Can you create a navigation system in the trimmer that mimics the AviDemux application?
They use the arrow keys for movement along the timeline with Up/Down for keyframes and Left/Right for single frames. Then Ctrl+PageUp to set a start marker and Ctrl+PageDown to set the end marker. Also allow it to scan through the video at a faster rate when using keyframes by holding down the up or down key.
Having those would make scanning through video and trimming out parts quicker.