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"Remove Silence" Tool (Automatically)

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  • "Remove Silence" Tool (Automatically)

    DCForensics10.5 and higher includes a Remove Silence function. This is accomplished automatically after a few parameters are set by the user. This function is very useful when confronted with a very long surveillance recording in which most of the file has no talkers. The function is found under the Forensics Menu (Forensics/Remove Silence). Here is a description of the feature as found in the product documentation:

    Remove Silence Tool (Automatically)

    (Forensics Version Only)

    The Remove Silence Tool Dialog Box

    Audio surveillance recordings often include periods of silence. Often, these “dead spots” can last for long time periods. The process of manually marking and/or removing the silent sectors can be quite laborious. The Diamond Cut silence remover automatically deals with this issue. It can automatically mark the silent passages and, if desired, can then remove those “dead spots” from the recording. The system includes pre and post triggering buffers. Thus, leading and trailing edge sounds are preserved to some degree. The removal process is performed in two steps; the first step involves marking the silent sectors and the second step can be used to remove those silent sectors from an audio file. A marker will be placed at the beginning and at the end of each silent sector in the file (2 markers are used per silent sector). Here are the controls that you will need to adjust to use the Diamond Cut Forensics Remove Silence tool:

    Threshold: Sets the volume level (in dB) below which the system identifies “silence”.

    Range: 0 dB to – 100 dB (lower settings increase the systems sensitivity to “silent” passages.) If this is adjusted too low, it will trigger on background room noise; it this is adjusted too high, it will not find the silent passages. An initial setting of around -30 dB is a good place to start, but experimentation may be required on a file by file basis.

    Minimum Interval (Time): This control sets the minimum time interval that will be defined as “silence” by the systems detector. Time intervals less than this setting will not produce marked sectors of the file. This setting will vary based on the nature of the conversation on the surveillance recording. Again, experimentation is required to find the proper setting.

    Range: 1 Second to 30 Seconds

    Add Silence Between segments (Time): This allows you to insert “dead silence” in between audio segments for easier identification of the location of the breaks in conversation.

    Detect Silence (button): Clicking on this button activates the Remove Silence tool to search out silent sectors in the file. It will drop a marker at the beginning and ending of each silent sector.

    Remove Silence (button): After the silent sectors have been identified and marked by the detector portion of the algorithm, this button can be used to remove those silent sectors, if desired.

    Clear All Markers (under the Marker Menu): If you are not satisfied with the placement of the markers, you can re-adjust the “Threshold” and/or the “Minimum Interval” parameters after “Clearing All Markers” produced by an earlier attempt. Clear All Markers is not found within the Remove Silence tool dialog box; it is only found under the Marker Menu.
    Export: Allows you to export the time data via CSV formatting for use in other programs (like spreadsheets).

    Presets: A number of presets (19) are provided for use as starting points. They are expressed in the following form:

    Type XX-YY-ZZ

    Wherein -

    XX is the negative threshold in dB, YY is the Minimum Time interval in Seconds and ZZ is the Silence Added between segments.

    Note: Up to 100 markers will be shown on the time domain graph; silent sectors requiring more than 100 markers are logged and the silent areas in between those hidden markers will still be removed with the “Remove Silence” button. Silent sectors greater in 50 in number are still logged and their locations are kept in .csv format and the data can be exported.

    Related Topics
    The Forensics Menu
    Copyright (c) 1996-2020 Diamond Cut Productions, Inc.
    Last edited by Craig Maier; 06-17-2020, 09:52 AM.
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