ALSA

Introduction

ALSA or Advanced Linux Sound Architecture is a project, which seeks to provide MIDI functionality to the Linux operating system. ALSA has the following significant features.

Features

• Effcient support for all soundcards from consumer to professional multichannel audio devices
• Fully modularized sound drivers
• SMP and thread-safe design
• alsa-lib in order to simplify the high level API
• Support for the older OSS API.

ALSA over OSS

There are many advantages ALSA has over the older OSS API:

• kernel-space supports only hardware-level capabilities
• multi-thread safe design
• transparent use of plugin architecture to handle format,rate,channel cnt and many other conversions
• support for non-interleaved interfaces
• user-space software mixing (dmix)
• user-space "loopback/snoop" capabilities
• merging multiple cards into a single virtual device
• hiding non-ALSA-drivers behind a consistent user-space API (e.g. IEEE1394 drivers, or JACK)
• consistent and generic control API for managing hardware controls
• Flexible mixer architecture to handle modern audio interfaces fully (rather than reducing them to a simplistic device)
• consistent support for multiple instances of the same card
• linked operations of multiple cards
• and more...