VDMX5 Audio Analysis
From VidvoxWiki
The audio analysis plugin in takes an incoming audio signal and converts it to control data that can be used within VDMX5.
Each instance (window) of the audio analysis plugin can have any number of filters and you can have any number of audio analysis plugins running simultaneously either on the same or different input devices.
Contents |
General setup
Turning the analysis on/off
To turn the audio analysis on or off, use the Analysis on/off button in the main window of the audio analysis. When set to the off position, all processing for the plugin is disabled including the wave preview and audio pass-thru.
Adjusting the signal gain
To the left of the waveform preview is a vertical slider for adjusting the level of the input signal.
This will affect the amplitude of the wave in the preview and the actual control data produced, but will not change any audio being passed through to an output device.
Changing the source (input) device
By default the audio analysis will use whatever input device is set in the System Preferences / Sound panel. This can be overridden by opening the options panel for the audio analysis and selecting the desired device from the menu below the text 'Input Device:". This setting will be remembered with presets.
If you have multiple audio analysis plugins running at once, each can use a different input device. For example, one instance could use the built-in microphone and another could use the line input at the same time.
Audio play-thru and setting the output destination
The audio from an input device can be played through to an audio output device connected to your computer. To turn this feature on, use the audio play-thru toggle button in the options panel. When this toggle is set to on, sound will automatically be passed on to the output destination selected in the menu below the button.
When passing through, only the channels that are being listened to will be passed through. If the number of input channels is greater than the number of available channels for the selected output device, the audio analysis will automatically create a working down-mix.
Please note that if you are using the built-in microphone on a laptop and you try to pass-thru the audio to the built-in speakers, or a similar situation, this may cause an audio feedback loop which may produce an undesirable high pitched squeal. Sorry that's just how sound works.
Channel selection
In addition to being able to set an input device, each audio analysis plugin can set which input channels it should listen to. This makes it possible to perform analysis on each channel separately.
The channel selection table contains a row for each available channel for the current input device. For example, if you are using the built-in audio, there will be two rows, one for left (1) and one for right (1). When using a device that has 8 input channels, there will be 8 rows in the table and a toggle box for turning each channel on or off.
Filter Controls
Adjusting the frequency and width of a filter
Each analysis filter can be positioned either in the main displays waveform preview area, or in the options panel in the filter setup table.
With the filter setup table, the frequency and width for each filter can be set precisely by clicking on the appropriate cell in the table and typing in the value you wish to set for the frequency or width of the filter.
In the wave display, the level display for each filter also doubles as a handle which can be used to adjust the center frequency (drag left/right to the new center point) or the width of the filter (drag up to make the filter wider, drag down to make the filter narrower).
Changing the name of a filter
The name of any filter can be changed using the filter setup table in the options panel. Simply click on the row of the filter whose name you want to change in the Name column, and type in the new name. This will change the name of the filter both in the wave preview display and in the slider/button inspector's list of data sources.
Adding / removing filters
New filters can be created by clicking the 'New Analysis Band' button in the options panel. Once created, you can change the name, frequency, and width of the filter as described above.
Filters that are no longer needed can be removed by selecting them in the filter setup table and clicking the 'Delete Selected Band' button.
Setting the smoothing level for a filter
Because an audio input can sometimes be somewhat erratic, the audio analysis can apply a basic smoothing algorithm to each of it's filters. This can sometimes produce better analysis data, but if the smoothing level is set too high, the filter may appear to have a lot of latency or unresponsive. The smoothing level for each filter can be set between 0 (no smoothing) and 1 (maximum smoothing) in the filter setup table in the options panel.
Display Settings
Preparing the waveform preview for the audio analysis can be as processor intensive (if not moreso) than the creating the control data. For this reason, there are several options for throttling and disabling the waveform preview to improve overall performance.
Turning the waveform preview on/off
To save processor power, the waveform preview in the audio analysis can be disabled when it is not needed. The display can be turned on or off using the 'disable waveform' button in the main analysis interface. The same effect can also be achieved by collapsing the analysis plugin window.
Setting the waveform preview quality and speed
The audio analysis options panel contains two sliders for adjusting the overall appearance of the waveform preview. The quality slider sets the number of data points used to create the wave. A higher quality setting will give you a more detailed view of the wave which may make it easier to pinpoint where you want to position your filters, but it is more processor intensive to prepare.
Additionally, the rate at which the waveform preview updates can also be adjusted. Like with the quality slider, setting the display to update faster will give you a clearer picture of the wave, but at the cost of processor time.