Audio Device Out CHOP

From TouchDesigner 099 Wiki

Summary

The Audio Device Out CHOP sends audio to any of the attached audio output devices using DirectSound or ASIO. The audio channels can be routed to any speaker location. See Outputs section below.

The second input on the Audio Device Out CHOP can be used for volume control.

Tip: If you get audio popping or audio dropouts, it may be caused by your actual frame rate of your main timeline - some frames may take too long to compute/render. See Time Slicing. There are four possible remedies:

  • The global CHOP Maximum Time Slice Size may be shorter than your worst-case time steps. Its default is .2 seconds set in Edit -> Preferences -> CHOPs -> Maximum Time Slice Size). If any frame takes longer than the Maximum Time Slice Size time to draw, audio will pop.
  • Then the audio buffer size can be increased (the Buffer Length parameter defaults to .15 seconds) up to the Maximum Time Slice Size.
  • Optimize your networks so under no condition your frame time exceeds the audio buffer size or the maximum time slice size. You can monitor this precisely with the Perform CHOP.
  • Put audio in a separate TouchDesigner process.

PythonIcon.png audiodeviceoutCHOP_Class

Parameters - Audio Device Out Page

Active /active - Turns the audio output on or off.

Driver /driver - Select between DirectSound and ASIO drivers.

  • DirectSound - the default Windows audio driver (a.k.a. WDM).
  • ASIO - low-latency drivers which usually come from the hardware's manufacturer.

Device /device - A menu of available audio devices to output to. Selecting default sets the audio device to that which is selected in Windows Control Panel>Sounds and Audio Devices>Audio>Sound Playback.

Outputs /outputs - When Driver is set to ASIO, this parameter lets you pick which output channels to use.

Buffer Length /bufferlength - The length of the audio buffer in seconds. Audio output is delayed by this amount. For example, if the Buffer Length is 0.25 then the sound will occur 250ms = 0.25 seconds later than this CHOP received it (to keep the buffer full). If you hear crackling or popping in the audio output, try increasing this value.

Volume /volume - 0 = mute, 1 = full volume.

Pan /pan - 0 = left, 0.5 = centered, 1 = right.

Clamp Output /clampoutput - Clamps the output between -1 and 1 to avoid clipping and overdriving of the audio system.

Cook Every Frame /cookalways - Forces the CHOP to cook every frame. This should be checked on at all times when outputing audio. It can be turned off when the CHOP is not in use.

Parameters - Output 1 Page

Outputs - The outputs on this page and the following Output 2 page are for routing to an audio device's different speaker outputs. Not all devices will support all outputs.

When the Audio Device Out CHOP has multiple input channels, the channels are applied to the checked speaker outputs in order. The first input channel is output to the first speaker checked, the second input channel is output to the second speaker checked, and so on.

The following speaker outputs are found on this parameter page:

Front Left
Front Right
Front Center
Low Frequency
Back Left
Back Right
Front Left of Center
Front Right of Center
Back Center

Parameters - Output 2 Page

The following speaker outputs are found on this parameter page.

Side Left
Side Right
Top Center
Top Front Left
Top Front Center
Top Front Right
Top Back Left
Top Back Center
Top Back Right

Notes

Looking at dropouts and pops

Connect an Info CHOP to the Audio Device Out CHOP and to any In CHOPs that lead to it... watch the channels of the Info CHOP to help understand what's being depleted and how. When the cook time exceeds the Time Slice size (default 150 msec), the Audio Device Out CHOP depletes and cannot recover its queue size until it pops. You need to increase the Time Slice size, but that may cause long cooks, or optimize your networks so that the cook time does not exceed the Time Slice size.

To find out how long your time slices are: Perform CHOP channel timeslice_step times the frame rate.