Cannot parse rosbag in MATLab?

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I just cannot parse this bag file. So far the matlab code just looks like

filepath =fullfile(~/xxx.bag)

bagselect =rosbag(filepath)

the error on the second line is: "Expected a connection record header, but instead found Chunk. Cannot parse the file."

I know the file isn't corrupted, I can read the point values in terminal.

It's just LiDAR data off of a velodyne puck. it's not compressed, is 4GB just too big for it to read? There doesn't exist any documentation for errors this early on in the process, so I'm pretty much in the dark, any help would be appreciated. Thanks.