jms@tardis.Tymnet.COM (Joe Smith) (06/02/91)
In article <20014@sdcc6.ucsd.edu> smaschue@sdcc13.ucsd.edu (sean) writes: >I am trying to write a gnu c program to convert sound files from that wacky >SPARC format to mac format. I followed the alogrithm that someone mentioned >a few days ago (just add 127) and this does not seem to work. To convert from signed 8-bit format (as used by the Amiga and Atari ST) to unsigned 8-bit format (as used on the Mac), go through the file and for every byte: a) add 128 b) subtract 128 c) XOR with 0x80 d) any one of the above. To convert from u-law format (such as used on Sun's SPARC) to Mac format, first convert from u-law to linear and then do the above conversion. The "u-law" encoding is similar to a sign-magnitude floating-point number stored in one's-complement form. This table shows what happens when the data is converted from u-law to linear, and scaled so that the results are between -127 and +127. In general, the conversion is from 8-bit u-law to 16-bit linear shifted right by 8 bits. This table uses floating-point output to demonstrate that u-law has a much finer resolution than 8-bit linear code. 00 -125.48 25 -25.98 4A -4.86 6F -0.52 94 54.48 B9 10.73 DE 1.67 01 -121.48 26 -24.98 4B -4.61 70 -0.47 95 52.48 BA 10.23 DF 1.55 02 -117.48 27 -23.98 4C -4.36 71 -0.44 96 50.48 BB 9.73 E0 1.45 03 -113.48 28 -22.98 4D -4.11 72 -0.41 97 48.48 BC 9.23 E1 1.39 04 -109.48 29 -21.98 4E -3.86 73 -0.38 98 46.48 BD 8.73 E2 1.33 05 -105.48 2A -20.98 4F -3.61 74 -0.34 99 44.48 BE 8.23 E3 1.27 06 -101.48 2B -19.98 50 -3.42 75 -0.31 9A 42.48 BF 7.73 E4 1.20 07 -97.48 2C -18.98 51 -3.30 76 -0.28 9B 40.48 C0 7.36 E5 1.14 08 -93.48 2D -17.98 52 -3.17 77 -0.25 9C 38.48 C1 7.11 E6 1.08 09 -89.48 2E -16.98 53 -3.05 78 -0.22 9D 36.48 C2 6.86 E7 1.02 0A -85.48 2F -15.98 54 -2.92 79 -0.19 9E 34.48 C3 6.61 E8 0.95 0B -81.48 30 -15.23 55 -2.80 7A -0.16 9F 32.48 C4 6.36 E9 0.89 0C -77.48 31 -14.73 56 -2.67 7B -0.12 A0 30.98 C5 6.11 EA 0.83 0D -73.48 32 -14.23 57 -2.55 7C -0.09 A1 29.98 C6 5.86 EB 0.77 0E -69.48 33 -13.73 58 -2.42 7D -0.06 A2 28.98 C7 5.61 EC 0.70 0F -65.48 34 -13.23 59 -2.30 7E -0.03 A3 27.98 C8 5.36 ED 0.64 10 -62.48 35 -12.73 5A -2.17 7F 0.00 A4 26.98 C9 5.11 EE 0.58 11 -60.48 36 -12.23 5B -2.05 80 125.48 A5 25.98 CA 4.86 EF 0.52 12 -58.48 37 -11.73 5C -1.92 81 121.48 A6 24.98 CB 4.61 F0 0.47 13 -56.48 38 -11.23 5D -1.80 82 117.48 A7 23.98 CC 4.36 F1 0.44 14 -54.48 39 -10.73 5E -1.67 83 113.48 A8 22.98 CD 4.11 F2 0.41 15 -52.48 3A -10.23 5F -1.55 84 109.48 A9 21.98 CE 3.86 F3 0.38 16 -50.48 3B -9.73 60 -1.45 85 105.48 AA 20.98 CF 3.61 F4 0.34 17 -48.48 3C -9.23 61 -1.39 86 101.48 AB 19.98 D0 3.42 F5 0.31 18 -46.48 3D -8.73 62 -1.33 87 97.48 AC 18.98 D1 3.30 F6 0.28 19 -44.48 3E -8.23 63 -1.27 88 93.48 AD 17.98 D2 3.17 F7 0.25 1A -42.48 3F -7.73 64 -1.20 89 89.48 AE 16.98 D3 3.05 F8 0.22 1B -40.48 40 -7.36 65 -1.14 8A 85.48 AF 15.98 D4 2.92 F9 0.19 1C -38.48 41 -7.11 66 -1.08 8B 81.48 B0 15.23 D5 2.80 FA 0.16 1D -36.48 42 -6.86 67 -1.02 8C 77.48 B1 14.73 D6 2.67 FB 0.12 1E -34.48 43 -6.61 68 -0.95 8D 73.48 B2 14.23 D7 2.55 FC 0.09 1F -32.48 44 -6.36 69 -0.89 8E 69.48 B3 13.73 D8 2.42 FD 0.06 20 -30.98 45 -6.11 6A -0.83 8F 65.48 B4 13.23 D9 2.30 FE 0.03 21 -29.98 46 -5.86 6B -0.77 90 62.48 B5 12.73 DA 2.17 FF 0.00 22 -28.98 47 -5.61 6C -0.70 91 60.48 B6 12.23 DB 2.05 23 -27.98 48 -5.36 6D -0.64 92 58.48 B7 11.73 DC 1.92 24 -26.98 49 -5.11 6E -0.58 93 56.48 B8 11.23 DD 1.80 Most of the following program was extracted from posting by Brian Foley. Brian Foley email: bfoley@greatlakes.Central.Sun.COM Systems Engineer snail-mail: 1000 Town Center Sun Microsystems Suite 1700 GreatLakes Region Southfield, MI 48075 (313)352-7070 #include <stdio.h> #include <math.h> /* The following main() routine is by Joe Smith <jms@tardis.tymnet.com> */ main() { int i; unsigned char data; for (i=0; i<256; i++) { /* Create a ulaw to linear table. */ data = i; /* (scaled so output is +/- 128.) */ printf("%02X %6.2f\n",i,(float)ulaw2linear(data)/256.0); } } /** ** Signal conversion routines for use with the Sun4/60 audio chip **/ /* * This routine converts from ulaw to 16 bit