[FieldTrip] slow reading with ft_preprocessing of a fcdc_matbin file?

van Lier Ben ben.vanlier at bsse.ethz.ch
Thu Aug 29 13:53:26 CEST 2013

Hi all,

I have a pretty big data file of 120 channels for 20min continuous at 20khz. clearly i need to downsample. to do so, i convert the original file to fcdc_matbin, creating a 22gb bin file with all the data.

then its time for downsampling as shown on http://fieldtrip.fcdonders.nl/faq/how_can_i_preprocess_a_dataset_that_is_too_large_to_fit_into_memory

this is very slow. ft_preprocessing takes 230 seconds per channel (using 380 mb), doing nothing but just reading 1 channel. the subsequent downsampling with ft_resample to 1khz is surprisingly fast with only 4 seconds.

does that make any sense? it seems like a very long time to read in 380mb... :(


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