Technical Reference:State Definition - Revision history

Mellinger: /* States */

2026-05-11T12:46:55Z

States

← Older revision		Revision as of 12:46, 11 May 2026
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	===States===		===States===
	The third kind of states is called ''Plain State'', or just ''State'', and behaves specially in that setting a state at a particular sample position in the current data block will set it to that value for all future time points. To ensure proper behavior of states at block boundaries,		The third kind of states is called ''Plain State'', or just ''State''.
	~~a special carryover value exists at the end of the state vector that does not correspond to any sample position but is used to initialize a state's values when a new block of brain signal data arrives~~.

	~~Also, with~~ regard to brain data, plain states are delayed by one block. The original BCI2000 standard required that the plain states saved with a data block are the ~~one~~ that existed when the data left the ADC, i.e. the previous state data but with the current timestamp. Thus, for backward compatibility, plain states are delayed by one block.		With regard to brain data, plain states are delayed by one block. The original BCI2000 standard required that the plain states saved with a data block are the ones that existed when the data left the ADC, i.e. the previous state data but with the current timestamp. Thus, for backward compatibility, plain states are delayed by one block.

	'''Use plain states''' to ''control the state of processing and/or application.''		'''Use plain states''' to ''control the state of processing and/or application.''

Mellinger: /* State Concept */

2026-05-11T12:45:41Z

State Concept

← Older revision		Revision as of 12:45, 11 May 2026
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	Typically, state values change once per block of data, or once per trial, but are recorded per-sample in case better resolution is required.		Typically, state values change once per block of data, or once per trial, but are recorded per-sample in case better resolution is required.
	In a [[Technical Reference:BCI2000 File Format\|BCI2000 data file]], the full set of states is stored along with the data, allowing for reconstruction of on-line system state off-line.		In a [[Technical Reference:BCI2000 File Format\|BCI2000 data file]], the full set of states is stored along with the data, allowing for reconstruction of on-line system state off-line.

			Setting a state at a particular sample position in the current data block will set it to that value for all future time points. To ensure proper behavior of states at block boundaries,
			a special carryover value exists at the end of the state vector that does not correspond to any sample position but is used to initialize a state's values when a new block of brain signal data arrives.

	==Kinds of States==		==Kinds of States==

Mellinger: /* Streams */

2026-05-11T12:43:51Z

Streams

← Older revision		Revision as of 12:43, 11 May 2026
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	This cannot be done with plain states because they are delayed by a block (see below).		This cannot be done with plain states because they are delayed by a block (see below).

	~~When the value of a stream is set for a particular sample position in the current data block, it does not affect further samples.~~		'''Use a stream state''' if you want to ''mark a certain sample or store synchronous information'' with the recorded brain signal.

	'''Use a stream state''' if you want to ''mark a certain sample or store synchronous information'' with the recorded brain signal.

	===States===		===States===

Mellinger: /* Kinds of States */

2025-07-08T10:37:20Z

Kinds of States

← Older revision		Revision as of 10:37, 8 July 2025
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	==Kinds of States==		==Kinds of States==
	Depending on subtle differences in behavior, states come in three different flavors, or kinds. All of them are recorded per-sample,		Depending on subtle differences in behavior, states come in three different flavors, or kinds. All of them are recorded per-sample (of the original brain signal data),
	and all of them are available as "States" when reading a data file.		and all of them are available as "States" when reading a data file.
	===Events===		===Events===
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	Event data are collected in a queue along with time stamps, and aligned to samples with a maximum resolution of 1ms immediately after		Event data are collected in a queue along with time stamps, and aligned to samples with a maximum resolution of 1ms immediately after
	a new block of data has been recorded.		a new block of data has been recorded.

			'''Use an event state''' if you want to record ''the time of processing or of a physical input.''

	===Streams===		===Streams===
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	When the value of a stream is set for a particular sample position in the current data block, it does not affect further samples.		When the value of a stream is set for a particular sample position in the current data block, it does not affect further samples.

			'''Use a stream state''' if you want to ''mark a certain sample or store synchronous information'' with the recorded brain signal.

	===States===		===States===
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	Also, with regard to brain data, plain states are delayed by one block. The original BCI2000 standard required that the plain states saved with a data block are the one that existed when the data left the ADC, i.e. the previous state data but with the current timestamp. Thus, for backward compatibility, plain states are delayed by one block.		Also, with regard to brain data, plain states are delayed by one block. The original BCI2000 standard required that the plain states saved with a data block are the one that existed when the data left the ADC, i.e. the previous state data but with the current timestamp. Thus, for backward compatibility, plain states are delayed by one block.

			'''Use plain states''' to ''control the state of processing and/or application.''

	==State Vector==		==State Vector==

Mellinger: /* States */

2025-07-05T10:49:46Z

States

← Older revision		Revision as of 10:49, 5 July 2025
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	a special carryover value exists at the end of the state vector that does not correspond to any sample position but is used to initialize a state's values when a new block of brain signal data arrives.		a special carryover value exists at the end of the state vector that does not correspond to any sample position but is used to initialize a state's values when a new block of brain signal data arrives.

	Also, with regard to brain data, plain states are delayed by one block. The original BCI2000 standard ~~requires~~ that the plain states saved with a data block are the one that existed when the data left the ADC, i.e. the previous state data but with the current timestamp.		Also, with regard to brain data, plain states are delayed by one block. The original BCI2000 standard required that the plain states saved with a data block are the one that existed when the data left the ADC, i.e. the previous state data but with the current timestamp. Thus, for backward compatibility, plain states are delayed by one block.