linear * 29 September 1989 * * Craig Reese: IDA/Supercomputing Research Center * * 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 */ int ulaw2linear(ulawbyte) unsigned char ulawbyte; { static int exp_lut[8]={0,132,396,924,1980,4092,8316,16764}; int sign, exponent, mantissa, 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); } /* * This routine converts from linear to ulaw * 29 September 1989 * * Craig Reese: IDA/Supercomputing Research Center * Joe Campbell: Department of Defense * * 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 linear2ulaw(sample) int 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 the result **/ return(ulawbyte); } -- Joe Smith (408)922-6220 | SMTP: jms@tardis.tymnet.com or jms@gemini.tymnet.com BT Tymnet Tech Services | UUCP: ...!{ames,pyramid}!oliveb!tymix!tardis!jms PO Box 49019, MS-C51 | BIX: smithjoe | CA license plate: "POPJ P," (PDP-10) San Jose, CA 95161-9019 | humorous dislaimer: "My Amiga 3000 speaks for me."
droman@amiglynx.UUCP (Dan Roman) (06/05/91)
Do you or anyone else know of a program which already exists for converting
the Sun audio files to Amiga 8SVX? I'm lazy and don't want to do it myself if
it already exists! Thanks for the info though, it will be a great start if I
get around to writing a conversion program!
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Dan Roman Internet: droman@amiglynx.nj.us A1000 --> A3000 Finally!
Where am I going? I didn't know I was going ANYWHERE!
Relax, don't worry, have a homebrew.wbrand@krishna.shearson.com (Willy Brandsdorfer) (06/06/91)
In article <droman.5052@amiglynx.UUCP> droman@amiglynx.UUCP (Dan Roman) writes: > Do you or anyone else know of a program which already exists for converting > the Sun audio files to Amiga 8SVX? I'm lazy and don't want to do it myself if > it already exists! Thanks for the info though, it will be a great start if I > get around to writing a conversion program! There are 2 programs on irisa.irisa.fr (131.254.2.3); GOODIES/Iff2uLaw.tar.Z and GOODIES/uLaw2Iff.tar.z I have used the first one and it's great. I haven't tried the second one yet, but it should work fine. ------------------------------------------------------------------------------ William Brandsdorfer | UUCP: !uunet!shearson.com!wbrand Lehman Brothers | ARPA: wbrand@shearson.com 388 Greenwich St. | Voice: (212) 464-3835 New York, N.Y. 10013 -------------------------------------------------------------------------------
droman@amiglynx.UUCP (Dan Roman) (06/10/91)
For those of us who can't get to Iff2ulaw.tar.Z etc. in irisa.irisa.fr is
there any chance we might find these programs up on GEnie for example?
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Dan Roman Internet: droman@amiglynx.nj.us GEnie: D.ROMAN1
A1000 --> 3000 FINALLY!!! Relax, don't worry, have a homebrew!lord_zar@ucrmath.ucr.edu (wayne wallace) (06/10/91)
droman@amiglynx.UUCP (Dan Roman) writes: >For those of us who can't get to Iff2ulaw.tar.Z etc. in irisa.irisa.fr is >there any chance we might find these programs up on GEnie for example? Try ftp'ing to ucsd.edu instead!!!! Both Iff2Ulaw.tar.Z and Ulaw2Iff.tar.Z are in /sparcaudio or /sounds..... >Dan Roman Internet: droman@amiglynx.nj.us GEnie: D.ROMAN1 Wayne
jms@vanth.UUCP (Jim Shaffer) (06/13/91)
In article <lord_zar.676572839@ucrmath> lord_zar@ucrmath.ucr.edu (wayne wallace) writes: >droman@amiglynx.UUCP (Dan Roman) writes: > >>For those of us who can't get to Iff2ulaw.tar.Z etc. in irisa.irisa.fr is >>there any chance we might find these programs up on GEnie for example? > >Try ftp'ing to ucsd.edu instead!!!! Both Iff2Ulaw.tar.Z and Ulaw2Iff.tar.Z >are in /sparcaudio or /sounds..... I know that the connectivity of .EDU, .COM, etc. domains is difficult to determine these days, but when a node ends in .UUCP, you can be sure it does NOT have a TCP/IP connection to the Internet. (Yes, I know about ftpmail etc., but that's not the point.) -- * From the disk of: | jms@vanth.uucp | "Let's become Jim Shaffer, Jr. | amix.commodore.com!vanth!jms | alive again." 37 Brook Street | uunet!cbmvax!amix!vanth!jms | Montgomery, PA 17752 | 72750.2335@compuserve.com | --Yes