Channel Class

From TouchDesigner 099 Wiki

A Channel object describes a single channel from a CHOP. The CHOP Class provides many ways of accessing its individual channels.

See Working with CHOPs in Python for more examples of how to use this class.


valid (Read Only) True if the referenced chanel value currently exists, False if it has been deleted.
index (Read Only) The numeric index of the channel.
name (Read Only) The name of the channel.
owner (Read Only) The OP to which this object belongs.
exports (Read Only) The (possibly empty) list of parameters this channel currently exports to.
vals Get or set the full list of Channel values. Modifying Channel values can only be done in Python within a Script CHOP.



Evaluate the channel at the specified index sample index. If no index is given, the current index based on the current time is used.
  • index - (Optional) The sample index to evaluate at.


Evaluate the channel at the specified frame. If no frame is given, the current frame is used.
  • frame - (Optional) The frame to evaluate at.


Evaluate the channel at the specified seconds. If no time is given, the current time is used.
  • secs - (Optional) The time in seconds to evaluate at.


Destroy and remove the actual Channel this object refers to. This operation is only valid when the channel belongs to a scriptCHOP.
Note: after this call, other existing Channel objects in this CHOP may no longer be valid.


Returns the average value of all the channel samples.


Returns the maximum value of all the channel samples.


Returns the minimum value of all the channel samples.

Casting to a Value

The Channel Class implements all necessary methods to be treated as a number, which in this case evaluates its current value. Therefore, an explicit call to eval() is unnecessary when used in a parameter, or in a numeric expression.

For example, the following are equivalent in a parameter:


The following are also equivalent, because the + 1 will implicitly cast the channel to a number:

 n['chan1'].eval() + 1
 n['chan1'] + 1

Special Functions

The len, subscript and assignment operators are defined to access individual samples.


Get the sample value at the specified integer index. In the Script CHOP this can be used to set sample values also.
   op('wave1').chan('abc')[5] *= 2.5


Returns the number of samples in the channel.
   c = n['chan1']
   thelength = len(c)



Returns a dictionary with persistent data about the object suitable for pickling and deep copies.


Reads the dictionary to update persistent details about the object, suitable for unpickling and deep copies.