From: Dave (dfisher_at_pophost.com)
Date: 2002-02-26 14:33:39
On Tue, 26 Feb 2002 12:29:46 +0100, Joerg Hansmann wrote:
>>I looked at the Cool Edit site and it seems they want $76 for the small version and $400
>>for the Pro version. Which version do you have and will the $76 one work for me?
>
>The screenshots I have posted are from the small version.
>
>However the Pro - version seems to be able to display multiple channels:
>http://www.psychosensory.com/pies-session/cool-edit-session-screen-labeled.jpg
>
>(perhaps Dave can provide some information about the Pro - version ...)
I use the pro version because of the 64 multitrack session editor. You can
purchase an addon for the 2000 version for $50 which will give you a 4 track
editor, but I felt that it might constrain what I wanted to do. Now that I
have been using it, it seems that I rarely go over 4 tracks after all. But I
think the FFT analysis is the same in both packages, so the 2000 should
suffice.
>
>>Can
>>this display show frequencies as low as 0.1 Hz ?
>
>Yes. (Depending on set FFT bands)
>
>>How would I feed my EEG data into the
>>Cool Edit package?
>
>Cool Edit can read /write many standard sound formats and different raw data
>formats:
>
>e.g.
>ASCII (with one sample value per line)
>8 bit and 16 bit PCM raw (mono, stereo, diffenet byte orders and arbitrary sample rates).
>From their help file:
ASCII Text Data (.TXT)
Data can be read to or written from files in a standard text format, with each
sample separated by a carriage return and channels separated by a tab
character. Options allow data to be normalized between -1.0 and 1.0, or written
out and read in raw sample values. An optional header can be placed before the
data. If there is no header text, then the data is assumed to be 16-bit signed
decimal integers. The header is formatted as KEYWORD:value with the keywords
being: SAMPLES, BITSPERSAMPLE, CHANNELS, SAMPLERATE, and NORMALIZED. The
values for NORMALIZED are either TRUE or FALSE. For example,
SAMPLES: 1582
BITSPERSAMPLE: 16
CHANNELS: 2
SAMPLERATE: 22050
NORMALIZED: FALSE
164 <tab> -1372
492 <tab> -876
etc...
I exported some EEG data in ASCII format for Jim P this morning, and was able
to read it into Cool Edit. I did not include any of the header information as
in the above example, so it prompted me for the sample rate and number of
channels. Funny thing is that the ProComp+ is reputed to send 256 samples/sec
of EEG data, and yet the ASCII dump through the software only generated 4
samples/sec. So when I opened this file in Cool Edit, I selected mono for the
number of channels, 4 as a sample size, and the time marks match what I see in
ProComp's EEG software.
>>Do I need a translator of some sort?
>
>IMO : yes. You will need a little program, that extracts your channel data.
I agree. Since this is a sound editor, all the file formats relate to various
sound recording formats.
>One further disadvantage of the cooledit waveform display that should be mentioned:
>Cooledit uses some form of interpolation between the samples that give nasty overshoots
>in the display. (However the color setup can be chosen in a way that lets you clearly
>see, what are real samples and what is interpolated)
I haven't seen it do this. Perhaps I've been lucky. :) Under what conditions
would it interpolate the values? I could see it doing this if you inserted
some values into the middle of a stream, but otherwise, I figured that it would
display the straight waveform without interpretation. I looked for a color
option that would make a distinction between the two (real vs. interpolated),
but could not find one.
Also--Jim M. Syntrillium may still offer a try-before-you-buy deal. What
would happen is that when you ran the software during the trial period, it
would ask you what features you wanted active, and would limit you to a set
number of features (2 or so; I forget how many). In this way you can download
and install it and see if it will provide you with the functionality you need.
Of course, if you are only doing FFT anaylsis, the trial version may be *all*
you need!
Dave.
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