Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!usc!cs.utexas.edu!uwm.edu!ux1.cso.uiuc.edu!csrd.uiuc.edu!s4.csrd.uiuc.edu!bruner From: bruner@sp15.csrd.uiuc.edu (John Bruner) Newsgroups: comp.sys.mac.programmer Subject: Re: Mac sounds to Sparc Message-ID: Date: 27 Mar 91 14:58:14 GMT References: <1991Mar27.015629.9536@oracle.com> Sender: news@csrd.uiuc.edu (news) Organization: CSRD, University of Illinois Lines: 26 In-Reply-To: dpawson@oracle.com's message of 27 Mar 91 01:56:29 GMT For some time I've been tempted to write a program to convert Mac 'snd ' resources into SPARC audio files. However, I never seem to assemble all of the necessary documentation (Mac + Sun) in one place at the same time. The Sun audio files are sampled at 8kHz and are stored in an encoded format. The Sun documentation refers to this as ISDN "mu-law" encoding, which I'm sure is a standard encoding but to which I have no reference. According to the Sun audio_ulaw2linear(3) manual page "The u-law transfer function results in a nearly linear relationship to PCM [Pulse Code Modulated] at low amplitudes and a logarithmic relationship at high amplitudes. Another wrinkle is that the audio is stored in one's complement sign-magnitude format on the Sun. Sun's documentation indicates that the format of its audio files is a subset of the format on the NeXT. I've heard that there is a program that converts Mac <-> NeXT audio formats, but I haven't tracked it down yet. If you just FTP'd the sound in binary, then the Sun "play" program probably assumed some default format for the data, most likely 8-bit mu-law encoding sampled at 8kHz. I suspect this accounts for the "vacuum cleaner" you're hearing. -- John Bruner Center for Supercomputing R&D, University of Illinois bruner@csrd.uiuc.edu (217) 244-4476