[Mne_analysis] mne_brain_vision2fiff Losing Events?

[Alexandre Gramfort]

hi Christian,

I confirm that I find 1958 events in your file with both
mne_process_raw and mne-python

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

indeed reports 1960 events although with

$mne_process_raw --raw test_raw.fif --events test-eve.fif

and loading test-eve.fif in Python I get only 1958

>>> import mne
>>> ev = mne.read_events('test_raw-eve.fif')
>>> len(ev[ev[:, 2] == 128])
1958

I therefore suspect an issue in the C code maybe while writing the
stim channel to fif.

We'll have to dig in the C code and maybe Matti can give us a hand.

Alex

On Wed, Aug 15, 2012 at 6:50 PM, Christian Brodbeck <cmb650 at nyu.edu> wrote:
> 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]
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