Amiga Plus 1995 #2

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Archive-name: sgi/faq/audio Last-modified: Wed Dec 21 9:53:08 CST 1994 SGI audio Frequently Asked Questions (FAQ) This is one of the Silicon Graphics FAQ series, which consists of: SGI admin FAQ - IRIX system administration SGI apps FAQ - Applications and miscellaneous programming SGI audio FAQ - Audio applications and programming SGI graphics FAQ - Graphics and user environment customization SGI hardware FAQ - Hardware SGI impressario FAQ - IRIS Impressario SGI inventor FAQ - IRIS Inventor SGI misc FAQ - Introduction & miscellaneous information SGI movie FAQ - Movies SGI performer FAQ - IRIS Performer SGI pointer FAQ - Pointer to the other FAQs Read the misc FAQ for information about the FAQs themselves. Each FAQ is posted to comp.sys.sgi.misc and to the news.answers and comp.answers newsgroups (whose purpose is to store FAQs) twice per month. If you can't find one of the FAQs with your news program, you can get it by anonymous FTP from one of these sites: viz.tamu.edu:/pub/sgi/faq/ rtfm.mit.edu:/pub/usenet/news.answers/sgi/faq/ ftp.uu.net:/usenet/news.answers/sgi/faq/ Note that rtfm.mit.edu is home to many other FAQs and informational documents, and is a good place to look if you can't find an answer here. If you can't use FTP, send mail to mail-server@rtfm.mit.edu with the word 'help' on a line by itself in the text, and it will send you a document describing how to get files from rtfm.mit.edu by mail. Send the command 'send usenet/news.answers/sgi/faq/misc' to get the SGI misc FAQ, and similarly for the other FAQs. Finally, the FAQs are on the World Wide Web at http://www.cis.ohio-state.edu/hypertext/faq/usenet/sgi/top.html The SGI FAQs are freely distributable and we encourage wide circulation. You MUST keep the FAQs intact, including headers and this notice. The contents are accurate as far as we know, but the usual disclaimers apply. (In particular, copies of the SGI FAQs published on paper or CD-ROM are certain to be out of date!) Please send additions and changes to sgi-faq@viz.tamu.edu. Topics covered in this FAQ: --------------------------- -1- How do I program the Motorola 56000 DSP on the Indigo (R3K and R4K)? -2- How do I connect my stereo to my Ind{igo,igo2,y}? -3- How do I change the volume of the audio out the back of my machine? -4- Indigo2 speaker seems quieter than my Indigo. Am I imagining things? -5- I need to crank up the input gain on Indigo2 to use the microphone successfully. What's the scoop? -6- The glossy paper says that Indigo2 and Indy have 4-channel input and output. That sounds really cool. How do I use it? -7- Okay, so 4-channels of input and output is great, but I need more. Can I get more channels of audio for my machine? -8- Now that I have IRIX 5.X, I can't seem to find audio.h and libaudio.a in order to compile my audio code. What gives? -9- I like the boot tune, but it's just a bit too loud. How do I tone it down a bit? -10- How can I change the output speaker/headphone volume from a shell script? -11- What 3rd party audio solutions exist for Silicon Graphics machines? -12- I'd like to write my own audio programs. How do I get started? -13- How can I get the keyboard beep out line out/digital out on Indigo2? -14- How do I suppress the keyboard bell (which *does* come out the line out and digital output) on an Indy? -15- Why does /dev/audio not work on my Ind{y,igo2,igo}? -16- Where can I get a MOD player for SGI? -17- I need audio for my Onyx. I've heard of VigraSound. What are the details? ---------------------------------------------------------------------- Subject: -1- How do I program the Motorola 56000 DSP on the Indigo (R3K and R4K)? Date: 20 Aug 94 00:00:01 EST Short answer: You don't. Long answer: The DSP on the Indigo is used exclusively by the audio system: whenever you are using the audio, you are using the DSP. In order to insure that audio processes are serviced, access to the DSP is limited to the audio device driver which performs all functions on behalf of application programs. Moreover, any code developed for the DSP on the Indigo may not work on other systems since the DSP is not guaranteed to be present. For instance, Indigo2 and Indy do not have a DSP. Audio is supported by a combination of code running on the CPU and a audio ASIC chip. SGI supports the Audio Library software inter- face as opposed to any particular hardware implementation of the audio system. Lastly, any signal processing code developed on the host CPU benefits from speed increases of the CPU (and this code is easier to write as well). ------------------------------ Subject: -2- How do I connect my stereo to my Ind{igo,igo2,y}? Date: 20 Aug 94 00:00:01 EST The Line in and Line out levels have been designed to be directly connected to conventional stereo systems. One way to do it is to connect it up as if the computer was a tape recorder. Line out on the computer connects to Rec in on the stereo and Line in connects to Rec out. ------------------------------ Subject: -3- How do I change the volume of the audio out the back of my