Index: alaw.c =================================================================== --- alaw.c (revision 44743) +++ alaw.c (working copy) @@ -18,7 +18,7 @@ /*! \file * - * \brief u-Law to Signed linear conversion + * \brief a-Law to Signed linear conversion * */ @@ -27,54 +27,66 @@ ASTERISK_FILE_VERSION(__FILE__, "$Revision$") #include "asterisk/alaw.h" +#include "asterisk/logger.h" #define AMI_MASK 0x55 -static inline unsigned char linear2alaw (short int linear) +static inline unsigned char linear2alaw(short sample) { - 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; + if (sample < 0) { + mag = -sample; + sign = 0; + } else { + mag = sample; + sign = 0x80; + } + 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; + alawbyte = (unsigned char)(sign | (exponent << 4) | mantissa); + alawbyte ^= AMI_MASK; + + 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 ^= 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]; @@ -84,17 +96,45 @@ { 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++) - { + for(i = 0;i < 256;i++) { + __ast_alaw[i] = alaw2linear(i); + } + /* set up the reverse (a-law) conversion table */ + for(i = -32764; i < 32768; i += 8) { __ast_lin2a[((unsigned short)i) >> 3] = linear2alaw(i); - } + } +#ifdef TEST_CODING_TABLES + for (i = -32768; i < 32768; ++i) { + unsigned char e1 = linear2alaw(i); + 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_ERROR, "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_ERROR, "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 44743) +++ ulaw.c (working copy) @@ -27,6 +27,7 @@ ASTERISK_FILE_VERSION(__FILE__, "$Revision$") #include "asterisk/ulaw.h" +#include "asterisk/logger.h" #define ZEROTRAP /*!< turn on the trap as per the MIL-STD */ #define BIAS 0x84 /*!< define the add-in bias for 16 bit samples */ @@ -38,7 +39,7 @@ static unsigned char linear2ulaw(short sample) { - 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, @@ -55,20 +56,24 @@ 7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7, 7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7, 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 */ + if (sample < 0) { + mag = -sample; /* get magnitude */ + sign = 0x80; + } else { + mag = sample; + sign = 0; + } + 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; + mag += BIAS; + exponent = exp_lut[(mag >> 7) & 0xFF]; + mantissa = (mag >> (exponent + 3)) & 0x0F; ulawbyte = ~(sign | (exponent << 4) | mantissa); #ifdef ZEROTRAP if (ulawbyte == 0) @@ -78,6 +83,22 @@ 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 */ @@ -85,21 +106,46 @@ { 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; + __ast_mulaw[i] = ulaw2linear(i); } /* set up the reverse (mu-law) conversion table */ - for(i = -32768; i < 32768; i++) { + for(i = -32766; i < 32768; i += 4) { __ast_lin2mu[((unsigned short)i) >> 2] = linear2ulaw(i); } +#ifdef TEST_CODING_TABLES + for (i = -32768; i < 32768; ++i) { + unsigned char e1 = linear2ulaw(i); + 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_ERROR, "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_ERROR, "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 */ }