************************************************/ |
| /* */ |
| /* Convertion routines for various waveform encodings */ |
| /* */ |
| /* This contains software written external to Flite */ |
| /* ulaw code came via the Edinburgh Speech Tools */ |
| /* g72x codec came from Sun Microsystems */ |
| /* */ |
| /*************************************************************************/ |
| |
| #include "g72x.h" |
| |
| /* |
| ** 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 ZEROTRAP /* turn on the trap as per the MIL-STD */ |
| #define BIAS 0x84 /* define the add-in bias for 16 bit samples */ |
| #define CLIP 32635 |
| |
| unsigned char cst_short_to_ulaw(short sample) |
| { |
| static const 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 > CLIP ) sample = CLIP; /* clip the magnitude */ |
| |
| /* Convert from 16 bit linear to ulaw. */ |
| sample = sample + BIAS; |
| exponent = exp_lut[( sample >> 7 ) & 0xFF]; |
| mantissa = ( sample >> ( exponent + 3 ) ) & 0x0F; |
| ulawbyte = ~ ( sign | ( exponent << 4 ) | mantissa ); |
| #ifdef ZEROTRAP |
| if ( ulawbyte == 0 ) ulawbyte = 0x02; /* optional CCITT trap */ |
| #endif |
| |
| return ulawbyte; |
| } |
| |
| /* |
| ** 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 |
| */ |
| |
| short cst_ulaw_to_short( unsigned char ulawbyte ) |
| { |
| static const int exp_lut[8] = { 0, 132, 396, 924, 1980, 4092, 8316, 16764 }; |
| int sign, exponent, mantissa; |
| short 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; |
| } |
| |
| |
| unsigned char *cst_g721_decode(int *actual_size,int size, |
| const unsigned char *packed_residual |
| ) |
| { |
| struct g72x_state state; |
| short sample_short; |
| unsigned char *unpacked_residual; |
| unsigned char code, xcode; |
| int ur=0; |
| int dec_bits; |
| |
| *actual_size = size*2; |
| unpacked_residual = cst_alloc(unsigned char, *actual_size); |
| g72x_init_state(&state); |
| dec_bits = 4; /* g721 4-bit encoding */ |
| |
| for (ur=0; ur <*actual_size; ur++) |
| { |
| xcode = packed_residual[ur/2]; |
| if (ur % 2 == 0) |
| code = (xcode & 0xF0) >> dec_bits; |
| else |
| code = (xcode & 0x0F); |
| sample_short = g721_decoder(code,AUDIO_ENCODING_LINEAR,&state); |
| unpacked_residual[ur] = cst_short_to_ulaw(sample_short); |
| } |
| |
| return unpacked_residual; |
| } |
| |
| unsigned char *cst_g721_encode(int *packed_size,int actual_size, |
| const unsigned char *unpacked_residual |
| ) |
| { |
| struct g72x_state state; |
| unsigned char *packed_residual; |
| unsigned char code, xcode=0; |
| int ur=0; |
| int dec_bits; |
| |
| *packed_size = (actual_size+1)/2; /* will round down to even number */ |
| packed_residual = cst_alloc(unsigned char, *packed_size); |
| |
| g72x_init_state(&state); |
| dec_bits = 4; /* g721 4-bit encoding */ |
| |
| for (ur=0; ur < actual_size; ur++) |
| { |
| code = g721_encoder((int)cst_ulaw_to_short(unpacked_residual[ur]), |
| AUDIO_ENCODING_LINEAR,&state); |
| if (ur % 2 == 0) |
| { |
| xcode = 0; |
| xcode = code << dec_bits; |
| } |
| else |
| { |
| xcode += code; |
| packed_residual[ur/2] = xcode; |
| } |
| } |
| |
| return packed_residual; |
| |
| } |
