int sm_vmptx_destroy(tSMVMPtxId vmptx)
Destroys vmptx and invalidates the tSMVMPtxId. Normally, a VMP[tx] will only be destroyed when it is in the stopped state. If the VMP[tx] is not in the stopped state, it will be implicitly stopped. It is an error to refer to a VMP[tx] once it has been destroyed.
If a call to sm_vmptx_create() completes successfully, sm_vmptx_stop() should be used to stop to the VMP[tx] and move it into the stopped state.
0 if call completed successfully, otherwise a standard error such as:
This function is part of the Prosody RTP processing API.