	==State Vector==		==State Vector==

Mellinger: /* States */

2025-07-05T10:48:47Z

States

← Older revision		Revision as of 10:48, 5 July 2025
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	===States===		===States===
	The third kind of states is just ~~called~~ ''State'' and behaves specially in that setting a state at a particular sample position in the current data block will set it to that value for all future time points. To ensure proper behavior of states at block boundaries,		The third kind of states is called ''Plain State'', or just ''State'', and behaves specially in that setting a state at a particular sample position in the current data block will set it to that value for all future time points. To ensure proper behavior of states at block boundaries,
	a special carryover value exists at the end of the state vector that does not correspond to any sample position but is used to initialize a state's values when a new block of brain signal data arrives.		a special carryover value exists at the end of the state vector that does not correspond to any sample position but is used to initialize a state's values when a new block of brain signal data arrives.

			Also, with regard to brain data, plain states are delayed by one block. The original BCI2000 standard requires that the plain states saved with a data block are the one that existed when the data left the ADC, i.e. the previous state data but with the current timestamp.

	==State Vector==		==State Vector==

Mellinger: /* Streams */

2025-07-05T10:45:19Z

Streams

← Older revision		Revision as of 10:45, 5 July 2025
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	===Streams===		===Streams===
	~~Similar to events, streams are only available in source modules.~~ ''Streams'' are states that are intended to be used like additional		''Streams'' are states that are intended to be used like additional
	source channels, being recorded synchronously with incoming brain signals. For an example how to use streams in conjunction with		source channels, being recorded synchronously with incoming brain signals. For an example how to use streams in conjunction with
	the <tt>BufferedADC</tt> class in a BCI2000 source module, see [[Programming_Tutorial:Implementing_a_Source_Module\|this tutorial]].		the <tt>BufferedADC</tt> class in a BCI2000 source module, see [[Programming_Tutorial:Implementing_a_Source_Module\|this tutorial]].

			Another use of streams is "annotation" of data samples during processing, e.g. with an "Artifact" marker.
			This cannot be done with plain states because they are delayed by a block (see below).

	When the value of a stream is set for a particular sample position in the current data block, it does not affect further samples.		When the value of a stream is set for a particular sample position in the current data block, it does not affect further samples.

Mellinger: /* Events */

2025-07-05T10:42:54Z

Events

← Older revision		Revision as of 10:42, 5 July 2025
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	and all of them are available as "States" when reading a data file.		and all of them are available as "States" when reading a data file.
	===Events===		===Events===
	~~These are only available in source modules.~~ ''Events'' are states that can be written to asynchronously, using the [[Programming_Reference:Events\|bcievent]] interface.		''Events'' are states that can be written to asynchronously, using the [[Programming_Reference:Events\|bcievent]] interface.
	Event data are collected in a queue along with time stamps, and aligned to samples with a maximum resolution of 1ms immediately after		Event data are collected in a queue along with time stamps, and aligned to samples with a maximum resolution of 1ms immediately after
	a new block of data has been recorded.		a new block of data has been recorded.

	===Streams===		===Streams===
	Similar to events, streams are only available in source modules. ''Streams'' are states that are intended to be used like additional		Similar to events, streams are only available in source modules. ''Streams'' are states that are intended to be used like additional

Wengelhardt at 20:19, 3 July 2025

2025-07-03T20:19:27Z

← Older revision		Revision as of 20:19, 3 July 2025
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	and all of them are available as "States" when reading a data file.		and all of them are available as "States" when reading a data file.
	===Events===		===Events===
	These are only available in source modules. ''Events'' are states that can be written to asynchronously, using the [[~~https://www.bci2000.org/mediawiki/index.php/~~Programming_Reference:Events\|bcievent]] interface.		These are only available in source modules. ''Events'' are states that can be written to asynchronously, using the [[Programming_Reference:Events\|bcievent]] interface.
	Event data are collected in a queue along with time stamps, and aligned to samples with a maximum resolution of 1ms immediately after		Event data are collected in a queue along with time stamps, and aligned to samples with a maximum resolution of 1ms immediately after
	a new block of data has been recorded.		a new block of data has been recorded.

Wengelhardt: /* Streams */

2025-06-23T16:25:19Z

Streams

← Older revision		Revision as of 16:25, 23 June 2025
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	Similar to events, streams are only available in source modules. ''Streams'' are states that are intended to be used like additional		Similar to events, streams are only available in source modules. ''Streams'' are states that are intended to be used like additional
	source channels, being recorded synchronously with incoming brain signals. For an example how to use streams in conjunction with		source channels, being recorded synchronously with incoming brain signals. For an example how to use streams in conjunction with
	the <tt>BufferedADC</tt> class in a BCI2000 source module, see [[~~https://www.bci2000.org/mediawiki/index.php/~~Programming_Tutorial:Implementing_a_Source_Module\|this tutorial]].		the <tt>BufferedADC</tt> class in a BCI2000 source module, see [[Programming_Tutorial:Implementing_a_Source_Module\|this tutorial]].

	When the value of a stream is set for a particular sample position in the current data block, it does not affect further samples.		When the value of a stream is set for a particular sample position in the current data block, it does not affect further samples.

	===States===		===States===
	The third kind of states is just called ''State'' and behaves specially in that setting a state at a particular sample position in the current data block will set it to that value for all future time points. To ensure proper behavior of states at block boundaries,		The third kind of states is just called ''State'' and behaves specially in that setting a state at a particular sample position in the current data block will set it to that value for all future time points. To ensure proper behavior of states at block boundaries,