[Mne_analysis] mne_brain_vision2fiff Losing Events?

[Christian Brodbeck]

Hello,

When converting with mne_brain_vision2fiff, the resulting fif files seem to be missing events on occasion. My recordings should all contain 1960 events. mne_brain_vision2fiff says "nevent = 1960" (for the complete output see below), however, when opening the resulting fiff files in mne-python, up to 3 events are missing. The conversion seems to lose events consistently (i.e. when I repeat the command the same number of events get lost):

n events found by mne-python for my different subjects:
1959   R0040_eref3h_raw.fif
1958   R0458_eref3h_raw.fif
1957   R0425_eref3h_raw.fif
1957   R0355_eref3h_raw.fif
1960   R0273_eref3h_raw.fif
1960   R0541_eref3h_raw.fif

The event channel data reflects that (for a recording with 1958 events):

>>> np.unique(data)
array([   0.,  128.])
>>> np.sum(np.diff(data) > 0)
1958
>>> np.sum(np.diff(data) < 0)
1958

I also tried the nightly version of mne with the same result. In case someone can have a look, I uploaded a set of files (10 mb): https://dl.dropbox.com/u/659990/R0458%20eref3h.zip

Thanks

Christian







$ mne_brain_vision2fiff --header R0458_eref3h.vhdr --out R0458_eref3h.fif 

mne_brain_vision2fiff version 1.7 compiled at Jan  7 2011 02:26:21

header  file           : R0458_eref3h.vhdr
output file            : R0458_eref3h.fif

Read header file : R0458_eref3h.vhdr
Read header file : R0458_eref3h.vmrk

nchan           = 5
sfreq           = 500.0  Hz
raw data file   = R0458_eref3h.eeg
raw binary      = true
raw binary type = 16
raw endian      = little
raw nsamp       = -1
nevent          = 1960
eXimia          = false

Data will be split into <= 1907.3 MByte pieces

Writing header to R0458_eref3h_raw.fif ... [done]
Writing raw data to R0458_eref3h_raw.fif ... Number of samples deduced from the raw file size : 671230
[done]
Wrote 1...671230 of 671230 samples total to R0458_eref3h_raw.fif
Adding directory to R0458_eref3h_raw.fif...[done]