Windows Live Photo & Video Blog

Official blog for the Windows Live Digital Memories Experience team

August, 2006

  • Windows Live Photo & Video Blog

    Metadata and the Windows Vista Photo Gallery

    • 23 Comments

    If you have ever applied a tag to a photo, given it a star rating, or changed the date or time it was taken, you’ve edited the metadata on the photo. The term metadata literally means “data about data”. Your photos are considered “data”, so metadata about your photos is simply information that further describes your photos.

    The Windows operating system has always had mechanisms for storing and displaying metadata. For example, here is some of the information available for photos in Windows XP:

    • File Name
    • File Size
    • File type
    • Date last modified
    • Etc.

    Windows Vista makes some improvements to the metadata system for photos. For example, here is some of the new information available in Windows Vista:

    • Tags
    • Date Taken
    • Rating
    • Caption
    • Image Resolution
    • Camera make/model
    • Shutter speed
    • Etc.

    Some of this information is written to the photo by your camera (e.g. shutter speed, date taken, camera make/model). Some of it is added by you in an application like the Windows Vista Photo Gallery (e.g. tags, captions, and ratings).

    In the past, you may have used third-party image management applications that allowed you to add tags (or other metadata) to your photos, only to find out later that those tags were locked in a private database that only that application could read. This makes it inconvenient to share your photos (or back them up), since the metadata didn’t travel with the file. In Windows Vista, our goal is “the truth is in the file”. That means that metadata you apply to your photos is part of the photo, and available to any application that knows how to read it. But how do we accomplish that?

    EXIF, IPTC, and XMP – oh my!
    There are a number of competing standards for imaging metadata. That is, different ways of reading and writing metadata for photos. One of the biggest standards, EXIF, is commonly written to photos by most cameras, but has many limitations. It’s somewhat antiquated, fragile, not very flexible, and doesn’t support international languages like Japanese very well. IPTC is a standard that is used pretty widely in journalism applications, but is undergoing a transformation towards an XMP-based system.

    XMP is an extensible framework for embedding metadata in files that was developed by Adobe, and is the foundation for our “truth is in the file” goal. All metadata written to photos by Windows Vista will be written to XMP (always directly to the file itself, never to a ‘sidecar’ file). When reading metadata from photos on Windows Vista, we will first look for XMP metadata, but if we don’t find any, we’ll also look for legacy EXIF and IPTC metadata as well. If we find legacy metadata, we’ll write future changes back to both XMP and the legacy metadata blocks (to improve compatibility with legacy applications).

    Hurry up and wait
    It can be time consuming and resource intensive to read and write large image files. Because of this, The Windows Photo Gallery does all of its file activity in the background. When you query or tag photos in the Gallery, the instantaneous performance you’re seeing is the result of a database that caches metadata to provide a fast user experience.

    Although you’re able to tag thousands of photos and move on immediately, the reality is that those files will slowly be updated in the background. If you have tagged a bunch of files, those tags will not be visible to other applications until the Gallery has finished writing to those files. There is a small indicator in the bottom left hand corner of the application to let you know what the Gallery's metadata read/write status is.

    Hover your mouse over the small blue icon below the tree when it appears to see a tooltip with the following information:

    • Number of tag updates remaining (how many files the Gallery needs to read tags/metadata from)
    • Number of file updates remaining (how many files the Gallery needs to write tags/metadata to)
    • Number of thumbnail updates remaining (how many thumbnails the Gallery needs to generate from files)

    When the little blue icon disappears, it means the Gallery’s database and the file system are in sync. If you still run into files that are out of sync…

    Your mileage may vary
    Although our goal is for “truth in the file”, we know that we won’t be able to achieve it 100% of the time for all files. There are some cases where metadata writeback is impossible, so we do the best that we can. Some of the cases where we can’t write back metadata include:

    • Insufficient permissions to write to the file
    • File type (or codec) doesn’t support metadata writeback (e.g. BMP, PNG, GIF, MPEG, etc.)
    • Corruption in the file (badly formed metadata, etc.)
    • File is locked for writing by another application

    In these cases, the Photo Gallery will write the tags (or other metadata) to its own database, but since it is not in the file, other applications (and other parts of Windows) will not have access to the metadata. Other parts of Windows (e.g. Explorer, the Photo Viewer) may not allow you to write back metadata at all if it cannot be written to the file immediately.

    The Gallery does retry writeback operations several times before giving up. Every time the Gallery starts up, it will retry files that it couldn’t write in previous sessions. So if you discovered that your tags weren’t getting written back to your files because they were marked read-only, simply clear the read-only flag, and restart the Gallery. This should cause all of your tags to get written to your files.

    We will be posting more extensive documentation on MSDN in the coming weeks. Watch this space for an update!

