bsl.lsl.StreamInfo¶

class bsl.lsl.StreamInfo(name, stype, n_channels, sfreq, dtype, source_id)[source]¶

Base Stream information object, storing the declaration of a stream.

A StreamInfo contains the following information:

Core information (name, number of channels, sampling frequency, channel format, …)
Optional metadata about the stream content (channel labels, measurement units, …)
Hosting information (uID, hostname, …) if bound to an StreamInlet or StreamOutlet

Parameters:

namestr: Name of the stream. This field can not be empty.
stypestr: Content type of the stream, e.g. "EEG" or "Gaze". If a stream contains mixed content, this value should be empty and the description of each channel should include its type.
n_channelsint ≥ 1: Also called channel_count, represents the number of channels per sample. This number stays constant for the lifetime of the stream.
sfreqfloat ≥ 0: Also called nominal_srate, represents the sampling rate (in Hz) as advertised by the data source. If the sampling rate is irregular (e.g. for a trigger stream), the sampling rate is set to 0.
dtypestr: Format of each channel. If your channels have different formats, consider supplying multiple streams or use the largest type that can hold them all. One of ('string', 'float32', 'float64', 'int8', 'int16', 'int32'). 'int64' is partially supported.
source_idstr: A unique identifier of the device or source of the data. If not empty, this information improves the system robustness since it allows recipients to recover from failure by finding a stream with the same source_id on the network.

Attributes

`as_xml`	Retrieve the entire stream_info in XML format.
`created_at`	Timestamp at which the stream was created.
`desc`	Extended description of the stream.
`dtype`	Channel format of a stream.
`hostname`	Hostname of the providing machine.
`n_channels`	Number of channels.
`name`	Name of the stream.
`protocol_version`	Version of the LSL protocol.
`session_id`	Session ID for the given stream.
`sfreq`	Sampling rate of the stream, according to the source (in Hz).
`source_id`	Unique identifier of the stream's source.
`stype`	Type of the stream.
`uid`	Unique ID of the `StreamOutlet` instance.

property as_xml¶

Retrieve the entire stream_info in XML format.

This yields an XML document (in string form) whose top-level element is <info>. The info element contains one element for each field of the StreamInfo class, including:

the core elements name, type (eq. stype), channel_count (eq. n_channels), nominal_srate (eq. sfreq), channel_format (eq. dtype), source_id
the misc elements version, created_at, uid, session_id, v4address, v4data_port, v4service_port, v6address, v6data_port, v6service_port
the extended description element desc with user-defined sub-elements.

property created_at¶

Timestamp at which the stream was created.

This is the time stamps at which the stream was first created, as determined by local_clock on the providing machine.

property desc¶

Extended description of the stream.

It is highly recommended that at least the channel labels are described here. See code examples on the LSL wiki. Other information, such as amplifier settings, measurement units if deviating from defaults, setup information, subject information, etc.. can be specified here, as well. Meta-data recommendations follow the XDF file format project.

Important: if you use a stream content type for which meta-data recommendations exist, please try to lay out your meta-data in agreement with these recommendations for compatibility with other applications.

property dtype¶

Channel format of a stream.

All channels in a stream have the same format.

property hostname¶: Hostname of the providing machine.

property n_channels¶

Number of channels.

A stream must have at least one channel. The number of channels remains constant for all samples.

property name¶

Name of the stream.

The name of the stream is defined by the application creating the LSL outlet. Streams with identical names can coexist, at the cost of ambiguity for the recording application and/or the experimenter.

property protocol_version¶

Version of the LSL protocol.

The major version is version // 100. The minor version is version % 100.

property session_id¶

Session ID for the given stream.

The session ID is an optional human-assigned identifier of the recording session. While it is rarely used, it can be used to prevent concurrent recording activities on the same sub-network (e.g., in multiple experiment areas) from seeing each other’s streams (can be assigned in a configuration file read by liblsl, see also Network Connectivity in the LSL wiki).

property sfreq¶

Sampling rate of the stream, according to the source (in Hz).

If a stream is irregularly sampled, the sampling rate is set to 0.

property source_id¶

Unique identifier of the stream’s source.

The unique source (or device) identifier is an optional piece of information that, if available, allows endpoints (such as the recording program) to re-acquire a stream automatically once if it came back online.

property stype¶

Type of the stream.

The content type is a short string, such as "EEG", "Gaze", … which describes the content carried by the channel. If a stream contains mixed content, this value should be an empty string and the type should be stored in the description of individual channels.

property uid¶

Unique ID of the StreamOutlet instance.

This ID is guaranteed to be different across multiple instantiations of the same StreamOutlet, e.g. after a re-start.