Subject: Re: Menu Structure
Newsgroups: gmane.comp.multimedia.matroska.devel
Date: 2003-03-13 05:57:49 GMT (6 years, 16 weeks, 3 days, 3 hours and 18 minutes ago)
Here are some ideas I've had about how to mirror the DVD menu system, but first a description of how they work on a DVD. A menu on a DVD is composed of 4 parts. Video track Audio track Subtitle track IFO file The video track is the background to the menu. The audio track is what you hear when the menu is up. The subtitle track doesn't contain subtitles, instead it contains a single picture for the menu. Buttons that are displayed on the video track have there alternate, "highlighted version" on this picture. A small portion of the picture is selected and overlayed over the video to form the highlighted button. The IFO file contains several things, all in text. First it tells what file, streams, and stream segments to use for a menu. Next, it lists the coordinates of the "highlighted buttons" on the overlay mask contained in the menus subtitle track. Finally, it contains all of the instructions. Like pressing Left from this button highlights which other button. Or selecting this button plays the movie starting at this timecode, or takes you to this menu. ****************************** Now, how do we fit this into the Matroska? The first two are easy, you just have video and audio track encoded to your codecs of choice. The third would require a subtitle track. You could store the picture as a bitmap, but a PNG would take up much less space. It might be useful to define a subtitle codec-id for just putting a PNG in a block at whatever timecode. The fourth part is where it gets a little tricky. The hardest part would be changing all of the settings for VOBID and CELLID to instead tell the segment, tracks, and chapters of the Matroska file containing the necessary streams. Next, any video that was resized from the original would need the coordinates changed for where the buttons are located on the subtitle track. Other than that, everything could be left the same, or custom changed for anyone that was doing a custom project. Pamel http://www.matroska.org