BrainBay - User Manual

5.3.11 Sound Player

The Sound-Player element can be used for triggered playback of a short audio-file.

Supported file formats include wav, mp3, voc and aiff. The file could contain sound effects or reward tones of about 1 to 20 seconds length. The element is not suited for longer music files because of long loading / conversion times (use the Media Player element for longer files). The input-ports control starting of the sound (on), the current volume (vol) and the playback speed / toneheight (speed). The sound will be played when the on input is different from INVALID_VALUE.

If the option play only changes is selected, the sound will be played only once if the value of the on input-port does not change. The Repeat Interval can be used to select a minimum duration until the sound is triggered next time, thus a pause can be introduced.

The Sample Buffer Size sets the size for the internal playback buffer, this value affects the audio latency / system performance. Using values < 4096 is recommended for accurate playback.

The ranges for volume (Input-Range) and speed (Center and Factor) are obtained from the connected input signals and can be set manually by changing the values in the user dialog. The reverse option changes speedup or slowdown of the sound when the speed input values rise. The Center - value sets the value for playback at original speed and the Factor - value sets the gain for speed-changes.

5.3.12 TCP – Sender

The TCP-Sender element can be used to transfer signal channels via network, using the neuroserver software by Rudi Cilibrasi. To establish connection, a neuroserver has to be running on a known host computer in the network or on the local host. (see http://openeeg.sourceforge.net/doc/sw/NeuroServer ).

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The above picture shows a running neuroserver on the local host. The TCP-Sender element connects to this service as a client which sends biosignal data in EDFformat.

Connecting the TCP-Sender element to the neuroserver service

As in the EDF-Writer element, the first thing to do is to fill out the descriptions for the

EDF data header and channel information (see EDF-Writer element). The signal range for a specific channel is obtained from the connected input signal, it can be modified by right-clicking the input port. To connect to the neuoserver, enter the IPadress of the host computer where the service is running into the field Neuroserver of the element's user dialog. (when running a local service type 'localhost'). Press the

Connect - button. In case of a successful connection, the Status-listbox will show the lines 'Entering EEG mode' and 'OK'.

Start Sending and Stop are used to contol the data flow to the neuroserver. The button Send to neuroserver directly sends a neuroserver command written in the text field to a connected service. Use Close to disconnect from the service.

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