    - Scott Dart (Program Manager)

  • Windows Live Photo & Video Blog

    Windows Vista Slideshow

    • 18 Comments

    Ever wonder what hides behind the candy-like blue button? My name is Karen Wong, and I'm a Program Manager on the Windows Vista Photo Gallery. My team created the experience behind this blue button - the Windows Vista Slide Show. This is the place to enjoy your photos and videos in their full-screen glory; or to set them against a background that suits the occasion.

    So what are some of the big changes from the XP Slide Show?  First off, the Vista slideshow can play photos AND videos.  Previously in XP, it was not possible to combine photos and videos in a single Slide Show. If you’re like me, you’ll take a couple of short clips in addition to your larger set of photos at any given event. Now there’s a one-stop shop to viewing everything you uploaded.

    Next, we’ve created a set of ‘themes’ that provide different ways for you to enjoy your photos.  The themes are designed to vary in the number of photos/videos you see on screen, the look-and-feel of the background; as well, we’ve spiced some themes up to include some new animation effects.

    We expect our users to have a wide variety of photos from a diverse range of events, activities, and special occasions. Our themes try to address this broad range of subject matter, as we know that different photos can be complimented with the right ‘mood’ in a theme. 

    Themes are organized in the slideshow menu in groups: the top 3 groups display photos/videos at full-screen. The bottom group displays photos/videos in a single or multi-layout format, with themed backgrounds. Some of the themes in the last group also include the new animated effects. 

    But not too fast. Although we’re jazzed about these new themes, we still love the simplicity of the XP slideshow.  So guess what?  We kept it in. You’ll find the XP slideshow under the ‘Classic’ theme - it plays photos only, with no fancy backgrounds or effects.

    One caveat: cool Slide Shows need the right hardware.  You’ll need a minimum level of graphics support (i.e. video card) to get the new and improved Slide Show experience. The quickest way to find out whether you’re ‘Slide Show Ready’ is to check your Windows Experience Index (Start Menu | Computer | System Properties). On par with the requirements to run Aero Glass, you’ll need a ‘Graphics’ score of at least 3.0. 

    Power User
    If your graphics score isn’t at least 3.0, you can still get the full set of themes (with the Premium or Ultimate SKU) by setting a regkey. Keep in mind that there are no guarantees that they will run well!

    Here is the info you need to set the regkey:
    Key path is HKCU\Software\Microsoft\Windows Photo Gallery\SlideShow.
    Type = DWORD Value
    Name = WinSATScore
    Value = 300

    - Karen Wong, Program Manager

  • Windows Live Photo & Video Blog

    Photosynth Technology Preview

    • 6 Comments

    I’m Bryan Ressler, a Software Engineer on the PIX Team. If you’ve been reading this blog, you’ll know that the PIX team is responsible for the photo and imaging user experiences in Windows Vista, as well as Microsoft’s Digital Image Suite product line. PIX also maintains a small incubation team, called PIX Labs, whose charter is to investigate photo-related technologies, create prototype software, and learn from those prototypes to help shape the roadmap for consumer photo experiences. I’m on the PIX Labs team, and I’d like to share some details about one of our exciting projects.

    Photosynth – What is it?
    Photosynth is based on research carried out by University of Washington's Noah Snavely and Steve Seitz with MSR Principal Researcher Rick Szeliski. They envisioned and prototyped a system by which a collection of photos could be processed into an immersive, three-dimensional viewing environment. The team's primary research is being presented this week at the international SIGGRAPH computer graphics conference.

    PIX Labs saw Photo Tourism, since renamed Photosynth, as a powerful new way for everyday photographers to enjoy their photos, and saw lots of potential beyond that. So PIX Labs joined into a collaboration with Live Labs’ recently-acquired Seadragon team to create a compelling technology preview based on the original Photo Tourism idea.

    The resulting application provides a “point cloud” 3D model of the scene along with the 3D locations of all the cameras (the small orange pyramids in the picture). The photos in the collection can be “projected” onto the 3D model (like a slide projector). Because so much is known about the relationships between the photographs, easy navigation mechanisms are provided, such as “show me an image to the left of this one” (the arrows around the outside of the window), and “show me the images that are similar to this one,” as shown in the “splatter” view here.

    Additionally, because Photosynth was built atop Live Labs’ Seadragon technology, with Photosynth you can zoom in to arbitrarily high resolutions. Even if every photo in the collection is 12 megapixels or more, all that information is preserved.

    How It Works
    Photosynth collections start with a set of photographs of roughly the same subject, such as a place, object, or monument. The photographs might have been taken all at once by the same photographer, or they might be a disparate set of pictures collected from different photographers at different times. The images are then processed by a preprocessor program that identifies “features” in the photographs – identifiable points in each image. (This picture shows a photo with some of its feature points superimposed.)

    Once features have been identified for all the photos, the preprocessor finds the feature point correspondences between all the images in the set. In the process, the software uses a computer vision technique called “structure from motion” to determine the three-dimensional position of each feature point. This also allows the program to determine the relative position in 3D from which each photograph was taken.