machine? Date: 20 Aug 94 00:00:01 EST The headphone and speaker volume is adjusted using apanel(1). The sliders under the 'Speaker' label control the output volume of the speaker and headphone. The line-level output voltage is not affected. ------------------------------ Subject: -4- Indigo2 speaker seems quieter than my Indigo. Am I imagining things? Date: 20 Aug 94 00:00:01 EST No, this is not a figment of the imagination. There are two factors at work that make the Indigo2 quieter than Indigo: 1) the speaker amp is less powerful on Indigo2; 2) the system fan on Indigo2 is louder than the Indigo fan. These two things lead to a quiet speaker that seems even quieter. See the release notes for more information. ------------------------------ Subject: -5- I need to crank up the input gain on Indigo2 to use the microphone successfully. What's the scoop? Date: 20 Aug 94 00:00:01 EST The Indigo2 and Indy both have less input gain than the Indigo and 4D/35. However, all have plenty of gain to operate the microphone. On the Indigo2 and Indy, you have to set the input gain to a larger nominal level. ------------------------------ Subject: -6- The glossy paper says that Indigo2 and Indy have 4- channel input and output. That sounds really cool. How do I use it? Date: 20 Aug 94 00:00:01 EST In order to enable 4-channel audio, you must choose "4-channel mode" from the 'Options' menu of apanel or make a call in your program to ALsetparams(3A). See the man page for ALsetparams(3A) for more infor- mation. Enabling the 4-channel mode will cause the electrical char- acteristics of your audio connections to change: the headphone jack will become a second line-level output (like the normal line-level output). The mic input will become a second line-level input *if* you have 'line' selected as your input source. If you have the input source set to 'mic', then the mic input will continue to behave as a microphone input. Lastly, when your machine is in 4-channel mode, the input and output sample rates will be locked together. Thus, changing the input or output rate in this mode will affect the output or input rate, respectively. You may also run 4-channel applications when the audio system in in 2-channel mode, and vice versa (2-channel applications work when the system is in 4-channel mode). ------------------------------ Subject: -7- Okay, so 4-channels of input and output is great, but I need more. Can I get more channels of audio for my machine? Date: 20 Aug 94 00:00:01 EST Sonic Solutions (San Raphael, CA) has announced that it is porting Sonic System to SGI platforms. See below. ------------------------------ Subject: -8- Now that I have IRIX 5.X, I can't seem to find audio.h and libaudio.a in order to compile my audio code. What gives? Date: 20 Aug 94 00:00:01 EST The #include file audio.h and the library libaudio.a became a part of the "Digital Media Developement Option" (dmdev) in IRIX 5.X. Dmdev contains more than just the audio development libraries, and it is available for an extra fee. If you are like many people and think this is a bogus situation, tell your salesperson. ------------------------------ Subject: -9- I like the boot tune, but it's just a bit too loud. How do I tone it down a bit? Date: 20 Aug 94 00:00:01 EST The boot tune volume is controlled by the 'volume' variable used by the system PROM. The value for 'volume' can be set in the range [0-255], where lower numbers represent a lower boot tune volume. A 'volume' value of 0 disables the boot tune, viz. the tune is not played at all. The value of 'volume' can be set in the PROM monitor or using the nvram(1M) command. ------------------------------ Subject: -10- How can I change the output speaker/headphone volume from a shell script? Date: 20 Aug 94 00:00:01 EST You can use two methods to do this: 1) apanel -nodisplay or volume.c program (this program can be found in ~4Dgifts/examples/ libaudio directory). ------------------------------ Subject: -11- What 3rd party audio solutions exist for Silicon Graphics machines? Date: 20 Aug 94 00:00:01 EST Doug Cook <cook@sgi.com> maintains a list of "Audio Applications for Silicon Graphics Systems" which he posts to comp.sys.sgi.audio. A copy is at viz.tamu.edu:/pub/sgi/lists/audio-apps. ------------------------------ Subject: -12- I'd like to write my own audio programs. How do I get started? Date: 20 Aug 94 00:00:01 EST First, for 5.2 systems you need the Digital Media Development Option. From Michael Portuesi (portuesi@sgi.com): The Digital Media Development Option contains the Video, Audio, Audio File, MIDI, CD, DAT, Movie, and Compression Libraries for your digital media programming enjoyment. The part number for the Digital Media Development Option is SC4-DMDEV-2.0. If you would like to develop applications which manipulate QuickTime files, you must also order the companion product, QuickTime 1.0 Compressor Library, part number SC4-QTCL-1.0. In the United States, you can order these products by calling Silicon Graphics toll-free at 1-800-800-SGI1 (1-800-800-7441). If you live in a country other than the United States, contact your nearest