[MEI-L] Time representation in MEI and EDTF

Benjamin Wolff Bohl bohl at edirom.de
Fri Apr 5 08:41:22 CEST 2013

Hi Don,
took me a while to look what this interesting email subject was all 
about and it is really interesting! The notions of implementing 
certainty in a timeformat that EDTF puts forward is certainly very 
promising for dating issues, although this might be conflicting with the 
possibilities metadata formats already give. An implementation of a 
fixed EDTF standard in a format already providing possibilities like 
certainty/uncertainty, not-before, not-after, etc. will result in even 
more ways of encoding the same thing, as metadata formats certainly 
won't easily drop such features.
If it comes to music the decimal digits of seconds might not be 
interesting for source dating but for metadata of audio files, CDs, LPs 
or any other sound carrier. Also in things like performance analysis, or 
semiautomatic audio data analysis or some MIR issues, precise timecodes 
are essential.
 From my audio engineering background I'd even say that you'll need at 
least 3 digits decimal places. In binaural tests 10ms delay between the 
same signal on both ears have been proved to be audible by almost 
everybody. Trained audio engineers / musicians (the best of wich were 
percussionists) can hear differences smaller than 5ms, even a 1ms delay 
can be heard.
Now for example describing digitized audio material, I don't see why one 
should not be able to describe sample positions, e.g. hh:mm:ss:sample.
With audio samplerates of standardized sound carriers ranging as high as 
192kHz this would mean a sample is something like 0.0052 milliseconds!
Nevertheless there are phenomena on intersample level which lead DAW 
(Digital Audio Workstation) plugin developers to start oversampling in 
their software.
The more technical we get on this the smaller will the time units get ;-)

To cite someone fequently posting here:
"just my two cents"


Am 26.02.2013 04:22, schrieb Byrd, Donald A.:
> All--
> I've been thinking a lot recently about representing time in extremely 
> general ways, and I've gotten involved in discussion of EDTF, an 
> "Extended Data Time Format" under development by the bibliographic 
> community (http://www.loc.gov/standards/datetime/). In many ways, EDTF 
> is "extended" compared to, say, ISO 8601, but the current draft is 
> actually more limited in at least one important way: its maximum 
> precision is a second, while both 8601 and XSD allow seconds with 
> several -- quite possibly an unlimited number of -- decimal places.
> I'm telling you this because I'd like to see a musicologist or two 
> involved in the EDTF discussion. Furthermore, I'd like to see support 
> for seconds with multiple decimal places added to EDTF, and the EDTF 
> coordinator at the Library of Congress seems willing to add it _if_ 
> someone gives him a realistic use case. I'm not sure I have a 
> realistic bibliographic use case, but I'll bet some of you do!
> Also, a side question. The MEI docs keep referring to "standard ISO 
> form" for dates and times. What is "standard ISO form"? I can't find 
> an explanation. Does that mean ISO 8601?
> --Don
> -- 
> Donald Byrd
> Woodrow Wilson Indiana Teaching Fellow
> Adjunct Associate Professor of Informatics
> Visiting Scientist, Research Technologies
> Indiana University Bloomington
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