ALSA <-> Oboe I/O PCM Plugin

Description

ALSA's userspace library (alsa-lib) has a plugin system that allows for userspace software devices rather than a device backed by a kernel driver. This is already utilized for various plugins at the ALSA plugins repository, including the JACK and PulseAudio plugin which translate ALSA calls into their corresponding API, similar to what this plugin does.

This plugin allows using an unmodified version of alsa-lib to call into Oboe, a C++ library for high-performance audio on Android, allowing for any applications that use ALSA (such as Wine and SDL-based applications, which are the primary targets) to have functional audio on Android without any other changes.

Configuration (.asoundrc)

• Basic: This will only support anything directly exposed by the plugin, that being mono/stereo S16/S24_3/S32/FLOAT LE @ 8kHz-48kHz audio.

pcm.!default {
    type oboe
    hint {
        show {
            @func refer
            name defaults.namehint.basic
        }
        description "Oboe PCM"
    }
}

• Advanced: Adding plug in front of the plugin allows for any unsupported format, channel or rate to be automatically converted into a supported equivalent.

pcm.!default {
    type plug
    slave {
        pcm {
            type mmap_emul
            slave.pcm {
                type oboe
            }
        }
        format S16_LE
        rate unchanged
        channels unchanged
    }
    hint {
        show {
            @func refer
            name defaults.namehint.basic
        }
        description "Oboe PCM"
    }
}