From 5da86a52903cf76faea421421e0257ed32564e92 Mon Sep 17 00:00:00 2001 From: Mark Spencer Date: Sat, 10 Nov 2001 20:31:39 +0000 Subject: Version 0.1.10 from FTP git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@388 65c4cc65-6c06-0410-ace0-fbb531ad65f3 --- channels/gentone-ulaw.c | 157 ++++++++++++++++++++++++++++++++++++++++++++++++ channels/gentone.c | 4 +- 2 files changed, 159 insertions(+), 2 deletions(-) create mode 100755 channels/gentone-ulaw.c (limited to 'channels') diff --git a/channels/gentone-ulaw.c b/channels/gentone-ulaw.c new file mode 100755 index 000000000..b290d76c7 --- /dev/null +++ b/channels/gentone-ulaw.c @@ -0,0 +1,157 @@ +/* Generate a header file for a particular + single or double frequency */ + +#include +#include +#include +#include +#include +#define CLIP 32635 +#define BIAS 0x84 +static float loudness=16384.0; + +static int calc_samples(int freq) +{ + int x, samples; + /* Calculate the number of samples at 8000hz sampling + we need to have this wave form */ + samples = 8000; + /* Take out common 2's up to six times */ + for (x=0;x<6;x++) + if (!(freq % 2)) { + freq /= 2; + samples /= 2; + } + /* Take out common 5's (up to three times */ + for (x=0;x<3;x++) + if (!(freq % 5)) { + freq /= 5; + samples /=5; + } + /* No more common factors. */ + return samples; +} + +/* +** 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 + +static unsigned char linear2ulaw(short 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 > 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); +} + +int main(int argc, char *argv[]) +{ + FILE *f; + int freq1, freq2; + float wlen1, wlen2; + float val; + int x, samples1, samples2, samples=0; + char fn[256]; + if (argc < 3) { + fprintf(stderr, "Usage: gensound [freq2]\n"); + exit(1); + } + freq1 = atoi(argv[2]); + if (argc > 3) + freq2 = atoi(argv[3]); + else + freq2 = 0; + wlen1 = 8000.0/(float)freq1; + samples1 = calc_samples(freq1); + printf("Wavelength 1 (in samples): %10.5f\n", wlen1); + printf("Minimum samples (1): %d (%f.3 wavelengths)\n", samples1, samples1 / wlen1); + if (freq2) { + wlen2 = 8000.0/(float)freq2; + samples2 = calc_samples(freq2); + printf("Wavelength 1 (in samples): %10.5f\n", wlen2); + printf("Minimum samples (1): %d (%f.3 wavelengths)\n", samples2, samples2 / wlen2); + } + samples = samples1; + if (freq2) { + while(samples % samples2) + samples += samples1; + } + printf("Need %d samples\n", samples); + snprintf(fn, sizeof(fn), "%s.h", argv[1]); + if ((f = fopen(fn, "w"))) { + if (freq2) + fprintf(f, "/* %s: Generated from frequencies %d and %d \n" + " by gentone. %d samples */\n", fn, freq1, freq2, samples); + else + fprintf(f, "/* %s: Generated from frequency %d\n" + " by gentone. %d samples */\n", fn, freq1, samples); + fprintf(f, "static unsigned char %s[%d] = {\n\t", argv[1], samples); + for (x=0;x