For each slide set created, the Web Conferencing Server saves two encrypted XML files. The encryption algorithm is AES and the encryption key is the master key stored in the conference.xml file. Because the files are encrypted, their file names use an .exml file name extension.

Each slide set has a unique identifier. The slide set file names are created using the following patterns:

       set- <unique_identifier> .exml and set-s- <unique_identifier> .exml

For example, for a slide set with the unique identifier abc, the file names are set-abc.exml and set-s-abc.exml.

The content of the two files is the same. The second file is provided for backup purposes. When the Web Conferencing Server needs to save new changes in the slide set with the unique identifier aaa, the server opens the first file—set-aaa.exml—and attempts to save the changes to that file. If the original write operation succeeds, the Web Conferencing Server creates a copy of set-aaa.exml and renames the copy slide-s-aaa.exml. If the write operation fails, the Web Conferencing Server deletes set-aaa.exml, creates a copy of set-s-aaa.exml, and renames the copy set-aaa.exml.

The following figure shows the logical flow of the update operation.

The update procedure for slide sets is called every five minutes. This value is hard coded and cannot be changed. If an update operation fails, the changes made to a slide set in the past five minutes are not saved. If the Web Conferencing Server stops running during this period, changes to the slides can be lost. However, the Web Conferencing Server continually tries to update the files every five minutes. As a result, if one attempt fails, the Web Conferencing Server can attempt to save the content later.

Each slide set file contains the XML serialization of the data required to recreate the slide set content. The generic layout for this XML is as follows:

  • A root node that contains information about the slide set (for example, the name, creator, and time when the slide set was created).

  • A child node for each slide in the slide set. This node contains the information about the slide (for example, the name, creator, time when the slide was created, type of slide, a link to the original document, and a link to the images representing the slide).

  • Based on the type of slide, there can be child nodes. For example, there can be a child node for the annotations in a PowerPoint slide or a child node for the question and answer choices in a poll slide.

The file is a snapshot of the current content for a given slide set. The file does not store historical information such as deleted slides or the values for attributes before they have been updated.

There are two types of slides:

  • Slides for which all the slide content is shared between Web Conferencing Server and meeting clients using only the PSOM channel. The following table lists the slide types for which all content is shared over PSOM.

    Slide Type Slide Content Shared over PSOM

    Web slide

    Name, URL

    Poll Slide

    Name, question, answer choices

    Text Slide

    Name, content

    Application Sharing Slide

    Name, type of sharing (that is, Desktop or Application), color depth, process ID
  • Slides for which some part of the content is shared between the Web Conferencing Server and meeting clients over PSOM and some other part of the content is shared between the Web Components Server and meeting clients over HTTPS. The following table lists the slide types for which content is partially shared over PSOM and partially shared over HTTPS.

    Slide Type Slide Content Shared over PSOM Slide Content Shared over HTTPS

    Whiteboard

    Name, annotations

    Background image (white rectangle)

    Snapshot

    Name, annotations

    Background image (the desktop screen capture from the conference presenter)

    PowerPoint

    Name, annotations

    PNG files for the large slide image and for the slide thumbnail; original PPT document

    Word Document

    Name, annotations

    PNG files for the big image and for thumbnail;

    original MDI document

    Multimedia

    Name

    Original multimedia file; the chunk files

For slides for which some content is shared over PSOM and some is shared over HTTPS, the content that is shared over HTTPS is stored in the conference content folders. The conference metadata file for the slide set stores only the link to the conference content file and the encryption key.

For example, if you have a slide generated from a PowerPoint slide, under the XML node for that slide you find the:

  • Randomly generated name for the original uploaded PPT file.

  • Encryption key for the PPT file.

  • Randomly generated name for the large image of the slide in PNG format.

  • Encryption key for the PNG file.

  • Randomly generated name for the thumbnail image of the slide in PNG format.

  • Encryption key for the PNG file.

You can use the names of these PPT and PNG files to search for the slide content in the conference content folders.

Metadata File for Poll Slide

The following is an example of the XML content for a Poll slide.

Copy Code 
<poll-slide 
   name="[ Poll 1 ]" 
   recording-id=""
   createdby="sip:vw01@rtcdev.nttest.contoso.com [vw01]">
   <question>What day is today?</question>
   <choice>MON</choice>
   <choice>TUE</choice>
   <choice>WED</choice>
   <choice>THU</choice>
   <choice>FRI</choice>
   <choice>SAT</choice>
   <choice>SUN</choice>
</poll-slide>

Metadata file for Text Slide

The following is an example of the XML content for a Text slide.

