Index: include/asterisk/alaw.h =================================================================== --- include/asterisk/alaw.h (revision 64412) +++ include/asterisk/alaw.h (working copy) @@ -23,21 +23,63 @@ #ifndef _ASTERISK_ALAW_H #define _ASTERISK_ALAW_H +/* #define G711_REDUCED_BRANCHING */ + /*! Init the ulaw conversion stuff */ /*! * To init the ulaw to slinear conversion stuff, this needs to be run. */ extern void ast_alaw_init(void); +#define AST_ALAW_BIT_LOSS 4 +#define AST_ALAW_STEP (1 << AST_ALAW_BIT_LOSS) +#define AST_ALAW_TAB_SIZE (32768 / AST_ALAW_STEP + 1) +#define AST_ALAW_SIGN_BIT 0x80 +#define AST_ALAW_AMI_MASK 0x55 + + /*! converts signed linear to mulaw */ /*! */ -extern unsigned char __ast_lin2a[8192]; +extern unsigned char __ast_lin2a[AST_ALAW_TAB_SIZE]; /*! help */ extern short __ast_alaw[256]; -#define AST_LIN2A(a) (__ast_lin2a[((unsigned short)(a)) >> 3]) +#define AST_LIN2A_LOOKUP(mag) \ + __ast_lin2a[(mag) >> AST_ALAW_BIT_LOSS] + +/*! convert signed linear sample to sign-magnitude pair for a-Law */ +static inline void ast_alaw_get_sign_mag(short sample, unsigned *sign, unsigned *mag) +{ +#if defined(G711_REDUCED_BRANCHING) + unsigned dual_mag; + + *sign = ((unsigned short)sample >> 8) & AST_ALAW_SIGN_BIT; + dual_mag = (-sample << 16) | (unsigned short)sample; + *mag = (dual_mag >> (*sign >> 3)) & 0xffffU; + *sign ^= AST_ALAW_SIGN_BIT; +#else + if (sample < 0) + { + *mag = -sample; + *sign = 0; + } + else + { + *mag = sample; + *sign = AST_ALAW_SIGN_BIT; + } +#endif /* G711_REDUCED_BRANCHING */ +} + +static inline unsigned char AST_LIN2A(short sample) +{ + unsigned mag, sign; + ast_alaw_get_sign_mag(sample, &sign, &mag); + return (sign | AST_LIN2A_LOOKUP(mag)) ^ AST_ALAW_AMI_MASK; +} + #define AST_ALAW(a) (__ast_alaw[(int)(a)]) #endif /* _ASTERISK_ALAW_H */ Index: include/asterisk/ulaw.h =================================================================== --- include/asterisk/ulaw.h (revision 64412) +++ include/asterisk/ulaw.h (working copy) @@ -23,21 +23,61 @@ #ifndef _ASTERISK_ULAW_H #define _ASTERISK_ULAW_H +/* #define G711_REDUCED_BRANCHING */ + /*! Init the ulaw conversion stuff */ /*! * To init the ulaw to slinear conversion stuff, this needs to be run. */ extern void ast_ulaw_init(void); +#define AST_ULAW_BIT_LOSS 3 +#define AST_ULAW_STEP (1 << AST_ULAW_BIT_LOSS) +#define AST_ULAW_TAB_SIZE (32768 / AST_ULAW_STEP + 1) +#define AST_ULAW_SIGN_BIT 0x80 + + /*! converts signed linear to mulaw */ /*! */ -extern unsigned char __ast_lin2mu[16384]; +extern unsigned char __ast_lin2mu[AST_ULAW_TAB_SIZE]; /*! help */ extern short __ast_mulaw[256]; -#define AST_LIN2MU(a) (__ast_lin2mu[((unsigned short)(a)) >> 2]) +#define AST_LIN2MU_LOOKUP(mag) \ + __ast_lin2mu[((mag) + AST_ULAW_STEP / 2) >> AST_ULAW_BIT_LOSS] + +/*! convert signed linear sample to sign-magnitude pair for u-Law */ +static inline void ast_ulaw_get_sign_mag(short sample, unsigned *sign, unsigned *mag) +{ +#if defined(G711_REDUCED_BRANCHING) + unsigned dual_mag; + + *sign = ((unsigned short)sample >> 8) & AST_ULAW_SIGN_BIT; + dual_mag = (-sample << 16) | (unsigned