Crate audiostream

Audio stream pipelines and processing.

Streams are represented as sequences of buffers, each of which contains zero or more samples. Data is produced from Sources on demand and fed into a chain of zero or more Sinks until it reaches the end of the pipeline. The pipeline always operates in a "pull" mode, where Sources yield buffers only as fast as requested by a Sink.

Samples

Valid sample formats are bounded by the Sample trait. In general a sample will be a primitive numeric value, though this need not be true. Sample values must always be copyable and sendable between threads, and most non-trivial stream transformations require that a number of arithmatic operations be available.

Clipping

In all formats, the nominal range is between -1 and 1, inclusive. In integer formats, the logical interpretation is as a fixed-point value with the radix point left-aligned. For example, a i8 Sample is best considered as a number in range -128/128 through 127/128 by steps of 1/128.

A format is considered soft-clipped if it is capable of representing values outside the nominal range. Notably, this applies to floating-point formats where numbers outside the nominal range can be represented (but perhaps with some loss of precision). The converse of a hard-clipped format is soft-clipped.

Source taxonomy

From least general to most, there are three classes of sources, each of which yield different "flavors" of output. * MonoSources simply provide a stream of samples of a statically-known format. This stream is strictly linear and can only mark end-of-stream. * Source is the general static element, providing blocks of a statically-known sample format. It may pass an arbitrary number of channels at a time and specifies the stream's sample rate. * A DynamicSource has no properties known at compile-time. Sample format and rate are specified on a per-buffer basis, requiring reinterpretation of the data before use.

A less-general source can always be adapted into a more-general source. A MonoAdapter converts MonoSource to Source, and DynAdapter converts Source to DynamicSource.

Modules

ao	libao sink
synth	Signal synthesizers.
vorbis	Ogg vorbis decoder.

Structs

Amplify	Adjust the amplitude of the input stream by a constant factor.
CopyChannel	Make a copy of a specified channel.
DynAdapter	Adapts a normal Source into a DynamicSource.
DynBuffer	The result of pulling from a DynamicSource.
MonoAdapter	Generalizes a MonoSource into Source.
UninitializedSource	A source of uncontrolled samples.

Enums

SourceResult

Output from Source pull.

Traits

DynamicSource	A Source with format known only at runtime.
MonoSource	A Source that only generates one channel at an indeterminate sample rate.
Sample	Type bound for sample formats.
Sink	A thing.
Source	A source of samples with defined sample rate.