Most existing datasets for sound event recognition (SER) are relatively small
and/or domain-specific, with the exception of AudioSet, based on a massive
amount of audio tracks from YouTube videos and encompassing over 500 classes of
everyday sounds. However, AudioSet is not an open dataset---its release
consists of pre-computed audio features (instead of waveforms), which limits
the adoption of some SER methods. Downloading the original audio tracks is also
problematic due to constituent YouTube videos gradually disappearing and usage
rights issues, which casts doubts over the suitability of this resource for
systems' benchmarking. To provide an alternative benchmark dataset and thus
foster SER research, we introduce FSD50K, an open dataset containing over 51k
audio clips totalling over 100h of audio manually labeled using 200 classes
drawn from the AudioSet Ontology. The audio clips are licensed under Creative
Commons licenses, making the dataset freely distributable (including
waveforms). We provide a detailed description of the FSD50K creation process,
tailored to the particularities of Freesound data, including challenges
encountered and solutions adopted. We include a comprehensive dataset
characterization along with discussion of limitations and key factors to allow
its audio-informed usage. Finally, we conduct sound event classification
experiments to provide baseline systems as well as insight on the main factors
to consider when splitting Freesound audio data for SER. Our goal is to develop
a dataset to be widely adopted by the community as a new open benchmark for SER
research