Copy Code 
<text-slide 
   name="[ Text Slide 1 ]" 
   recording-id="" 
   createdby="sip:vw01@rtcdev.nttest.contoso.com [vw01]"
>
   <current-text>
   This is the content of a text slide I've just typed
   </current-text>
</text-slide>

Metadata File for Web Slide

The following is an example of the XML content for a Web slide.

Copy Code 
<web-slide 
   name="[ Web Slide 1 ]" 
   recording-id="" 
   createdby="sip:vw01@rtcdev.nttest.contoso.com [vw01]" 
   url="http://microsoft.com">
</web-slide>

Metadata File for Whiteboard Slide

The following is an example of the XML content for a Whiteboard slide.

Copy Code 
<image-slide 
   name="[ White Board 1 ]" 
   recording-id="" 
   createdby="sip:vw01@rtcdev.nttest.contoso.com [vw01]" 
   image-width-attr="704" 
   image-height-attr="528" 
   page-number="-1" 
   rich-slide-type="Whiteboard" 
   thumbnail-aspect="1.33333337">
   <ann 
	COLOR="0" 
	AUTHOR="vw01" 
	TYPE="1" 
	recording-id="">
	 
01000000000a0075007a00af007100cc009c00c000ba009d00b0009b009d00f40084011400980116009901160099
   </ann>
   <ann 
	COLOR="0" 
	AUTHOR="vw01" 
	TYPE="23" 
	recording-id="">
	17000000009700fa01090144
   </ann>
</image-slide>

Metadata File for Snapshot Slide

The following is an example of the XML content for a Snapshot slide.

Copy Code 
<image-slide 
   name="[ Snapshot 1 ]" 
   recording-id="" 
   createdby="sip:vw01@rtcdev.nttest.contoso.com [vw01]" 
   image="x8d51284585d1.epng" 
   key="a51fe0f3e26813761e12435a9c2c5d89" 
   image-filesize-attr="52865" 
   image-width-attr="388" 
   image-height-attr="369" 
   page-number="-1" 
   rich-slide-type="Image" 
   thumbnail-image="xe31d11b0506d.epng" 
   thumbnail-key="a51fe0f3e26813761e12435a9c2c5d89" 
   thumbnail-aspect="1.0" 
   compliance-image="xcb4de1d7b784-aae.png">
   <ann 
	COLOR="0" 
	AUTHOR="vw01" 
	TYPE="1" 
	recording-id="">
	 
01000000000a0075007a00af007100cc009c00c000ba009d00b0009b009d00f40084011400980116009901160099
   </ann>
   <ann 
	COLOR="0" 
	AUTHOR="vw01" 
	TYPE="23" 
	recording-id="">
	17000000009700fa01090144
   </ann>
</image-slide>

Metadata File for Word Document Slide

The following is an example of the XML content for a Word document slide.

Copy Code 
<image-slide 
   name="Page 1" 
   slideset-name="test.txt" 
   recording-id="" 
   createdby="sip:vw01@rtcdev.nttest.contoso.com [vw01]" 
   image="xebc7f400248d.epng" 
   key="ce3de85a37a8a6fc6b3b702b70a1a925" 
   image-filesize-attr="6778" 
   image-width-attr="816" 
   image-height-attr="1056" 
   document="x9838edc7b0d2.emdi" 
   document-key="8ca685d4bcfb9afe94cc27ea4bd0a2e1" 
   document-filesize-attr="1537" 
   rich-slide-type="Modi" 
   thumbnail-image="x908006115ceb.epng" 
   thumbnail-key="40d224ca035ee8f77ba9c7342da17b1b" 
   thumbnail-aspect="0.772727251" 
   thumbnail-filesize-attr="748" 
   compliance-image="xf3ae96bf86cd-aag-pngimage0.png" 
   compliance-document="xbe356497761b-aag-x.mdi">
</image-slide>

Metadata File for Application Sharing Slide

The following is an example of the XML content for an Application Sharing slide.

Copy Code 
<demo-slide 
   name="Command Prompt - vw01" 
   recording-id="" 
   createdby=sip:vw01@rtcdev.nttest.microsoft.com [vw01]
   shareProcInfo=sip:vw01@rtcdev.nttest.contoso.com -
01C7E74B9137AC70
   shareHwnd="262300" 
   shareSpeed="1" 
   sharePid="4592"
   slideHotKey="19"
   slideColor="24" 
   shareTitle="Command Prompt" 
   slideCtrl="1" 
   shareType="1">
</demo-slide>