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Published Date: 15 March 2023

What is VMAF?

VMAF, short for Video Multimethod Assessment Fusion, is a full-reference video quality metric introduced by Netflix alongside the University of Southern California.

The primary responsibility of VMAF is to predict video quality based on a reference and distorted video sequence. Netflix and other major platforms use this key metric to compare different video codecs, encoding configurations, encoders, and so on.

Key Components of VMAF

  • Visual Information Fidelity (VIF): Used for factoring in information fidelity loss on four spatial scales.
  • Detail Loss Metric (DLM): Used for measuring quality degradation, loss of details, and noticeable impairment in video streams.
  • Mean Co-Located Pixel Difference (MCPD): Used for measuring the temporal difference between the frames on luminance components.

Real-Time Performance

  • Regarding prediction precision, VMAF has been shown to outperform other primary image and video quality metrics, including SSIM, PSNR-HVS, and VQM-VFD based on performance on three to four data sets.
  • As per a 2017 set, engineers from RealNetworks determined that VMAF has good reproducibility as per Netflix’s performance findings.
  • As per the MSU Video Quality Metrics benchmark test, VMAF outperformed all the other metrics (including NEG), which were tested based on all compression standards (H.265, VP9, AV1, VVC).
  • There are ways to improve VMAF scores artificially without improving the perceived video quality by applying various functions before distorting the video.

Benefits of Using VMAF

  • VMAF outperforms other metrics, including the likes of PSNR and SSIM, based on accuracy and complexity.
  • VMAF uses several traditional metrics that measure perceived video quality in a data-driven manner to show practical and more accurate results.
  • VMAF is an open-source package, easily accessible and widely available.
  • VMAF has reliable support, uses a high-quality codebase, and has functional tools and libraries for enhanced results.

Related Terms

Video Quality

In simple terms, video quality is the characteristic of a video that determines how clear, crisp, and detailed the video transmitted to the viewer is.

Video Watermark

A video watermark is a digital copyright tool used to identify the video's copyright owner or prevent illegal distribution.

Video Editing

The process of manipulating and rearranging video footage after shooting to create the final product is called video editing.

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