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The listener page

The listener opens your link in a browser. The page installs nothing and needs no account. It decodes the stream in the browser and renders it to the listener’s own outputs.

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Browser support

To use a multichannel interface that is not the system output, listen in Chrome or Edge. On load, Chrome and Edge ask once for microphone permission: the browser shows output names only after it is given. Nothing is recorded and the microphone closes at once. Declining is fine; the page never asks again, and outputs are then listed by number.

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Listening

The page types its header and then Press enter to listen., with the commands most listeners need underneath. Pressing Enter (or tapping the prompt on a phone) starts listening. Pressing Enter again while listening prints where things stand. The status line at the top of the page reads, for example: IAMF · 12 ch · 7.1.4 · direct · buffer 312 ms · clean That is the stream format, the number of channels rendered and the render layout, the routing, the depth of the listener’s buffer, and clean or a count of interruptions. It adds sender stopped while the sender is sending no audio, silence while the audio arriving is silent, network too slow after the listener’s network has stalled, and no audio for N s when nothing has arrived for more than 3 seconds. A stream of numbered channels shows its count and numbered (8 ch · numbered).

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Commands

Type a command at the prompt and press Enter. help lists all of them.

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Layout

layout auto (the default) plays a stream in its own layout when the output device has the outputs for it, starting on output 1: stereo on outputs 1 and 2, 5.1 on outputs 1 to 6, and so on. A stream wider than the device, or an ambisonic one, gets the richest render that fits: A numbered stream plays as sent, channel for channel, and layout leaves it as it is; route its channels with route. layout binaural renders for headphones from any stream, including ambisonics. A fixed layout (layout 7.1.4) holds whatever the device. The choice is kept in the browser for the next visit. IAMF has no four-channel render, so a quad system receives 5.1 and the page folds its six channels onto four outputs. For a 7.1 stream on four speakers, route quad maps the 7.1 channels to a quad layout directly.

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Routing to the listener’s outputs

The player is always as wide as the output device, and a routing matrix maps the stream’s channels onto the outputs. Type route to see it: each row is a channel of the stream, labelled with its speaker, and each column is an output of the interface. Clicking a cell sends that channel to that output, at once. An output fed by more than one channel is turned down to match (by the square root of the number of channels feeding it) and held under full scale. The default routing is direct, or a fold when the stream has more channels than the device has outputs. The page remembers the routing for each output device and stream width.

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Finding the speakers

test plays a soft pink noise burst on each physical output in turn, ignoring the routing, so the listener can check which speaker each output number drives before routing the stream. test 3 plays output 3 only. The test outputs button in the routing card does the same for every output.

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Messages

Of these, only a stalled network counts as a dropout, on the page and in the sender’s LISTENER DROPOUTS; a sender that stops, pauses or plays silence adds none.