User manual

318
Audio processing and functions
Detect Silence
• If you have zoomed in on the waveform, it may not be completely visible anymore.
In this case, the scrollbar to the left of the zoom slider allows you to scroll through
the waveform.
You can also use the mouse wheel for scrolling through the waveform.
• If the Linked option in the Detection section is deactivated, you can use the green
square at the beginning and the red square at the end of the audio file to
graphically adjust the Open and Close Threshold values (respectively). When
“Linked” is activated, you can use either square to adjust both values.
The Open and Close Threshold values in the Detection section reflect these
changes.
Making settings and processing
The lower part of the Detect Silence dialog provides settings for the detection and
processing of “silent” sections. Proceed as follows:
1. Adjust the settings in the Detection section to the left.
The settings have the following functionality:
2. Click the Compute button.
The audio event is analyzed, and the waveform display is redrawn to indicate which
sections are considered “silent” according to your settings. Above the Compute
button, the number of detected regions is displayed.
Ö If you activate the Auto checkbox next to the Compute button, the audio event is
analyzed (and the display is updated) automatically every time you change the settings
in the Detection section of the dialog. Deactivate this option when you are working
with very long files, as this process might take some time.
Setting Description
Open Threshold When the audio level exceeds this value, the function “opens”, i. e.
lets the sound pass. Audio material below the set level is detected as
“silence”. Set this value low enough to open when a sound starts, but
high enough to remove unwanted noise during “silent” sections.
Close Threshold When the audio level drops below this value, the function “closes”,
i.
e. sounds below this level are detected as “silence”. This value
cannot be higher than the Open Threshold value. Set this value high
enough to remove unwanted noise during “silent” sections.
Linked If this checkbox is activated, the Open and Close Threshold values
are always set to the same value.
Min. time open Determines the minimum time that the function will remain “open”
after the audio level has exceeded the Open Threshold value.
If the audio contains repeated short sounds, and you find that this
results in too many short “open” sections, try raising this value.
Min. time closed Determines the minimum time that the function will remain “closed”
after the audio level has dropped below the Close Threshold value.
Set this to a low value to avoid removing sounds.
Pre-roll Allows you to cause the function to “open” slightly before the audio
level exceeds the Open Threshold value. In other words, the start of
each “open” section is moved to the left according to the time you set
here.
This is useful to avoid removing the attack of sounds.
Post-roll Allows you to cause the function to “close” slightly after the audio
level drops below the Close Threshold value.
This is useful to avoid removing the natural decay of sounds.