Ok. It makes the point really clear, no data transformation related to hdf5. 
I'didn't find any information about data transformation values in the rest of 
the files, just min/max possible values and filters applied to the channels.


I will ask the manufacturer to go further in this question.


Many thanks for your answer.


Florian

________________________________
De : Hdf-forum <[email protected]> de la part de David 
<[email protected]>
Envoyé : vendredi 11 mars 2016 01:17
À : HDF Users Discussion List
Objet : Re: [Hdf-forum] H5T_IEEE_F32LE 2D array modified values

HDF5 doesn't know anything about your channels. The fact that channels are 
stored in alternating values of the dataset is only known by the application 
(and you). HDF5 does not do any transformations on the data. If it is asked to 
store a value as F32LE it just stores the value. Same with retrieval. You will 
have to find out from vendor how to convert the stored values to the units you 
are interested in. They are possibly just storing raw sensor data in volts or 
something similar. I would also poke around the rest of file and look for 
attributes they might have stored conversion factors in.

David

On Wed, Mar 9, 2016 at 1:26 PM, Florian Chmetz 
<[email protected]<mailto:[email protected]>> wrote:

Hello,


I have *.hdf5 data files recorded with g.Recorder (generated by USBamp, g.tec 
GMBH) countaining a H5T_IEEE_F32LE data set with 2 channels values intermixed: 
each even index are positive values and odd are negative ones. So even values 
correpond to the first channel and odd to the second. So far so good, however, 
the mean values of each channel do not correspond to valid physiological 
measures. So I'm looking for the value  (or algorithm) allowing to reajuste the 
values for each channel, but wasn't able to find it. Do the value 
transformation for each channel is always the same for H5T_IEEE_F32LE when 
storing two channels or this is determined in the g.tec device and so is 
independent of the hdf5 file format?


Some help will be welcome, many thanks!


Florian

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