Metrics

So there I was, having dinner on a Saturday night date night with my wife… And in comes a text: “Hi Jan, I was wondering when you compute SSIM, do you use a single channel or multi-channel? And if multi-channel, then anything different than averaging the three?” (And yes, anyone with children, even grown children, checks incoming texts on a …

We’ve updated several lessons in our Video Quality Metrics course, including some relating to the Moscow State University Video Quality Measurement Tool.  The Moscow State University (MSU) Video Quality Measurement Tool (VQMT) is a tool that I use almost every day to analyze and compare encoded files. Our course, Computing and Using Video Quality Metrics: A Course for Encoding Professionals, …

Here are the free “must-have” apps I install on every Windows computer (and three for-fee tools for deeper analysis).  I just received a new Dell Precision 7820 server and had to prepare it for video transcoding and analysis. Here are the tools I installed to get up and running. I present the list and links first and then a list …

New lessons detail how to use FFMetrics; updated lessons on what VMAF is, how to compute VMAF with FFmpeg, and how to interpret VMAF scores. Just a quick note to let you know about new additions and updates to our course, Computing and Using Video Quality Metrics: A Course for Encoding Professionals, which teaches encoding professionals how to choose and …

As of June 22, 2022, libaom-AV1 and SVT-AV1 tune for PSNR by default, and libaom-AV1 doesn’t appear to have a mode that optimizes actual video quality. Be sure to verify and consider this when comparing the codecs to others. Most of the time with codec experimentation, a lapse in attention costs you hours, days, or weeks of re-encoding and re-testing, …

The top rung of your encoding ladder is the most expensive to deliver, and in many regions, it’s also the most frequently viewed. Encode at too high a bit rate and you’re wasting money; encode too low, and you’re potentially reducing viewer quality of experience. This makes choosing the top rung bitrate a key task for all streaming producers. This …

Moscow State University’s Video Quality Measurement Tool (MSU VQMT) is my go-to utility for computing and visualizing objective metrics like VMAF, PSNR, and SSIM. In version 13, MSU increased codec compatibility and metric performance, added new HDR metrics and display capabilities, and enhanced VQMT’s already best-in-class visualization tools. If you’re a VQMT user, it’s an essential upgrade. If you’re not, …

Just a brief announcement that I’ve updated the course, Computing and Using Video Quality Metrics: A Course for Encoding Professionals, that teaches encoding professionals how to measure and apply metrics like VMAF, SSIMPLUS, MS SSIM, SSIM, and Apple’s AVQT. The updates include: Lessons on computing and applying Apple’s AVQT metric. A lesson on computing the weighted average bandwidth and quality …

This article is derived from a lesson in Streaming Media 101: Technical Onboarding for Streaming Media Professionals. If you’re looking for an efficient way to get up to speed on key streaming terms, technologies, workflows, and best practices, check out the course here.  Companies distribute videos for a myriad of reasons; sometimes as the product, sometimes to sell or market …

Author’s note: After completing this long and arduous post, Apple sent a note that I was interpolating their scores incorrectly, leading to more analysis shown as an addendum below.  What: This article compares Apple’s AVQT metric to VMAF and SSIMWAVE’s SSIMPLUS metrics, with very limited subjective testing from Subjectify.us. The testing was extremely limited as are the conclusions you should …