short)sample; + *mag = (dual_mag >> (*sign >> 3)) & 0xffffU; +#else + if (sample < 0) + { + *mag = -sample; + *sign = AST_ULAW_SIGN_BIT; + } + else + { + *mag = sample; + *sign = 0; + } +#endif /* G711_REDUCED_BRANCHING */ +} + +static inline unsigned char AST_LIN2MU(short sample) +{ + unsigned mag, sign; + ast_ulaw_get_sign_mag(sample, &sign, &mag); + return ~(sign | AST_LIN2MU_LOOKUP(mag)); +} + #define AST_MULAW(a) (__ast_mulaw[(a)]) #endif /* _ASTERISK_ULAW_H */ Index: alaw.c =================================================================== --- alaw.c (revision 64412) +++ alaw.c (working copy) @@ -18,7 +18,7 @@ /*! \file * - * \brief u-Law to Signed linear conversion + * \brief a-Law to Signed linear conversion * */ @@ -27,74 +27,117 @@ ASTERISK_FILE_VERSION(__FILE__, "$Revision$") #include "asterisk/alaw.h" +#include "asterisk/logger.h" -#define AMI_MASK 0x55 +#define TEST_CODING_TABLES +#define TEST_TANDEM_TRANSCODING -static inline unsigned char linear2alaw (short int linear) +static unsigned char linear2alaw(short sample, int full_coding) { - int mask; - int seg; - int pcm_val; - static int seg_end[8] = - { - 0xFF, 0x1FF, 0x3FF, 0x7FF, 0xFFF, 0x1FFF, 0x3FFF, 0x7FFF - }; - - pcm_val = linear; - if (pcm_val >= 0) - { - /* Sign (7th) bit = 1 */ - mask = AMI_MASK | 0x80; - } - else - { - /* Sign bit = 0 */ - mask = AMI_MASK; - pcm_val = -pcm_val; - } + static const unsigned exp_lut[128] = { + 1,1,2,2,3,3,3,3, + 4,4,4,4,4,4,4,4, + 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, + 7,7,7,7,7,7,7,7, + 7,7,7,7,7,7,7,7, + 7,7,7,7,7,7,7,7, + 7,7,7,7,7,7,7,7, + 7,7,7,7,7,7,7,7, + 7,7,7,7,7,7,7,7, + 7,7,7,7,7,7,7,7, + 7,7,7,7,7,7,7,7 }; + unsigned sign, exponent, mantissa, mag; + unsigned char alawbyte; - /* Convert the scaled magnitude to segment number. */ - for (seg = 0; seg < 8; seg++) - { - if (pcm_val <= seg_end[seg]) - break; - } - /* Combine the sign, segment, and quantization bits. */ - return ((seg << 4) | ((pcm_val >> ((seg) ? (seg + 3) : 4)) & 0x0F)) ^ mask; + ast_alaw_get_sign_mag(sample, &sign, &mag); + if (mag > 32767) + mag = 32767; /* clip the magnitude for -32768 */ + + exponent = exp_lut[(mag >> 8) & 0x7f]; + mantissa = (mag >> (exponent + 3)) & 0x0f; + if (mag < 0x100) + exponent = 0; + + if (full_coding) { + /* full encoding, with sign and xform */ + alawbyte = (unsigned char)(sign | (exponent << 4) | mantissa); + alawbyte ^= AST_ALAW_AMI_MASK; + } else { + /* half-cooked coding -- mantissa+exponent only (for lookup tab) */ + alawbyte = (exponent << 4) | mantissa; + } + + return alawbyte; } -/*- End of function --------------------------------------------------------*/ -static inline short int alaw2linear (unsigned char alaw) +static inline short alaw2linear(unsigned char alawbyte) { - int i; - int seg; + unsigned exponent, mantissa; + short sample; - alaw ^= AMI_MASK; - i = ((alaw & 0x0F) << 4); - seg = (((int) alaw & 0x70) >> 4); - if (seg) - i = (i + 0x100) << (seg - 1); - return (short int) ((alaw & 0x80) ? i : -i); + alawbyte ^= AST_ALAW_AMI_MASK; + exponent = (alawbyte & 0x70) >> 4; + mantissa = alawbyte & 0x0f; + sample = (mantissa << 4) + 8 /* rounding error */; + if (exponent) + sample = (sample + 0x100) << (exponent - 1); + if (!