Silicon Graphics office, or call one of these regional telephone numbers: Europe (41) 22-798.75.25 (Geneva, CH) North Pacific (81) 3-5420.71.10 South Pacific (61) 2-879.95.00 Latin America 1(415) 390.46.37 Canada 1(416) 625-4747 For audio, example code is contained in ~4Dgifts/examples/libaudio. This example code comes with the DMDEV option. Other code demonstrating the use of the CD and DAT audio libraries can be found in a 'tar' file at ftp.sgi.com:~ftp/sgi/dat. ------------------------------ Subject: -13- How can I get the keyboard beep out line out/digital out on Indigo2? Date: 10 Dec 94 00:00:01 EST You can't. The keyboard beep is created by a chip on the Indigo2 motherboard and the signal is mixed into the analog audio signal before going to the speaker (but after then D/A converter). ------------------------------ Subject: -14- How do I suppress the keyboard bell (which *does* come out the line out and digital output) on an Indy? Date: 10 Dec 94 00:00:01 EST Turning the bell off: xset -b OR xset b off See the xset(1) man page for more details. ------------------------------ Subject: -15- Why does /dev/audio not work on my Ind{y,igo2,igo}? Date: 10 Dec 94 00:00:01 EST The /dev/audio interface was created for the older 4D/20 platform with 8-bit audio. The actual file /dev/audio remains on Ind{y,igo2,igo}. The sole interface to audio on recent SGI machines is the Audio Library and the underlying driver(s). The program 'playulaw' in the 'radio' package (ftp.cwi.nl) will play u-law data piped from standard input. (Thanks to Walter Roberson <roberson@ibd.nrc.ca>.) ------------------------------ Subject: -16- Where can I get a MOD player for SGI? Date: 10 Dec 94 00:00:01 EST There is an older version of 'tracker' by Marc Espie that runs on SGI machines. It's called tracker-al and can be found at: ftp://viz.tamu.edu/pub/sgi/software/tracker ------------------------------ Subject: -17- I need audio for my Onyx. I've heard of VigraSound. What are the details? Date: 10 Dec 94 00:00:01 EST From Scott Porter (sporter@sgi.com): VigraSound version 1.0 now available from Vigra. IRIS Audio Library software now runs on Onyx/Challenge with VigraSound VME audio board. Supported platforms: ------------------- o IP19 Onyx and Challenge systems o must be running IRIX 5.2 o current Audio Library software supports one VigraSound board per host Software: -------- o SGI and Vigra have developed an IRIS Audio Library driver module and microcode for Vigra's VigraSound (formerly "MMI-110") audio board. o The VigraSound software is binary compatible with Indigo2, Indy, Indigo, 4D/35 audio. Any SGI or 3rd party application which is linked with the IRIS Audio Library will be able to run on an IP19 system after the VigraSound board and vigrasound software module are installed. o Collaborative applications like InPerson, MediaMail, and the bundled IRIS media tools will now run with audio on an Onyx (no need to recompile or relink). o Onyx/Challenge customers may install the standard IRIS sound and movie tools (e.g. Audio Control Panel, Soundeditor, Movieplayer) from the dmedia_eoe and dmedia_tools images which are bundled with IRIX 5.2. o IP19 Onyx/Challenge developers may install the IRIS Audio Library from the dmedia_dev image which is included in the IRIS Media Libraries 2.0 software option product, along with the IRIS Media Libraries Programming Guide. Hardware: -------- o 6U VME VigraSound audio board developed by Vigra (a division of VisiCom Laboratories, Inc.) o same feature set as the Indigo/4D35 stereo audio subsystem o inputs: stereo line-level, mono microphone (input level controlled through s/w), stereo AES/EBU digital port o outputs: stereo line-level, stereo headphone (output level controlled through s/w), stereo AES/EBU digital port o independent input and output sample rates o input sample rates: 8, 11.025, 16, 22.05, 32, 44.1, 48 kHz (rate may also be slaved to AES digital input rate) o output sample rates: 8, 11.025, 16, 22.05, 32, 44.1, 48 kHz (rate may also be slaved to AES digital input rate) Sales and support: ----------------- o SGI customers purchase the VigraSound hardware/software package (including a CD which contains the vigrasound eoe s/w module) directly from Vigra, Inc. o List price for the VigraSound 1.0 hardware/software package: $3995 o Vigra contacts for the VigraSound audio product: Julie Wix Product Manager (sales contact) Rusty Wise VP, Sales and Marketing Tim Elsmore Technical Director Vigra phone (619) 597-7080 Vigra fax (619) 597-7094 Vigra is a division of VisiCom Laboratories, Inc o Customers obtain all other software (IRIX 5.2, IDO 5.2, IRIS Media Libraries 2.0, etc) from SGI. o Vigra provides front-line support for customer issues related to the VigraSound audio product (hardware and software) on IP19 Onyx/Challenge: Vigra Customer Support Group 6044A Cornerstone Court San Diego, CA 92121-4703 email: techsup@vigra.com ------------------------------ End of sgi/faq/audio Digest ****************************** -- The SGI FAQ group sgi-faq@viz.tamu.edu Finger us for info on the SGI FAQs, or look in viz.tamu.edu:/pub/sgi.