Category Archives: Videos

YouTube TV app degrades 1080/60p videos to 720/60p for older TVs-and what to do about it

I recently uploaded a 4K/60p 3D video to Youtube. Unfortunately, when I played it on my TV using the Youtube app on the Roku box, it displays as 1280×720/60p. Why did Youtube degrade to 720p? We answer that question below.

A 1280 x 720 3D stream becomes two 640×720 clips – one for the left eye and one for the right eye which looks fuzzy. At 1920 x 1080, a 3D side by side format video retains 960 x 1080 for each eye, which is much greater resolution.

Bottom line3D videos should primarily be uploaded as 30p videos, even if originally shot in 60p if they are intended for viewing on Youtube television apps.

What happened?

My TV, like most vintage TVs that support 3D, does not support 60 frames per second except in 720p mode.

In fact, all 60p videos on Youtube are downgraded to 720p when playing on the Roku Youtube app.

The same video, when uploaded at 30p displays correctly as 1920×1080/30p and is not downgraded.

What this means

If you are a weirdo like me and shooting 3D video, do not upload any 3D video in 60p because it will be downgraded by TV-based viewing apps not to 1080/30p but to 720/60p. This is because TV’s that support 3D are, almost exclusively, from the 3D hey day era of about 2011 to 2013, after which manufacturers began to discontinue their 3D TVs. TVs of that age only supported 30p and did not support 60.

Youtube had a choice to degrade the video from 60p to 30p, or to retain 60 frames per second – they chose the later and degraded the resolution to 1280 x 720/60p, unfortunately.

If you intend for your 3D video to be viewed on 3D TVs, you will want to upload videos as 30p, even if you originally shot them in a 60p format.

Videos uploaded in 60p will play correctly TVs that support 60p and on most 3D computer monitors. If your target is a 3D TV, you will want to upload only a 30p version. But if your target is 3D computer monitors, you can upload 60p clips.


VR 3D, VR 180 stereoscopic cameras shown at #CES2018

I will do a post at some point on re-formatting conventional 3D video for use in VR Cardboard viewers.

Conventional 3D video typically used side-by-side or top over bottom encoding of 3D content.  Top over bottom does not work at all for conventional VR viewing apps, and side-by-side displays a horizontally squished/vertically stretched image perspective. Consequently, neither works with standard VR viewers. Side by side is also sometimes called “half side by side”.

Some apps do correctly recreate a side by side image but do so only in a small portion of the phone’s screen centered in front of the cardboard viewer’s lenses. Unfortunately, this small image cuts the image resolution so low that the image quality suffers tremendously and the original 3D content is nearly useless.

IF Cardboard viewing apps provided reformatting of standard 3D formats into VR 3D formats properly, this would not be a problem. But for now, it is a big problem.

A possible solution, based on my tests, is to take one’s original stereoscopic 3D and recompress an output file as full size, side by side. Upload the full size, side by side video to Youtube.

When played back on the Youtube viewer, these videos display using most of the phone screen, such that image resolution remains very good. Each eye sees an original image in a 960×540 resolution (roughly) which is far better than perhaps half of that seen on conventional side by side Cardboard viewing apps.

More on this another time.

 

“This video is 2D and 3D Simultaneously: the Pulfrich Effect”

Tom Scott has created a brilliant demonstration video of the Pulfrich Effect. You’ll need a pair of ordinary dark glasses – use just one side to cover just the right eye. Then watch his video. You’ll see the video in full color 3D, event though it is a 2D video.

3D video enthusiasts may already know a bit about how this works. When a camera is panning across a scene, each frame records a “position” in time. We sometimes use this trick to convert a 2D video into a 3D video by recording in 2D, but then creating a separate left and right track with the tracks separated by a single frame from the original 2D recording. This creates a left image track – and a right image track – by taking advantage of the movement in the scene.

The technique works as long as either the camera is moving or one or more objects in the scene are moving laterally. It does not work if objects are moving vertically or if objects or the scene are stationary.

The Pulfrich Effect uses the same idea but incorporates the peculiar nature of our optic system. Specifically, our eyes process darkened images slightly slower than bright images. The darkened image seen through dark glasses covering one eye are processed with a delay of about 15 milliseconds which works out to about 1/60th of a second. (The actual processing delay depends on the actual darkness of the image and could be more or less.)

Tom’s Youtube channel is here. He’s always got fascinating topics and I encourage you to subscribe to his channel on Youtube.

Experiment: I suspect this works also for VR 3D. Take a VR 360 video but keep the camera slowly rotating during filming. Then, cover one eye with a dark glasses shade while watching the VR video using a VR set up. As long as the subject is slowly moving laterally, the 3D effect should be visible in 3D!

[The featured photo for this post is from Pixabay.]

 

 

Majority of Americans may not be able to use VR headsets

Most (nearly all?) virtual reality viewers available online can not be used by those who need to wear eyeglasses, which is a majority of Americans.

The Problem

  • VR viewers lack space on the face side to accommodate the wearing of eye glasses.
  • VR viewers lack diopter adjustments.
  • VR viewers lack inter pupil distance (IPD) adjustments.

Who Does This Impact?

75% of Americans use some form of corrective eye lenses, split as 64% wear glasses and 11% wear contact lenses (Source: Corrective Lenses Statistics – Statistic Brain).

Nearly 100% of those over the age of 45 require reading glasses for close in viewing – or using most any virtual reality viewer. Almost all viewers lack sufficient space to wear reading glasses when the viewer is on the face. Attempting to wear reading glasses with a VR viewer is extremely uncomfortable as the viewer pushes the glasses into their face.

Unlike camera viewfinders that include a diopter adjustment, VR viewers are almost all fixed focal lengths or have limited adjustments (possibly only for myopia but not presbyopia).

Most VR viewers (but not all) have a fixed inter pupil distance (the distance between the eyes is fixed even though people have different distances – think of how binoculars work to address that!).

Consequently, VR viewing is – for a majority of Americans – either impossible or painful.

A few of the higher end viewers have – during the past year – begun to address this problem either by enabling the wearing of glasses while using the viewer, or by adding a focus adjustment.

The focus adjustment, however, is not sufficient. Of the 75% who need vision correction, some have significantly different corrections between the left and right eye. All VR focus adjustments make the same adjustment for both eyes – meaning such individuals can only get a good focus in one eye.

Again, think of binoculars. Binoculars solved this problem decades ago by having a master focus ring that adjust both eye views simultaneously, plus a single diopter adjustment for one eye. The inter pupil distance is adjusted in binoculars by positioning each lens further apart. Through these adjustments, binoculars long ago provided solutions to the majority that need vision correction.

A reasonable guess is that the VR industry views its customers as young gamers and hired young people with excellent vision to design their products, but who are oblivious to real world customers.

If the VR industry does not address these design defects urgently, the future of VR is itself in doubt.

When a majority of potential customers are likely to have unsatisfactory experiences, they will not purchase VR products and content. They will not post positive comments in reviews and online forums.

Media pundits said 3D failed because people had to wear “3D goggles” (their term for 3D glasses). In reality, the problem was a lack of compelling 3D content for consumers to watch at home.

VR, which really does use “3D Goggles” (and helmets too), is headed down the same path to oblivion if it does not deliver VR viewers that can be worn and used by a majority of the population.