Re-Evaluating PSNR Global Weighting Schemes for Quality Assessment in Professional Multigeneration Video Coding Workflows

The transition to IP-based broadcasting and the adoption of UHD resolutions (4K/8K) have made bandwidth optimization a critical challenge in professional video contribution networks. In these environments, successive encoding stages require high-fidelity formats, predominantly 4:2:2, to prevent cumulative degradation. However, legacy objective quality metrics, such as the ITU-recommended 6:1:1 PSNRGlobal scheme and perceptual color-sensitivity models, apply fixed mathematical coefficients that ignore the physical sample topology of the video signal. Consequently, these static models structurally penalize 4:2:2 workflows by mathematically undervaluing their chrominance payload. To overcome this limitation, this paper proposes a mathematical subsampling-based scheme that dynamically aligns component weights with the actual physical sample density of each chroma profile. To validate this topology-aware framework, ten diverse 4K sequences were evaluated across a three-generation 10-bit HEVC pipeline. Encodings used Main 4:2:2 10 and Main 10 profiles across contribution (20–90 Mbps) and distribution (8–32 Mbps) stages. Evaluated using strictly bounded Bjøntegaard Delta (BD) metrics, results demonstrate that while legacy metrics inaccurately suggest 4:2:0 superiority, the proposed framework reliably captures the advantages of 4:2:2 in 96% of BD-PSNR (>0) and 94% of BD-Rate (<0) cases, yielding indicative average savings of 27.32% in bitrate and +0.53 dB in quality. These findings challenge current industry assessment standards, providing a corrected methodological baseline for optimizing bandwidth allocation in broadcast contribution networks.