  High Dynamic Range (HDR) videos are able to represent wider ranges of
contrasts and colors than Standard Dynamic Range (SDR) videos, giving more
vivid experiences. Due to this, HDR videos are expected to grow into the
dominant video modality of the future. However, HDR videos are incompatible
with existing SDR displays, which form the majority of affordable consumer
displays on the market. Because of this, HDR videos must be processed by
tone-mapping them to reduced bit-depths to service a broad swath of SDR-limited
video consumers. Here, we analyze the impact of tone-mapping operators on the
visual quality of streaming HDR videos. To this end, we built the first
large-scale subjectively annotated open-source database of compressed
tone-mapped HDR videos, containing 15,000 tone-mapped sequences derived from 40
unique HDR source contents. The videos in the database were labeled with more
than 750,000 subjective quality annotations, collected from more than 1,600
unique human observers. We demonstrate the usefulness of the new subjective
database by benchmarking objective models of visual quality on it. We envision
that the new LIVE Tone-Mapped HDR (LIVE-TMHDR) database will enable significant
progress on HDR video tone mapping and quality assessment in the future. To
this end, we make the database freely available to the community at
https://live.ece.utexas.edu/research/LIVE_TMHDR/index.html
