Time zone ambiguity

Opstad, Dave dave.opstad at monotype.com
Fri Aug 29 17:46:10 CEST 2014

There is an ambiguity in the original TrueType spec that has, unfortunately, continued right up to this latest OFF spec. Specifically, in the 'head' table, the "modified" and "created" fields are listed as 64-bit counts of seconds since an epoch of "12:00 midnight, January 1, 1904". Unfortunately no time zone is specified, and this has led to ambiguity where a font is modified by some tool in, say, Germany, and is then run through validation code in California, where a complaint is raised that "the modification date is in the future".

I wonder if it would be possible to include a clarifying note in the spec that GMT/UTC is the time zone of choice for these fields?


From: <'Levantovsky>, "Vladimir' vladimir.levantovsky at monotype.com<mailto:vladimir.levantovsky at monotype.com> [mpeg-OTspec]" <mpeg-OTspec-noreply at yahoogroups.com<mailto:mpeg-OTspec-noreply at yahoogroups.com>>
Reply-To: "Levantovsky, Vladimir" <Vladimir.Levantovsky at monotype.com<mailto:Vladimir.Levantovsky at monotype.com>>
Date: Monday, August 25, 2014 9:24 AM
To: "mpeg-OTspec at yahoogroups.com<mailto:mpeg-OTspec at yahoogroups.com>" <mpeg-OTspec at yahoogroups.com<mailto:mpeg-OTspec at yahoogroups.com>>
Subject: [mpeg-OTspec] AHG Kick-off and the new mandate

Dear AHG members,

I am happy to report that the text of the 3rd edition of ISO/IEC 14496-22 “Open Font Format” standard has been promoted to Draft International Standard stage and the ballot is now published. The text has been made public and can be downloaded for review using the following link:

The AHG mandate is “to study the DIS of the ISO/IEC 14496-22 3rd edition and solicit technologies to further improve it”. I would like to ask you to review the text and provide your suggested changes which can be incorporated as ISO ballot comments. At this stage, we can only suggest comments that incorporate clarifications and improvements to what is already included in the standard, proposals for new technologies can be considered as future new work items and would require an amendment.

Thank you very much for your contributions!

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