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Diffstat (limited to 'src/audio/g72x.h')
| -rw-r--r-- | src/audio/g72x.h | 151 |
1 files changed, 151 insertions, 0 deletions
diff --git a/src/audio/g72x.h b/src/audio/g72x.h new file mode 100644 index 0000000..85201c3 --- /dev/null +++ b/src/audio/g72x.h @@ -0,0 +1,151 @@ +/* + * This source code is a product of Sun Microsystems, Inc. and is provided + * for unrestricted use. Users may copy or modify this source code without + * charge. + * + * SUN SOURCE CODE IS PROVIDED AS IS WITH NO WARRANTIES OF ANY KIND INCLUDING + * THE WARRANTIES OF DESIGN, MERCHANTIBILITY AND FITNESS FOR A PARTICULAR + * PURPOSE, OR ARISING FROM A COURSE OF DEALING, USAGE OR TRADE PRACTICE. + * + * Sun source code is provided with no support and without any obligation on + * the part of Sun Microsystems, Inc. to assist in its use, correction, + * modification or enhancement. + * + * SUN MICROSYSTEMS, INC. SHALL HAVE NO LIABILITY WITH RESPECT TO THE + * INFRINGEMENT OF COPYRIGHTS, TRADE SECRETS OR ANY PATENTS BY THIS SOFTWARE + * OR ANY PART THEREOF. + * + * In no event will Sun Microsystems, Inc. be liable for any lost revenue + * or profits or other special, indirect and consequential damages, even if + * Sun has been advised of the possibility of such damages. + * + * Sun Microsystems, Inc. + * 2550 Garcia Avenue + * Mountain View, California 94043 + */ + +/* + * g72x.h + * + * Header file for CCITT conversion routines. + * + */ +#ifndef _G72X_H +#define _G72X_H + +#define AUDIO_ENCODING_ULAW (1) /* ISDN u-law */ +#define AUDIO_ENCODING_ALAW (2) /* ISDN A-law */ +#define AUDIO_ENCODING_LINEAR (3) /* PCM 2's-complement (0-center) */ + +/* + * The following is the definition of the state structure + * used by the G.721/G.723 encoder and decoder to preserve their internal + * state between successive calls. The meanings of the majority + * of the state structure fields are explained in detail in the + * CCITT Recommendation G.721. The field names are essentially indentical + * to variable names in the bit level description of the coding algorithm + * included in this Recommendation. + */ +struct g72x_state { + long yl; /* Locked or steady state step size multiplier. */ + short yu; /* Unlocked or non-steady state step size multiplier. */ + short dms; /* Short term energy estimate. */ + short dml; /* Long term energy estimate. */ + short ap; /* Linear weighting coefficient of 'yl' and 'yu'. */ + + short a[2]; /* Coefficients of pole portion of prediction filter. */ + short b[6]; /* Coefficients of zero portion of prediction filter. */ + short pk[2]; /* + * Signs of previous two samples of a partially + * reconstructed signal. + */ + short dq[6]; /* + * Previous 6 samples of the quantized difference + * signal represented in an internal floating point + * format. + */ + short sr[2]; /* + * Previous 2 samples of the quantized difference + * signal represented in an internal floating point + * format. + */ + char td; /* delayed tone detect, new in 1988 version */ +}; + +int predictor_zero(struct g72x_state *state_ptr); +int predictor_pole(struct g72x_state *state_ptr); +int step_size(struct g72x_state *state_ptr); + +int quantize( + int d, /* Raw difference signal sample */ + int y, /* Step size multiplier */ + short *table, /* quantization table */ + int size); /* table size of short integers */ + +int reconstruct( + int sign, /* 0 for non-negative value */ + int dqln, /* G.72x codeword */ + int y); /* Step size multiplier */ + +void update( + int code_size, /* distinguish 723_40 with others */ + int y, /* quantizer step size */ + int wi, /* scale factor multiplier */ + int fi, /* for long/short term energies */ + int dq, /* quantized prediction difference */ + int sr, /* reconstructed signal */ + int dqsez, /* difference from 2-pole predictor */ + struct g72x_state *state_ptr); + +int tandem_adjust_alaw( + int sr, /* decoder output linear PCM sample */ + int se, /* predictor estimate sample */ + int y, /* quantizer step size */ + int i, /* decoder input code */ + int sign, + short *qtab); + +int +tandem_adjust_ulaw( + int sr, /* decoder output linear PCM sample */ + int se, /* predictor estimate sample */ + int y, /* quantizer step size */ + int i, /* decoder input code */ + int sign, + short *qtab); + +void g72x_init_state(struct g72x_state *); +int g721_encoder( + int sample, + int in_coding, + struct g72x_state *state_ptr); +int g721_decoder( + int code, + int out_coding, + struct g72x_state *state_ptr); +int g723_16_encoder( + int sample, + int in_coding, + struct g72x_state *state_ptr); +int g723_16_decoder( + int code, + int out_coding, + struct g72x_state *state_ptr); +int g723_24_encoder( + int sample, + int in_coding, + struct g72x_state *state_ptr); +int g723_24_decoder( + int code, + int out_coding, + struct g72x_state *state_ptr); +int g723_40_encoder( + int sample, + int in_coding, + struct g72x_state *state_ptr); +int g723_40_decoder( + int code, + int out_coding, + struct g72x_state *state_ptr); + +#endif /* !_G72X_H */ |