(alawbyte & 0x80)) + sample = -sample; + return sample; } -unsigned char __ast_lin2a[8192]; +unsigned char __ast_lin2a[AST_ALAW_TAB_SIZE]; short __ast_alaw[256]; void ast_alaw_init(void) { int i; + /* - * Set up mu-law conversion table + * Set up a-law conversion table */ - for(i = 0;i < 256;i++) - { - __ast_alaw[i] = alaw2linear(i); - } - /* set up the reverse (mu-law) conversion table */ - for(i = -32768; i < 32768; i++) - { - __ast_lin2a[((unsigned short)i) >> 3] = linear2alaw(i); - } + for(i = 0; i < 256; i++) { + __ast_alaw[i] = alaw2linear(i); + } + /* set up the reverse (a-law) conversion table */ + for(i = 0; i <= 32768; i += AST_ALAW_STEP) { + AST_LIN2A_LOOKUP(i) = linear2alaw(i, 0 /* half-cooked */); + } +#ifdef TEST_CODING_TABLES + for (i = -32768; i < 32768; ++i) { + unsigned char e1 = linear2alaw(i, 1); + short d1 = alaw2linear(e1); + unsigned char e2 = AST_LIN2A(i); + short d2 = alaw2linear(e2); + short d3 = AST_ALAW(e1); + + if (e1 != e2 || d1 != d3 || d2 != d3) { + ast_log(LOG_WARNING, "a-Law coding tables test failed on %d: e1=%u, e2=%u, d1=%d, d2=%d\n", + i, (unsigned)e1, (unsigned)e2, (int)d1, (int)d2); + } + } +#endif /* TEST_CODING_TABLES */ + +#ifdef TEST_TANDEM_TRANSCODING + /* tandem transcoding test */ + for (i = -32768; i < 32768; ++i) { + unsigned char e1 = AST_LIN2A(i); + short d1 = AST_ALAW(e1); + unsigned char e2 = AST_LIN2A(d1); + short d2 = AST_ALAW(e2); + unsigned char e3 = AST_LIN2A(d2); + short d3 = AST_ALAW(e3); + + if (e1 != e2 || e2 != e3 || d1 != d2 || d2 != d3) { + ast_log(LOG_WARNING, "a-Law tandem transcoding test failed on %d: e1=%u, e2=%u, d1=%d, d2=%d, d3=%d\n", + i, (unsigned)e1, (unsigned)e2, (int)d1, (int)d2, (int)d3); + } + } +#endif /* TEST_TANDEM_TRANSCODING */ } - Index: ulaw.c =================================================================== --- ulaw.c (revision 64412) +++ ulaw.c (working copy) @@ -27,18 +27,30 @@ ASTERISK_FILE_VERSION(__FILE__, "$Revision$") #include "asterisk/ulaw.h" +#include "asterisk/logger.h" +#define TEST_CODING_TABLES +#define TEST_TANDEM_TRANSCODING + +#if 0 +/* ZEROTRAP is the military recommendation to improve the encryption + * of u-Law traffic. It is irrelevant with modern encryption systems + * like AES, and will simply degrade the signal quality. + * ZEROTRAP is not implemented in AST_LIN2MU and so the coding table + * tests will fail if you use it */ #define ZEROTRAP /*!< turn on the trap as per the MIL-STD */ +#endif + #define BIAS 0x84 /*!< define the add-in bias for 16 bit samples */ #define CLIP 32635 -unsigned char __ast_lin2mu[16384]; +unsigned char __ast_lin2mu[AST_ULAW_TAB_SIZE]; short __ast_mulaw[256]; -static unsigned char linear2ulaw(short sample) +static unsigned char linear2ulaw(short sample, int full_coding) { - static int exp_lut[256] = { + static const unsigned 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, @@ -55,51 +67,101 @@ 7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7, 