CFV: eXIf 2017-0119
Glenn Randers-Pehrson <[email protected]>
| Newsgroups | gmane.comp.graphics.png.general |
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CALL for VOTE eXIf 2017-0119 ftp://ftp.simplesystems.org/pub/png-group/documents png-proposed-eXIf-chunk-2017-0119.html Glenn Randers-Pehrson <[email protected]> also available at http://www.simplesystems.org/png-group/proposals/eXIf/png-proposed-eXIf-chunk-2017-0119.html http://www.simplesystems.org/png-group/proposalseXIf/png-proposed-eXIf-chunk-2017-0119.txt This is a call for votes on the PNG proposal eXIf 2017-0119 To vote on this proposal, send a message to png-mng-misc-TtF/[email protected] The subject line of your message must contain the words VOTE YES|NO|ABSTAIN: eXIf 2017-0119 and must NOT contain the string "Re:" (i.e. do not try to cast your vote by "replying" to this message. You must manually construct the proper subject line). The body of your message must contain the following five lines, which must appear first in the message. YES | NO | ABSTAIN eXIf 2017-0119 ftp://ftp.simplesystems.org/pub/png-group/documents png-proposed-eXIf-chunk-2017-0119.html Your Name <yourusername at yourhost.yourdomain> After these five lines you can add an explanation of your vote, if you desire. Providing the rationale for a NO vote is particularly encouraged. The voting period closes exactly two weeks after the time that this message was received by the png-mng-misc list server (png-mng-misc-TtF/[email protected]) You can change your vote by submitting a new message. Only the last message sent by you and received by the png-mng-misc list server prior to the close of the voting period will be counted. Your messages can be sent from different e-mail accounts, but the fifth line of all of your messages, containing your name and your preferred e-mail address, must be identical. You are eligible to vote if your earliest message to png-mng-misc or png-mng-implement was received at least 180 days earlier than the close of the voting period. For your convenience, a copy of the proposal follows. regards, Glenn Randers-Pehrson PNG Proposed eXIf chunk, draft 20170119 File: png-proposed-eXIf-chunk-20170119.html Status of this Memo This document is an informal draft of the PNG development group. Comments on this document can be sent to the PNG specification maintainers at [email protected] [1]. Distribution of this memo is unlimited. Initial proposals were in the png-mng-misc mailing list, January 2017. At present, the latest version of this document is available on the World Wide Web from ftp://ftp.simplesystems.org/pub/libpng/png-group/documents/ [2]. Notices Copyright © 2017 Glenn Randers-Pehrson Permission is granted to copy and distribute this document for any purpose and without charge, provided that the copyright notice and this notice are preserved, and that any substantive changes or deletions from the original are clearly marked. Abstract This document describes a special-purpose chunk type that has been proposed for use in various PNG (Portable Network Graphics) and related multi-image applications. It has not yet been approved for registration by the PNG developers, and therefore is experimental and its format is subject to change. The proposed chunk is "eXIf" (an unregistered name that can be used in test implementations is "exIf"). Caution: the third letter in the chunk name is an uppercase "i", not a lowercase "L". PNG exIf (raw Exif) proposal It is proposed to add the following section to the document "Extensions to the PNG 1.2 Specification, Version 1.4.0" 3.7. eXIf Exif (Exchangeable Image File) profile The four-byte chunk type field contains the decimal values 101 88 73 102 (ASCII "eXIf") The data segment of the eXIf chunk contains an Exif profile in the format specified in "4.7.2 Interoperability Structure of APP1 in Compressed Data" of [CIPA DC-008-2016] except that the JPEG APP1 marker, length, and the "Exif ID code" described in 4.7.2(C), i.e., "Exif", NULL, padding byte, are not included. It begins with either "II" or "MM", depending upon the byte order used. At most one eXIf chunk shall occur in a PNG datastream. There are no ordering constraints upon the position of the eXIf beyond those imposed by the PNG specification, i.e., if present, the eXIf chunk may appear anywhere between the IHDR and IEND chunks except between IDAT chunks. See ISO 12234 (the XMP standard): [3]https://www.iso.org/obp/ui/#iso:std:iso:12234:-3:ed-1:v1:en CIPA DC-010-2012, Exif 2.3 Metadata for XMP. Available at: [4]http://www.cipa.jp/std/documents/e/DC-010-2012_E.pdf CIPA DC-008-translation-2012, Exchangeable image file format for digital still cameras: Exif Version 2.3. Available at: [5]http://www.cipa.jp/std/documents/e/DC-008-2012_E.pdf Description of the Exif file format, (based on Exif Version 2.1), TsuruZoh Tachibanaya, May 28, 1999, [6]https://www.media.mit.edu/pia/Research/deepview/exif.html eXIf Security considerations It is proposed to add the following clause to Section 7 (Security Considerations) of the "Extensions to the PNG 1.2 Specification, Version 1.4.0" document: The eXIf chunk contains metadata concerning the original image data. This data may not apply or may no longer apply to the PNG image data. Where conflicting information is present in other chunks in the stream that data shall be assumed to be correct unless it can be determined to be incorrect. Information relevant only to the original JPEG or TIFF encoding shall be ignored. Contributors Contributors to discussion on the png-mng-misc list * John Bowler * Adam Costello * Glenn Randers-Pehrson * Nancy M. Randers-Pehrson * Jason Summers * Cosmin Truta * Willem van Schaik Editor * Glenn Randers-Pehrson, [email protected] End of PNG eXIf Chunk Proposal. Expires 14 August 2017. References 1. mailto:[email protected] 2. ftp://ftp.simplesystems.org/pub/libpng/png-group/documents/ 3. https://www.iso.org/obp/ui/#iso:std:iso:12234:-3:ed-1:v1:en 4. http://www.cipa.jp/std/documents/e/DC-010-2012_E.pdf 5. http://www.cipa.jp/std/documents/e/DC-008-2012_E.pdf 6. https://www.media.mit.edu/pia/Research/deepview/exif.html ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, SlashDot.org! http://sdm.link/slashdot _______________________________________________ png-mng-misc mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/png-mng-misc