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Sound Detection

Menu Location: Settings - Video Audio Configuration

The program can record audio from the sound card's microphone based upon sound detection. If a given percentage of the sound samples in the sound buffer are above the Sound Level then audio is recorded, otherwise not.

Therefore set the Sound Level, the Percent Above Sound Level parameters below to cause the Program to detect and record sound. Sound is only detected and recorded when both of these parameter conditions are satisfied at the same time.

Use Sound Detection

Places a check mark beside this item to enable sound detection. Also places a check mark beside Use Audio Recording.

Sound Level

Sound sample data must be greater than this value to detect sound and record. Typical value is 128.

Percent Above Sound Level

The percent of sound samples in the sound buffer which must be greater than the Sound Level to detect sound and record. Typical value is 0.01

Example: 0.01 means 0.01 of one percent. That is 110 samples in the sample buffer must be greater than the Sound Level of 128 for sound detection recording to occur. Which is Percent Above Sound Level x the Sound Buffer Sample Size = 0.01 x 11025 = 110 samples.

Sound Detection Status

Is displayed at the bottom of the Monitoring Control Window. Definitions of status is as follows:

Level = is the set Sound Level chosen above.

Above = is the set Percent Above Sound Level chosen above.

Actual = is the actual percent of sound samples above the Sound Level which is being refreshed every second when monitoring. Keep an eye on this when there is sound, and no sound, which will help you pick the value of Percent Above Sound Level to use above.

Avg = the average value of sound samples in the current sound buffer when monitoring. When there is no sound indicates what the sound level is. Good to use to help chose the value of the Sound Level you want to use.

Min = is the minimum value of sound samples in the current sound buffer when monitoring.

Max = is the maximum value of sound samples in the current sound buffer when monitoring. See its value when there is sound you want to detect. Then set the Sound Level Parameter above, to be just a bit smaller than this Max value.

Actual, Avg, Min, Max work only when you are actually monitoring, and Sound Detection is enabled.

Sound Detection Indication

You can tell when sound is detected:

1. when Saved audio status is incremented by one. The Saved status pane is displayed at the bottom of the main program window in pane number 4. It looks like Saved:x:y, where y is the number of audio buffers saved - it increments by one when sound detected.
2. whenever the value of Actual is larger than the Above value displayed in the Sound Detection status line at the bottom of the the Monitoring Control Window.

This menu item is disabled if no sound card is detected by the Program.

This menu item is also disabled if the Program cannot set the sound capture properties to 8 bits/sample, 11025 samples/second. The sound buffer size 11025 samples which contains 1 second of audio data.

Microphone input properties for your sound card is controlled by the Windows Volume Control. Double click on the yellow speaker icon on the Windows TaskBar to adjust Microphone, and Speaker Volume Control. Or click on menu item Properties to display them. One can also access the Volume Control from  Windows Control Panel, Sounds and Multimedia, under the Audio tab. Using a microphone with pre-amplifier is best.

Audio Recording