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I am looking for any tools that can measure the video quality in a subjective way (As how the eye sees a moving picture). Are there any tools to which I could input a video file and get a subjective reading of how the quality of the video is?

Here is information thanks to snow about how to measure video quality

Note that the script there does not work and the other alternative is a windows app.

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superuser.com/questions/338725/… – Raja Dec 25 '12 at 17:01
    
@snow - Thanks, but the only tool there was for windows. I also happen to read the exact same thing as the answer there but it was somewhere else, don't really remember where. Good information. I will add that to the question. – Luis Alvarado Dec 25 '12 at 17:41
up vote 4 down vote accepted

There are two established algorithms that can measure the faithfulness of video to its source. You have to input two video streams, the original source and the encoded version, and the algorithm calculates the faithfulness and outputs a figure.

Unfortunately for you, they both require you to supply the un-compressed source along with the compressed video, to do a comparison. There is no reliable algorithm to detect video quality that doesn't require the source.

  • PSNR is a very simple measure that just takes the difference in each pixel between the source and encoded version and averages out the squares of this difference across all pixels in all frames equally, arriving at a figure, which can be expressed as a "signal to noise ratio".

    As video codecs became increasingly tuned psycho-visually, this algorithm became more and more irrelevant. Today, optimising a video codec for PSNR equates to optimising it to look badly. It is a very bad measure of how faithful to the source video actually looks to human eyes.

  • SSIM was created in large part due to these deficiencies in PSNR. It is a more complex algorithm that also takes into account how well the shape of structures in the resulting image correspond to structures in the source. This heavily biases against certain artefacts common in earlier block based compression (eg MPEG-2 as used in DVD) which includes blocking or ringing, artefacts that contribute a lot to our perception of the video quality even though their contribution to PSNR is lesser.

    SSIM arrives at a figure indicating similarity, which can be converted to a ratio similar to PSNR.

    As video codecs have evolved even further, SSIM now too has limitations, making it similarly unsuitable as a catch-all measure of video faithfulness. Modern video codecs such as h.264 do not have as much of a problem with blocking structures due to features such as in-loop deblocking and 4x4 transforms, whereas they do still suffer from loss of detail and noise (blurring), which is not well measured by SSIM.

There are other algorithms in existence, some of which claim to solve the deficiencies in these algorithms, but none of which have gained as much popularity.

Therefore, neither of these algorithms is a suitable way of measuring perceptual video quality. Instead, tuning video codecs requires a lot of observation: preferably, double-blind comparisons so that the observer can't be biased by knowing the codec in use: a feat that is difficult for video codecs which leave tell-tale signs unique to the codec even in fairly high bitrate compressed videos.

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Thank you for the PSNR / SSIM explanation. – Luis Alvarado Feb 4 '15 at 12:46

Here is a Streaming Video Quality tool I accidentally found. Unfortunately I can't recall the toggle method. I have been trying to re-find it. Here are my recent efforts that include an explanation of the tool:

Please tell me the name of the feature and especially how to enable / disable it. I found the toggle by accident, and it was cool, but then I left it toggled on and now can't remember how to turn it off. It is an awesome feature though.

First noticed in Version 47.0.2526.80 m; still displayed after upgrade to Version 47.0.2526.106 m.

A picture is best, so that's first (green bars and stats at top of screen): VidStatOverlay0 VidStatOverlay1

Here's the text description of the behavior: When you you click on a video to play it, in the streaming playback window there is a feature to turn on an overlay (of the same type as the play / pause button and video progress bar at the bottom of the screen) at the top of the screen that shows informative stats like State (play or pause), load in ms, manifest in ms, stalls, buffer rate in s/s, buffer left in s (when clicking in the video these get covered up by the usual OneDrive menu items of share | add to album | download | delete | embed | edit tags | etc). There are also two more lines below these, one for Audio and one for video. Each of these lines has a quality rating (0, 1, 2, etc) and a graphic of dots added in a line. The length of the line represents the length of the video load. the dots are color coded to show 'waiting for response,' 'receiving bytes,' downloaded, appending, appended, and error. The audio line also shows stats for avg wait in ms and avg receive in ms. The video line shows additional stats for avg wait in ms, avg receive in ms and avg bandwidth in mbps. The is a vertical line that progresses across the dot plot and this line represent the playback position of the video relative to the cached data.

Key words: State (play or pause), load in ms, manifest in ms, stalls, buffer rate in s/s, buffer left in s, 'waiting for response,' 'receiving bytes,' downloaded, appending, appended, and error avg wait in ms and avg receive in ms bandwidth in mbps

This is similar in nature to the post Chrome's video statistics feature Categories:47-StableDiscuss ChromeWindows 8 https: / / productforums.google.com/forum/#!msg/chrome/x7q1rM2G3DY/wYpD4896yRwJ;context-place=forum/chrome


12/17/15 Google says: I'm not familiar with this feature at all, but my initial guess would be that it's some sort of extension. I don't recognize this as a Chrome feature.

My Reply to them was: I turned off all extensions and this still exists. I also know I did not install any extensions or even any other SW at all for weeks (other than anti-virus updates) prior to finding this 'feature.

I will note that I found the feature while using Chrome to play a OneDrive video in OneDrive's native streaming player. I went up one side and down the other in two separate hour-long chats with OneDrive 'experts' (clearly Tier I and limited to a problem solving tree) and at the end, microsoft, in their wisdom, says they think it's a virus. Seriously? That's where I gave up on them and went to the experts at Google.

I wish I could remember if I found it with a right-click pop-up, a hidden context menu item, or one of those lucky accidental finds of a shortcut key. So it could be related OneDrive. Unfortunately, on the day I found and used the toggle function I only tried it in Chrome, not another browser. And now I can't remember the toggle function.

It's a very sleek and informative function on streaming video. I would think either Google or microsoft would want to take credit for it.

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Your interpretation of quality and my interpretation may differ as well as anyone else, therefore your subjective way is tainted. You need a definitive measurement of sort that will recognize pixel strength, movement, blur, saturation, density, focus and such.

This will all be handled according to the equipment used of course. What type of input/output media-processing-recording and capture are being used. As well as storing the data via film, digital or magnetic tape?

The variables are consistence to the finished product. ie: $100,000 3D theater projector or a home movie 8mm camera? There is a difference.

Now, back to your graphics card. Can it handle stressing the media analysis?

My point is this. There is no ONE GOOD ANSWER. I would suggest starting to research from this site : http://www.linux.com/news/software/applications/321373-the-beat-goes-on-open-source-multimedia-tools-part-2

This may not be definitive enough but you can get a good start.

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Good answer "Turbo" (I know the real you muhahaha). – Luis Alvarado Dec 25 '12 at 22:41
    
You just scratched the surface, mister. It goes much deeper. Hoorah! – Ringtail Dec 26 '12 at 0:50

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