IFX Mail Archive: Re: IFX> RE: New Compression Keywords

IFX Mail Archive: Re: IFX> RE: New Compression Keywords

Re: IFX> RE: New Compression Keywords

From: Carl Kugler (kugler@us.ibm.com)
Date: Tue Oct 30 2001 - 11:26:44 EST

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    Of course, compression can also be indicated at the HTTP layer with the
    "content-coding" header. IANA maintains a registry of content-coding value
    tokens.

            -Carl

    Sent by: owner-ifx@pwg.org

    To: "'Hastings, Tom N'" <hastings@cp10.es.xerox.com>, "Bergman, Ron"
    <Ron.Bergman@Hitachi-hkis.com>
    cc: "'ifx@pwg.org'" <ifx@pwg.org>
    Subject: IFX> RE: New Compression Keywords

    Tom,

    I agree that these are commonly used within TIFF and you are correct that
    they are not really required to support IPPFAX. However, the compression
    methods can be used independently from TIFF and that is the situation that
    I
    need to cover. We do have products that support some of these compression
    methods and I believe that they should be all registered for use with IPP.

    I would like to reopen this issue as a proposal to register these keywords
    for the IPP compression attribute.

                    Ron

    -----Original Message-----
    From: Hastings, Tom N [mailto:hastings@cp10.es.xerox.com]
    Sent: Friday, October 26, 2001 5:46 PM
    To: Bergman, Ron
    Cc: 'ifx@pwg.org'
    Subject: RE: New Compression Keywords

    Ron,

    Sorry you were unable to attend the meeting.

    We did discuss your suggestion to add a bunch of keywords to the IPP
    "compression" and "compression-supported" attributes for MR, MH, MMR, etc.
    We decided that the "compression" IPP operation attribute is referring to
    the compressions of the overall print data stream, not the encoding methods
    within a document format that are used to reduce the size. We think that
    your list are all examples used within TIFF-FX and so should not be
    keywords
    used in the "compressions" IPP operation attribute. In fact, if a sender
    were to encode a TIFF-FX file using one of these encodings, the file would
    actually grow larger, since the encoding had already been applied
    internally.

    An IPPFAX client can determine which encodings are used (MR, MH, MMR, etc.)
    for the image/tiffx MIME type by querying the Printer's
    "ippfax-uif-profiles-supported". Each profile requires certain encodings.
    If an implementation uses additional encodings above the REQUIRED ones for
    a
    profile, then it MUST indicate them in the CONNEG string value of the
    Printer's "ippfax-uif-profile-capabilities" attribute, so that the client
    can discover them.

    OK?

    Thanks,
    Tom

    -----Original Message-----
    From: Bergman, Ron [mailto:Ron.Bergman@Hitachi-hkis.com]
    Sent: Tuesday, October 16, 2001 13:37
    To: Tom Hastings (E-mail)
    Cc: 'ifx@pwg.org'
    Subject: New Compression Keywords

    Tom,

    For support of IPP FAX, the attributes "compression" and
    "compression-supported" must have the following new keywords defined:

    1. mh (modified Huffman)
    2. mr (modified READ)
    3. mmr (modified modified READ)
    4. jpeg (Joint Photographic Experts Group)
    5. jbig-lossless-bw (Joint Bi-level Image Group, black and white)
    6. jbig2-lossy-bw
    7. jbig2-lossless-bw
    8. jbig2-lossy-color
    9. jbig2-lossless-color

    I am not sure if this covers all the possibilities. I propose that this be
    a discussion topic next week.

    My travel request was not approved, so if you could lead this discussion, I
    would appreciate it.

                    Ron



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