What is a Mean Opinion Score or MOS?
Tags: mos, videoquality
Published: 2019-09-16 16:03:54

---
title: What is a Mean Opinion Score or MOS?
published: true
tags: MOS,Video Quality
canonical_url: https://www.headspin.io/blog/what-is-mean-opinion-score
---


Mean opinion score (MOS) is a measurement of the quality of experience, commonly used in profiling the quality of audio and video content. HeadSpin’s AI engine continuously measures video mean opinion score of mobile application video during a performance session test. The following is a screenshot of Video Quality MOS on HeadSpin’s waterfall UI timeline highlighted with a red outline.

**MOS Performance Metric in HeadSpin’s waterfall UI  
 ![mos_performance_metric_in_HeadSpins Waterfall UI](https://www.headspin.io/hs-fs/hubfs/_website%20files/Images/mos_performance_metric_in_HeadSpins%20Waterfall%20UI.png?width=1600&name=mos_performance_metric_in_HeadSpins%20Waterfall%20UI.png)**

Performance Session Link:  
[https://ui-dev.headspin.io/sessions/de8d3768-c57d-11e9-bcde-f01898ea5299/waterfall](https://ui-dev.headspin.io/sessions/de8d3768-c57d-11e9-bcde-f01898ea5299/waterfall)

Video contents are incorporated in different types of mobile applications: live streaming sports and events, live streaming news, explanation video, cutscene in a game, introduction/walkthrough video, live communication video, video as a file etc. Poor video experience can negatively impact user’s overall experience. It is crucial for mobile developers and QA teams to understand how well their video performs on real devices in real network conditions.

## **HeadSpin’s AI Engine MOS**

HeadSpin’s mean opinion score ranges from 0 to 4, with 0 being very poor and 4 being excellent as shown in the following list.

Score range:

- 0 very poor
- 1 poor
- 2 fair
- 3 good
- 4 excellent

**iPhone X Video Examples  
MOS: 3.54 [Youtube video]**    
  
 ![iphone-x-video-youtube-video-text-mos](https://www.headspin.io/hs-fs/hubfs/_website%20files/Images/iphone-x-video-youtube-video-text-mos.png?width=512&name=iphone-x-video-youtube-video-text-mos.png)

Comments: Although the content of the Chinese character and QR character are not crystal clear, no visible blockiness can be observed.

**MOS: 2 [NBA Video with blur and blockiness]**  
 ![MOS- 2 [NBA Video with blur and blockiness] ](https://www.headspin.io/hs-fs/hubfs/_website%20files/Images/MOS-%202%20%5BNBA%20Video%20with%20blur%20and%20blockiness%5D%20.png?width=682&name=MOS-%202%20%5BNBA%20Video%20with%20blur%20and%20blockiness%5D%20.png)

Comments: Notice that the player on the video screen capture is blocky. The scoreboard on the video is blurry.

**MOS Score: 0.57 [Youtube Video with severe blockiness]**![MOS Score- 0.57 [Youtube Video with severe blockiness] ](https://www.headspin.io/hs-fs/hubfs/_website%20files/Images/MOS%20Score-%200.57%20%5BYoutube%20Video%20with%20severe%20blockiness%5D%20.png?width=512&name=MOS%20Score-%200.57%20%5BYoutube%20Video%20with%20severe%20blockiness%5D%20.png)

Comments: Notice that the video is very blocky where the face of the person is indistinguishable.

## **Improve your video and delight your customers**

With real networks on real devices, many factors can affect the delivery of video content through mobile applications. The following list includes some of these different factors:

- The device and OS of the mobile application
- Bandwidth, latency, jitter packet losses of the network
- Misconfiguration of the content delivery network (CDN)
- Mobile application client issue playing the video
- Corrupted video download  
  

Using HeadSpin’s platform video mean opinion score (MOS) and network performance capture, developers and QA teams can resolve issues and improve mobile video viewing experience, which ultimately leads to delighted customers.

 ![](https://track.hubspot.com/__ptq.gif?a=3219205&k=14&r=https%3A%2F%2Fwww.headspin.io%2Fblog%2Fwhat-is-mean-opinion-score&bu=https%253A%252F%252Fwww.headspin.io%252Fblog&bvt=rss)

HeadSpin enables you to test your mobile app on real devices and real networks around the world for real-world user experience conditions right from your web browser. No code changes needed. [Start your Free Trial](https://ui.headspin.io/register?referral=start-testing-promo)