7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7, 7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7 }; - int sign, exponent, mantissa; + unsigned sign, exponent, mantissa, mag; 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 */ + ast_ulaw_get_sign_mag(sample, &sign, &mag); + if (mag > CLIP) + mag = 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); + mag += BIAS; + exponent = exp_lut[(mag >> 7) & 0xFF]; + mantissa = (mag >> (exponent + 3)) & 0x0F; + + if (full_coding) { + /* full encoding, with sign and xform */ + ulawbyte = ~(sign | (exponent << 4) | mantissa); #ifdef ZEROTRAP - if (ulawbyte == 0) - ulawbyte = 0x02; /* optional CCITT trap */ + if (ulawbyte == 0) + ulawbyte = 0x02; /* optional CCITT trap */ #endif + } else { + /* half-cooked coding -- mantissa+exponent only (for lookup tab) */ + ulawbyte = (exponent << 4) | mantissa; + } return ulawbyte; } +static inline short ulaw2linear(unsigned char ulawbyte) +{ + unsigned exponent, mantissa; + short sample; + static const short etab[]={0,132,396,924,1980,4092,8316,16764}; + + ulawbyte = ~ulawbyte; + exponent = (ulawbyte & 0x70) >> 4; + mantissa = ulawbyte & 0x0f; + sample = mantissa << (exponent + 3); + sample += etab[exponent]; + if (ulawbyte & 0x80) + sample = -sample; + return sample; +} + /*! * \brief Set up mu-law conversion table */ void ast_ulaw_init(void) { int i; - for(i = 0;i < 256;i++) { - short mu,e,f,y; - static short etab[]={0,132,396,924,1980,4092,8316,16764}; - mu = 255-i; - e = (mu & 0x70)/16; - f = mu & 0x0f; - y = f * (1 << (e + 3)); - y += etab[e]; - if (mu & 0x80) y = -y; - __ast_mulaw[i] = y; + /* + * Set up mu-law conversion table + */ + for(i = 0; i < 256; i++) { + __ast_mulaw[i] = ulaw2linear(i); } /* set up the reverse (mu-law) conversion table */ - for(i = -32768; i < 32768; i++) { - __ast_lin2mu[((unsigned short)i) >> 2] = linear2ulaw(i); + for(i = 0; i <= 32768; i += AST_ULAW_STEP) { + AST_LIN2MU_LOOKUP(i) = linear2ulaw(i, 0 /* half-cooked */); } +#ifdef TEST_CODING_TABLES + for (i = -32768; i < 32768; ++i) { + unsigned char e1 = linear2ulaw(i, 1); + short d1 = ulaw2linear(e1); + unsigned char e2 = AST_LIN2MU(i); + short d2 = ulaw2linear(e2); + short d3 = AST_MULAW(e1); + + if (e1 != e2 || d1 != d3 || d2 != d3) { + ast_log(LOG_WARNING, "u-Law coding tables test failed on %d: e1=%u, e2=%u, d1=%d, d2=%d\n", + i, (unsigned)e1, (unsigned)e2, (int)d1, (int)d2); + } + } +#endif /* TEST_CODING_TABLES */ + +#ifdef TEST_TANDEM_TRANSCODING + /* tandem transcoding test */ + for (i = -32768; i < 32768; ++i) { + unsigned char e1 = AST_LIN2MU(i); + short d1 = AST_MULAW(e1); + unsigned char e2 = AST_LIN2MU(d1); + short d2 = AST_MULAW(e2); + unsigned char e3 = AST_LIN2MU(d2); + short d3 = AST_MULAW(e3); + + if (i < 0 && e1 == 0x7f && e2 == 0xff && e3 == 0xff) + continue; /* known and normal negative 0 case */ + + if (e1 != e2 || e2 != e3 || d1 != d2 || d2 != d3) { + ast_log(LOG_WARNING, "u-Law tandem transcoding test failed on %d: e1=%u, e2=%u, d1=%d, d2=%d, d3=%d\n", + i, (unsigned)e1, (unsigned)e2, (int)d1, (int)d2, (int)d3); + } + } +#endif /* TEST_TANDEM_TRANSCODING */ }