Considering Durations and Replays to Improve Music Recommender Systems
The consumption of music has its specificities in comparison with other media, especially in relation to listening durations and replays. Music recommendation can take these properties into account in order to predict the behaviours of the users. Their impact is investigated in this paper. A large database was thus created using logs collected on a streaming platform, notably collecting the listening times. The proposed study shows that a high proportion of the listening events implies a skip action, which may indicate that the user did not appreciate the track listened. Implicit like and dislike can be deduced from this information of durations and replays and can be taken into account for music recommendation and for the evaluation of music recommendation engines. A quantitative study as usually found in the literature confirms that neighborhood-based systems considering binary data give the best results in terms of MAP@k. However, a more qualitative evaluation of the recommended tracks shows that many tracks recommended, usually evaluated in a positive way, lead to skips or thus are actually not appreciated. We propose the consideration of implicit like/dislike as recommendation engine inputs. Evaluations show that neighbourhood-based engines remain the most precise, but filtering inputs according to durations and/or replays have a significant positive impact on the objective of the recommendation engine. The recommendation process can thus be improved by taking account of listening durations and replays. We also study the possibility of post-filtering a list of recommended tracks so as to limit the number of tracks that will be unpleasantly listened (skip and implicit dislike) and to increase the proportion of tracks appreciated (implicit like). Several simple algorithms show that this post-filtering operation leads to an improvement of the quality of the music recommendations.