wavexlrfix.lua

-- This script creates a virtual sink to link Wave XLR source (mirophone input) to.
-- After the link is estabilished it creates Wave XLR sink (playback output).
log = Log.open_topic("s-wavexlrfix")

waveXlrSourceOm = ObjectManager {
    Interest {
        type = "node",
        Constraint { "node.name", "matches", "wavexlr-source" },
    }
}

linkOm = ObjectManager {
    Interest {
        type = "link",
    }
}

devicesOm = ObjectManager {
    Interest {
        type = "device",
    }
}

waveXlrSinkNode = nil
nullSinkForWaveXlrSource = nil
nullSinkLink = nil

function createLinkForWaveXlrSource(waveXlrSourceNode)
    local outPort = nil
    local inPort = nil

    local outInterest = Interest {
        type = "port",
        Constraint { "node.id", "equals", waveXlrSourceNode.properties["object.id"] },
        Constraint { "port.direction", "equals", "out" }
    }

    local inInterest = Interest {
        type = "port",
        Constraint { "node.id", "equals", nullSinkForWaveXlrSource.properties["object.id"] },
        Constraint { "port.direction", "equals", "in" }
    }

    local portOm = ObjectManager {
        Interest {
            type = "port",
        }
    }

    function onPortAdded()
        if not nullSinkLink then
            for port in portOm:iterate(outInterest) do
                outPort = port
            end

            for port in portOm:iterate(inInterest) do
                inPort = port
            end

            if inPort and outPort and inPort.properties["object.id"] and outPort.properties["object.id"] then
                local args = {
                    ["link.input.node"] = waveXlrSourceNode.properties["object.id"],
                    ["link.input.port"] = inPort.properties["object.id"],

                    ["link.output.node"] = nullSinkForWaveXlrSource.properties["object.id"],
                    ["link.output.port"] = outPort.properties["object.id"],
                }

                log:notice("Creating link between null sink and WaveXLR source. Ports: " ..
                    args["link.input.port"] .. " -> " .. args["link.output.port"])

                nullSinkLink = Link("link-factory", args)
                nullSinkLink:activate(Feature.Proxy.BOUND)
            end
        end
    end

    portOm:connect("object-added", onPortAdded)
    portOm:activate()
end

function onLinkCreated(_, link)
    if nullSinkLink and link.properties["object.id"] == nullSinkLink.properties["object.id"] then
        for node in waveXlrSourceOm:iterate() do
            createWaveXlrSink(node)
        end
    end
end

function createWaveXlrSink(sourceNode)
    local deviceInterest = Interest {
        type = "device",
        Constraint { "object.id", "equals", sourceNode.properties["device.id"] }
    }

    for device in devicesOm:iterate(deviceInterest) do
        local sinkNodeProperties = {
            ["device.id"] = sourceNode.properties["device.id"],
            ["factory.name"] = "api.alsa.pcm.sink",
            ["node.name"] = "wavexlr-sink",
            ["node.description"] = "WaveXLR Sink",
            ["node.nick"] = "WaveXLR Sink",
            ["media.class"] = "Audio/Sink",
            ["api.alsa.path"] = sourceNode.properties["api.alsa.path"],
            ["api.alsa.pcm.card"] = sourceNode.properties["api.alsa.pcm.card"],
            ["api.alsa.pcm.stream"] = "playback",
            ["alsa.resolution_bits"] = "24",
            ["audio.channels"] = "2",
            ["audio.position"] = "FL,FR",
            ["priority.driver"] = "1000",
            ["priority.session"] = "1000",
            ["node.pause-on-idle"] = "false",
        }

        for k, v in pairs(device.properties) do
            if k:find("^api%.alsa%.card%..*") then
                sinkNodeProperties[k] = v
            end
        end

        log:notice("Creating custom WaveXLR sink. api.alsa.path: " .. sourceNode.properties["api.alsa.path"])

        waveXlrSinkNode = Node("adapter", sinkNodeProperties)
        waveXlrSinkNode:activate(Feature.Proxy.BOUND, function(n, err)
            if err then
                log:warning("Failed to create " .. sinkNodeProperties["node.name"]
                    .. ": " .. tostring(err))
                waveXlrSinkNode = nil
            else
                log:notice("Created custom WaveXLR sink. object.id: " .. n.properties["object.id"])
            end
        end)
    end
end

function onWaveXlrSourceAdded(_, node)
    createLinkForWaveXlrSource(node)
end

function createNullSink()
    local properties = {
        ["factory.name"] = "support.null-audio-sink",
        ["node.name"] = "null-sink-for-wavexlr-source",
        ["node.description"] = "Null Sink For WaveXLR Source - do not use",
        ["node.nick"] = "Null Sink For WaveXLR Source - do not use",
        ["media.class"] = "Audio/Sink",
        ["monitor.channel-volumes"] = "true",
        ["monitor.passthrough"] = "true",
        ["audio.channels"] = "1",
        ["audio.position"] = "MONO",
        ["node.passive"] = "false"
    }

    log:notice("Creating custom null sink for WaveXLR Source")

    local node = Node("adapter", properties)

    node:activate(Feature.Proxy.BOUND, function(n, err)
        if err then
            log:warning("Failed to create " .. properties["node.name"]
                .. ": " .. tostring(err))
            node = nil
        else
            log:notice("Created null sink for WaveXLR source. object.id: " ..
                n.properties["object.id"])
        end
    end)

    return node
end

function onWaveXlrSourceRemoved()
    if waveXlrSinkNode then
        log:notice("Removing custom WaveXLR sink");
        waveXlrSinkNode:request_destroy()
        waveXlrSinkNode = nil
    end

    if nullSinkLink then
        log:notice("Removing null sink link");
        nullSinkLink:request_destroy()
        nullSinkLink = nil
    end
end

nullSinkForWaveXlrSource = createNullSink();

devicesOm:activate()
linkOm:activate()
linkOm:connect("object-added", onLinkCreated)
waveXlrSourceOm:connect("object-added", onWaveXlrSourceAdded)
waveXlrSourceOm:connect("object-removed", onWaveXlrSourceRemoved)
waveXlrSourceOm:activate()

log:notice("script initialized")