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Standard DVD Authoring and Recording SDK
Slide Show Title Support
Slide show is a continuous presentation of a sequence of still images, with or without background music. The duration of each image is controlled by the assigned duration time. The duration for each image may vary, depending on the user's assignments. The background music can be continued from one image to the following ones without interruption, or the background music can be dedicated within the duration of the current image. The background music settings are depending on the user's choice.
Each slide image is formed a 'chapter' in the sequence. During the slide show presentation, viewer is able to browse images by activating the 'Next' or 'Prev' key on the remote controller.
The authoring SDK has the built-in encoder for full GOP (Group of Pictures) compression. Unlike common authoring program that only compresses the image to MPEG 'I' frame, this encoder is able to compress the image into a full MPEG GOP, including P/B frames. It enhances the color quality in the final screen image.
Each title in the DVD volume is able to house up to 99 slide images. When user has more than 99 slide images, additional titles can be compiled during the authoring stage to include the rest images and background audio files. However, owing to the DVD Spec limitation, an entire DVD volume only supports up to 999 chapters among all titles. Therefore, the maximum limitation on the slide image count is 999.
Encoding Process Overview
The built-in encoder routine in the authoring library for compressing slide images follows the standard algorithm stated in ISO13818 Spec. The color components of pixels of the source image are converted into YCbCr color space before forming 2D DCT coefficients. A default quantization table is applied during intra coding. An I frame, therefore, is formed within the final step of integrating a bit stream using variable length coding method (VLC). The P/B frames in the same GOP are to be formed in the same way but without motion compensation.
A dedicated ‘class’ has been developed to include all the functions to serve the needs for image encoding in the authoring library. When running the compilation, the authoring library creates objects of the encoding class and calls different functions in the object to output the result during each process step.
Illustrations
(Slide
Title)
(chapter 1)
-----
(chapter
n)
(Slide
Title with background music)
(chapter 1)
-----
(chapter
n)