US Patent 8452778 Training of adapted classifiers for video categorization

A classifier training system trains adapted classifiers for classifying videos based at least in part on scores produced by application of text-based classifiers to textual metadata of the videos. Each classifier corresponds to a particular category, and when applied to a given video indicates whether the video represents the corresponding category. The classifier training system applies the text-based classifiers to textual metadata of the videos to obtain the scores, and also extracts features from content of the videos, combining the scores and the content features for a video into a set of hybrid features. The adapted classifiers are then trained on the hybrid features. The adaption of the text-based classifiers from the textual domain to the video domain allows the training of accurate video classifiers (the adapted classifiers) without requiring a large training set of authoritatively labeled videos.