CloudShark can take an existing capture file and create a new capture file session that has been filtered based on a time range or a filter expression.
After opening a capture file this capture file session can be exported by clicking the Export -> Create New Session button. The new capture file session can be filtered by either the current display filter, or the time range selected by the time graph sliders when a capture is opened. Annotations can also be saved in the new capture session if their packets are included by the time slider and filter expression. Once the new capture is created the resulting capture session will be opened.
The new capture fill will also have Comments that indicate which original capture file it was created from and any filters that were applied during the export.
The capture file can also be downloaded as either the original file that was uploaded or a new pcapng file including any annotations or comments that have been made with CloudShark.