ahidev_4.18 4.18

Retargetable audio 4.18,Developer archive

Short:        Retargetable audio 4.18,Developer archive
Author:       Martin Blom <lcs@lysator.liu.se>
Uploader:     Christoph Fassbach <christoph fassbach gmail com>
Type:         dev/misc
Version:      4.18
Architecture: m68k-amigaos >= 2.0.4

     Re-upload of the ancient 4.18 developer archives for
     historical reference - and lovers of old machines 
     being therefore in need of AHI4.

     Documentation updated over version 4.16.

     Original ReadMe content below:
     ------------------------------

     This archive contains the developer documentation and
     example source code for AHI, both for programmer who wish
     to use AHI in their own applications and those who want
     to write hardware drivers.

     Changes since last release
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     Bug fixes in the device code.
     Updated documentation.
     New translation (hrvatski).
     Added driver for Maestro Pro to the distribution.
     Added driver for Concierto to the distribution.


TITLE

     AHI Audio system

VERSION

     Release 4

AUTHOR

     Martin Blom <lcs@lysator.liu.se>

DESCRIPTION

     Retargetable Audio for AmigaOS
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     (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:

     · Very limited volime control when using 16 bit samples
     · 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
     ¯¯¯¯¯¯¯¯¯¯¯¯¯¯

     * 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)
     · Clarity (sampler only)
     · Concierto (Picasso IV sound module)
     · Delfina DSP and Delfina Lite
     · DraCo Motion
     · Maestro Pro
     · Melody MPEG
     · 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 or better 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 ©1994-1997 Martin Blom.
     Freely distributable in unmodified form.
     See the AHI User's Guide for more information.