Short: Retagetable audio v4, User's Archive Type: mus/misc Author: Martin Blom Uploader: Martin Blom TITLE AHI Audio System VERSION Release 4 AUTHOR Martin Blom DESCRIPTION Retargetable Audio for AmigaOS ŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻ (When refering to this software, the correct term is 'AHI audio system' or just 'AHI', never 'Audio Hardware Interface'! 'AHI' is pronounced 'atchii', as in 'God bless!'.) Starting with version 3 of AHI, the MC68000 processor is also supported. However, many features are lacking: · 16 bit samples are converted to 8 bits before they are mixed. · No HiFi mixing routines are available. · No stereo samples · No DSP effects are available. · Less precision on some calculations · Slower As you can see, this version is very primitive. Get yourself an accelerator! I cannot guarantee that I will continue to support this processor in the future. Quick overview ŻŻŻŻŻŻŻŻŻŻŻŻŻŻ * Driver based Each supported sound card is controlled by a library-based audio driver. For a 'dumb' sound card, a new driver should be written in a few hours. For a 'smart' sound card, it is possible to utilize an on-board DSP, for example, to maximize performance and sound quality. For sound cards with own DSP but little or no memory, it is possible to use the main CPU to mix channels and do the post-processing with the DSP. Available today are drivers for · Aura (sampler only) · Delfina · DraCo Motion · Paula (8/14/14c bit) · Prelude · Toccata · Wavetools · 8SVX (mono) and AIFF/AIFC (mono & stereo) sample render * Fast, powerful mixing routines (yeah, right... haha) The device's mixing routines mix 8- or 16-bit signed samples, both mono and stereo, located in Fast-RAM and outputs 16-bit mono or stereo (with stereo panning if desired) data, using any number of channels (as long as 'any' means less than 128...). Tables can be used speed the mixing up (especially when using 8-bit samples). The samples can have any length (including odd) and can have any number of loops. * Support for non-realtime mixing By providing a timing feature, it is possible to create high- quality output even if the processing power is lacking, by saving the output to disk, for example as an IFF AIFF or 8SXV file. There are so-called HiFi mixing routines that can be used, which use linear interpolation and gives 32 bit output. * Audio database Uses ID codes, much like Screenmode IDs, to select the many parameters that can be set. The functions to access the audio database are not too different from those in 'graphics.library'. The device also features a requester to get an ID code from the user. * Both high- and low-level protocol By acting both like a device and a library, AHI gives the programmer a choice between full control and simplicity. The device API allows several programs to use the audio hardware at the same time, and the AUDIO: dos-device driver makes playing and recording sound very simple for both the programmer and user. * Future Compatible When AmigaOS gets device-independent audio worth it's name, it should not be too difficult to write a driver for AHI, allowing applications using 'ahi.device' to automatically use the new OS interface. At least I hope it wont. SPECIAL REQUIREMENTS AmigaOS release 2. MC68020 processor strongly recommended. AVAILABILITY Aminet, for example: ftp://ftp.germany.aminet.org/pub/aminet/dev/misc/ahidev.lha ftp://ftp.germany.aminet.org/pub/aminet/mus/misc/ahiusr.lha ftp://ftp.germany.aminet.org/pub/aminet/docs/misc/ahiman.lha WWW: http://www.lysator.liu.se/~lcs/ahi.html PRICE Free. But if you use it in a shareware of commercial product, I would like a registered copy for me and each of the audio driver authors (this is merely a wish, you don't have to do it if you don't think we deserve it). See the AHI User's Guide for more information. DISTRIBUTABILITY Copyright İ1994-1997 Martin Blom. Freely distributable in unmodified form. See the AHI User's Guide for more information.