What does HRESULT 0xC00D1B66 (NS_E_INVALIDCALL_WHILE_ENCODER_RUNNING) mean?

NS_E_INVALIDCALL_WHILE_ENCODER_RUNNING

The call is valid only outside the running state

NS_E_INVALIDCALL_WHILE_ENCODER_RUNNING (0xC00D1B66) means the caller attempted to change a property or object that affects encoder topology after WMEncoder.Start. The method itself may be valid during configuration but is not valid while the graph is running.

Find the late mutation

Log encoder state and the first property/method call that returns this HRESULT. Typical suspects are source, profile, output, or preprocessing changes performed by code that assumes they remain mutable after start.

Retest

Move the change into the configuration phase before preparation/start, or stop the session before applying it. If the same call fails while stopped, diagnose that new result separately.

Technical references

• WMEncoder.Start.
• Preparing a source group for encoding.
• WMEncoder.Flush.
• Saving a Windows Media Encoder configuration.