API Notes: MediaToolbox framework

The full API is described in Apple’s documentation, both the C and Objective-C APIs are available (but see the API Notes below).

These bindings are accessed through the MediaToolbox package (that is, import MediaToolbox).

API Notes

The full framework is available from Python. This framework was introduced in macOS 10.7.

  • MTAudioProcessingTapCreate

    The “callbacks” argument must be a tuple of 7 items, corresponding to the fields in the C structure. The second item (“clientInfo”) can be an arbitrary python object.

    The third and later elements must be None or a Python callable.


    The callbacks should not fail, if calling one of the callbacks results in an exception that exception is ignored and a warning is printed to the “stderr” stream. The exception will not be converted to an Objective-C exception.


    The process will crash if the process callback is too slow, there’s nothing PyObjC can do to prevent this.