Schematically Quality-Rate curve can be illustrated in the following graph:
It’s obvious that Quality-Rate curve depends on video content (e.g. significant motion), video resolution and your encoder’s settings.
However, it’s important to detect whether your encoder with a predefined bit-rate places your video in the Flat Region or not. You need find a Bitrate threshold, after it each addition to Bitrate causes a negligible improvement in Quality.
If you divide video streams in your DB into non-overlapping classes (e.g. HD resolution, slow motion, cartoons) and take a representative of each class. Then you encode each representative with different bitrates until you reach flatening zone. Thus, you determine the Bitrate Threshold for each class.
For a new video movie you specify manually or automatically its most probably class and pick the corresponding Bitrate Threshold. Consequently you know that no sense to encode this new movie with a bitrate exceeding the Threshold.
23+ years’ programming and theoretical experience in the computer science fields such as video compression, media streaming and artificial intelligence (co-author of several papers and patents).
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