Render is not enforced. You could choose not to use any render, and write the encoded stream into the file by yourself. You can also use a FileWriter render in the UMC sample.
I need to get raw image data only and thus I suggested that render is not needed.
However it is not possible to avoid it. Null renderer is needed in any case. Otherwise lock input data will stop responding after 6 frames are captured as you've seen from my previous questions