Copyright (c) Hyperion Entertainment and contributors.
AHI Device
Contents
About AHI
AHI is a retargetable audio subsystem which provides standardized operating system support for wide range of audio hardware. AHI offers improved functionality not available through the AmigaOS audio device driver, such as seamless audio playback from a user selected audio device, standardized functionality for audio recording and efficient software mixing routines for combining multiple sound channels.
Definitions
Terms used in the following discussions may be unfamiliar. Some of the more important ones are defined below.
- Sample
- A sample is one binary number, representing the amplitude at a fixed point in time. A sample is often stored as an 8 bit signed integer, a 16 bit signed integer, a 32 bit floating point number etc. AHI supports only integers.
- Sample frame
- In mono environment, a sample frame is the same as a sample. In stereo environment, a sample frame is a tuple of two samples. The first member is for the left channel and the second member is for the right channel.
- Sound
Many sample frames stored in sequence as an array can be called a sound. A sound is, however, not limited to being formed by samples. It can also be parameters to an analog synth or a MIDI instrument, or be white noise. AHI supports only sounds formed by samples.
AHI Device
AHI device has two APIs: a library-like function interface for low-level access and device interface for high-level access.
