This paper presents a new video database (BVI-HFR), which contains content with a variety of frame rates from 15Hz to 120Hz, that can be used to demonstrate the benefits and limitations of higher frame rates, as well as investigating the role that frame rates play from capture to delivery. A characterization of the video database using low-level descriptors is also provided, which establishes that it successfully spans a variety of scene types and motions, and compares well to existing video databases. Subjective evaluations performed on the video database, have demonstrated a significant relationship between frame rates and perceived quality, up to 120Hz. They also confirm that the relationship between frame rate and perceived quality is content dependent.Index Terms-High frame rates, video database, subjective quality assessment.

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A frame rate dependent video quality metric based on temporal wavelet decomposition and spatiotemporal pooling.

Video frame rates, higher than those in conventional use today, have been shown to lead to an increase in perceived quality due to a reduction in the visibility of motion artifacts, specifically motion blur and temporal aliasing. Despite this, frame rates used in television and cinema have remained constant for many years. Although not currently in widespread use, the most recent UHDTV video standard (Rec. 2020) specifies higher spatial resolutions and a wider dynamic range than its predecessor; it also supports frame rates up to 120 Hz. In this context, we investigate here the influence of temporal sampling rate on the visibility of aliasing artifacts. Our results show that impairments in motion quality can be tolerated to a degree, and that it is acceptable to sample at frame rates 50% lower than the critical frame rate required to completely eliminate perceptible motion artifacts. Based on real world data related to median viewing distances and screen sizes, we make the recommendation that frame rates should be at least 100 Hz in future immersive video formats. Two further experiments show how the critical frame rate is dependent on both stimulus size and luminance. With respect to luminance dependence, our results indicate that the critical frame rate for a bright high-dynamic range display may be 30% higher than that for a conventional low-dynamic range display.

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In this paper we investigate the impact of frame rate variation on HEVC video compression, and demonstrate that high frame rates (60+ fps) can lead to increased perceptual quality, notably in high bitrate environments. In order to quantify content dependence, a novel way of partitioning video sequences into categories is proposed. Results show that rate-quality performance is improved at higher frame rates for video sequences with camera motion, whereas lower frame rates are favorable in sequences with complex motion (e.g. dynamic textures). We calculate that 60 fps and 120 fps are optimal choices of frame rate at bitrates of 3 Mbps and 7 Mbps respectively, demonstrating that increased frame rates are both feasible and desirable, given current broadcast data rates.

In this paper we present the BVI-SR video database, which contains 24 unique video sequences at a range of spatial resolutions up to UHD-1 (3840p). These sequences were used as the basis for a large-scale subjective experiment exploring the relationship between visual quality and spatial resolution when using three distinct spatial adaptation filters (including a CNN-based super-resolution method). The results demonstrate that while spatial resolution has a significant impact on mean opinion scores (MOS), no significant reduction in visual quality between UHD-1 and HD resolutions for the super-resolution method is reported. A selection of image quality metrics were benchmarked on the subjective evaluations, and analysis indicates that VIF offers the best performance.

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