    The point cloud you saw in the first picture is simply the complete set of 3D feature points of all the photos in the collection. It helps provide context for the individual photos in the collection. (This image below shows part of a point cloud, some of the camera locations, and the “projection” of one of the cameras that indicates what part of the model was photographed.)

    It turns out that by using this technique quite a bit of information can be gleaned from the photo set, all automatically. And because the software knows how the photographs fit together, unique navigational aids are built into Photosynth to allow the user to navigate left, right, up, down, in, and out from the currently viewed photograph. As a result it is very easy to take “virtual tour” of a place, letting you see a view not too different from what you’d experience strolling around the location in person. Thus we see Rick’s original “photo tourism” dream realized.

    What’s Next
    What you see here is a technology preview. In the short term, we’re working hard to get a public release ready. But what’s really exciting is to think where a technology like this could take us.

    What if all the world’s billions of images were woven into a single gigantic Photosynth collection? What if you could visit any place, anywhere, through the eyes of the countless people who have photographed that place in the past? What if you could take a trip through time, seeing how a place changed as time went by?

    Those are a few of the big-picture projections of where we’re going with Photosynth. But in the shorter term, here are a couple practical examples of benefits we could see from this technology. Someone takes a picture of Nelson’s Column in the middle of Trafalgar Square in London, tags that photo “Nelson’s Column,” and adds it to the web Trafalgar Square Photosynth collection. Later, when you visit London, you upload your photos of Trafalgar Square to the same web collection. Since the software can “see” that some of your pictures contain Nelson’s Column, those pictures can be automatically tagged with the proper metadata -- along with your other sights in London. This makes your photos immediately more searchable and thereby more valuable.

    Another example: You walk up to the Trevi Fountain in Rome and wonder the name of the big guy in the middle of the fountain. You point your camera phone at it, snap a picture, and send it to a web service that uses the photo, perhaps your GPS or cell-triangulated location, and a Photosynth collection of the Trevi Fountain to determine the content of your photo. A moment later you receive an SMS message: “Neptune, god of the sea” along with a set of reference links.

    I hope you share my enthusiasm for this technology. Photosynth is just one example of Microsoft innovation aimed at creating richer, more fulfilling experiences for real-world computer users like you and me. Keep an eye on the PIX Blog for more information on Photosynth and its upcoming public Tech Preview release. In the mean time, check out Live Labs’ Photosynth site and be sure to watch the videos of Photosynth in action.

    - Bryan Ressler (Software Engineer)

  • Windows Live Photo & Video Blog

    Metadata Questions and Answers

    • 6 Comments

    We’ve received a number of great questions and feedback from the metadata blog post last week. Since the answers to those questions are likely of interest to many people, we decided to simply post a follow-up with answers to some of the frequently asked questions.

    Is Windows XP metadata compatible with Windows Vista metadata?
    Look for more information on XP/Vista interop in the coming weeks and months. In the interim, a beta version of Windows Desktop Search 3.0 has been released which includes some of the APIs required for metadata support.

    What other applications support XMP?
    People want to know what other applications support XMP metadata. Here is a short list (all of these are available on XP today):

    Why don’t my tags get written back to my photos?
    If you missed it from the previous post, scroll down to the ‘your mileage may vary’ section, where we cover this topic. The most common causes are read-only files, or other permissions issues. The bottom line is – if you can’t write to the file, neither can the Photo Gallery.

    - Scott Dart (program manager)

  • Windows Live Photo & Video Blog

    Windows Vista Photo Gallery Scoping

    • 1 Comments

    The Windows Vista Photo Gallery is built on top of a database that allows you to perform powerful queries against your collection of photos and video. Although a file will live in one only folder, you’ll be able to find it in new ways, like by the date it was taken, the date it was imported, the tags you have applied to it, the rating you have given it, or by searching for text in the file name, path, or caption.

    Indexing every file on your PC would be very time consuming and resource intensive, and is not usually required since most people keep their photos in one or two specific places on their PC. The most common locations are added to ‘scope’ by default (and therefore get indexed automatically).

    • \Users\<user>\Pictures
    • \Users\<user>\Videos
    • \Users\Public\Public Pictures\
    • \Users\Public\Public Videos\

    The public folders are great for families that share a PC and have a shared set of photos that they want everyone to see. Any photos stored in the Public folders will be able to be seen by all of the other users on the PC. Any tags that get added to these photos will show up in the Gallery for the other users of the PC automatically.

    If you keep your photos in a different location (like an external hard drive), it’s easy to add your photos to the Gallery. Select ‘Add Folder to Gallery…’ from the ‘File’ menu. This will let you browse for the folder on your PC (maybe it’s on an external hard drive, or even a network location).

    Once you have added the folder, the Gallery will start indexing this new location for you. The Photo Gallery will automatically stay in sync with any changes that are made in any of the folders that are in scope.

    - Scott Dart (Program Manager)

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