14 DAY TRIAL // There is an array of technical details behind the content built for Windows DreamScene in Windows Vista. With the latest operating system from Microsoft, users will be able to discard the static wallpapers for a superior experience delivered by animated backgrounds. Windows Vista even enables users to employ their own videos as backgrounds for the operating system. But first, there are a few aspects that need to be considered. According to Alex Kipman, the Ultimate's Group Manager, users have to pay mind to content, rendering and encoding attributes.
As far as content is concerned, DreamScene backgrounds require a static camera angle, no zooming or panning. The content has to focus in the top quarter and bottom quarters to integrate with the glass surface in Windows Vista. The recommended time length is 30 seconds, the actual motion has to be subtle and to loop and the content has to seamlessly adapt to 16:9 and to 4:3.
"From a rendering perspective: render the content natively at 720p, have the content natively rendered at 16:9, but make sure it crops nicely at 4:3, cap the rendering at 30 fps (bonus points if you can make something interesting at 15 fps), make sure the first frame and the last frame of the video go together so you get a sense it keeps going forever and output the final results as raw and uncompressed AVI (or other uncompressed and raw format)," Kipman explained.
Last but not least comes encoding. While creating content for the Windows DreamScene use progressive pre-processing and do not let the de-interlacing up to the encoder. Also, you should use Xscaler to perform scalings. Bitrate is a core variable because it will determine the balance between CPU consumption, size and quality. You also have to take into account the fact that DreamScene supports only MPG or WMV formats.
Here are some additional details provided by Alex Kipman:
WMV: - 5 Mbps WMV - Select video stream WM video Stream 1 - Width: 1280 - Height: 720 - Aspect Ratio: 16:9, Pixel [1:1] - Encoder: Windows Media Video 9 - Framerate: 29.97 - Bitrate: 4991 - Bitrate type: CBR - Number of passes: 1 - Seconds / Keyframe: 1 - Image quality: 97 I- nterlacing: Non-Interlaced - Buffer: 5000 - Video Codec: Complex Auto - No Audio
MPG: - 15 & 8 Mbps MPEG2 - Stream Format: Generic ISO MPEG Stream - Stream Type: MPEG-2 Elementary Stream - Width: 1280 - Height: 720 - Frame rate: 29.976 - Interlacing: Non-Interlaced - Aspect Ratio Code: 16:9 - Quality/Speed: Mastering Quality - Bitrate type: CBR - Video Bitrate: 15000 (8000) - Profile/Level: HP@HL - VBV Buffer Size: 1492 - Max GOP Size: 15 - Closed GOP: yes - Chroma Format: 4:2:0 - Intra DC Precision: 9 - Strict GOP bitrate: No - No audio used - Insert one sequence header before each GOP