Image Quality

Question: What are the differences between Indeo® video interactive and Indeo® video Release 3.2?

The main differences are higher quality video, processor scalability, and new features designed for interactive multimedia applications. Indeo® video interactive software uses a completely new compression algorithm, including advantageous features such as bidirectional prediction, to yield better image quality than Release 3.2, comparable to software MPEG. Indeo video interactive also encodes data at lower rates than Release 3.2, so more video of a given quality can fit onto a CD­ROM. Indeo video interactive also allows image quality to scale according to the processor power available. Finally, Indeo video interactive supports the development of interactive multimedia applications with features unavailable in Release 3.2. You can specify that portions of a video frame be rendered as transparent, or that only a portion of the frame be decoded. Users can change the brightness, contrast, and saturation of video files during playback. Key frames can be placed wherever they are needed, at arbitrary intervals. And video files can be protected from unauthorized access.

Question: What is the benefit of aperiodic keyframe access?

Aperiodic keyframe access improves compression and image quality by allowing keyframes to be placed at scene changes or edit boundaries. It also improves user access, as you can place key frames at any point in the file to which you wish users to be able to jump.

Question: What's the difference between the Good, Better and Best compression settings, and how do they relate to scalability?

IndeoŽ video interactive has three selectable compression modes: good, better, and best. The setting is independent of scalability; it controls the compression algorithm. The best compression mode gives the best quality video but requires a more powerful processor for playback. Given adequate processor power and system resources, quality improves significantly from good to best compression settings.

Question: What is scalable quality and what does the scalability compression setting do?

Earlier versions of IndeoŽ video dropped frames when video decompression requirements surpassed the capacity of the system. Instead of dropping frames, Indeo video interactive can gradually reduce image quality as demands on the system exceed the available capacity. Reducing the image quality decreases the system resources required to play back the video without dropping frames completely. To enable this feature, turn the Scalability compression setting on in the compression dialog before compressing the video.

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