# Personalized Video Summarization: A Comprehensive Survey of Methods and Datasets
## 4 Classification of Personalized Video Summarization Techniques
### Type of Personalized Summary  
Video summarization is a technique used to generate a concise overview of a video, which can consist of a sequence of still images (keyframes) or moving images (video skims) [52]. The personalized video summarization process involves creating a personalized summary of a specific video. The desired types of personalized summaries following this process also serve as a foundation for categorizing techniques used in personalized video summarization. Different possible outputs can be considered when approaching the problem of personalized summary, such as the following:  
* _Static storyboards_ are also called static summaries. Some personalized video summaries consist of a set of static images that extract highlights, and their representation is made into a photo album [15; 16; 21; 22; 23; 29; 33; 35; 43; 44; 48; 52; 53; 54; 55; 56; 57; 58; 59]. The generation of these summaries is performed by extracting the keyframes according to the user's preferences and the summary criteria. * _Dynamic summaries_ are also called dynamic video skims. Personalized video summarization is performed by selecting a subset of consecutive frames from all frames of the original video that includes the most relevant subshots that represent the original video according to the user's preferences as well as the summary criteria [12; 14; 17; 18; 19; 20; 25; 27; 28; 30; 31; 36; 38; 39; 45; 46; 48; 55; 60; 61; 62; 63; 64; 65; 66; 67; 68; 69; 70]. * A _Hierarchical summary_ is a multilevel and scalable summary. It consists of a few abstractive layers, where the lowest layer contains the largest number of keyframes and more details, while the highest layer contains the smallest number of keyframes. Hierarchical video summaries provide the user with a few levels of summary, which provides the advantage of making it easier for users to determine what is appropriate [49]. Based on the preferences of each user, the video summary presents an appropriate overview of their original video. [PERSON] and [PERSON] [8], to accurately identify the related concept with a frame, proposed a hierarchical mechanism to classify the images. The role of the system that performs the hierarchical classification is the deep categorization of a framework against a classification that is defined. [PERSON] and [PERSON] [13] suggested a summary algorithm, where server metadata descriptions, contextual information, user preferences, and user interface statements are used to create hierarchical summary video production. * _Multiview summaries_ are summaries created from videos recorded simultaneously by multiple cameras. When watching sports videos, these summaries are useful, as the video is recorded by many cameras. In the multiview summary, challenges can arise that are often due to the overlapping and redundancy of the contents, as well as the lighting conditions and visual fields from the different views. As a result, for static summary output, the basic frame can be extracted with difficulty, and for the video, to shoot border detection. Therefore, in this scenario, conventional techniques for video skimming and extracting keyframes from videos recorded by a camera cannot be applied directly [49]. In personalized video summarization, the multiview video summary is determined based on the preferences of each user and the summary criteria [18; 26; 39; 71]. * _Fast forward summaries:_ When a user watches a video that is not informative or interesting, they will often play it fast or move it forward quickly [72]. Therefore, in the personalized video summary, the user wants to fast forward the video segments that are not of interest. In [51], [PERSON] et al., in order to inform the context, users play in fast forward mode the less important parts. [PERSON] et al. [41] proposed an adaptive fast forward personalized video summarization framework that performs clip-level fast forwarding, choosing from discrete options the playback speeds, which include as a special case the cropping of content at a playback speed that is infinite.