Fitting Local Photo Files on 3D TV: LeTV and Vizio

This page is under construction
This page was last updated on: 1/29/2020

Last summer (2019) my brother-in-law, David Vail, told me of chance to obtain a 55" diagonal 2160h x 3840w resolution ("4K" pixels wide) LCD 3D TV: LeTV Super TV X3-55 Pro UHD Ultra-thin LED Smart TV (L553AN), surplussed from a line of discontinued TVs by Chinese company Le Shi Zhi Xin Electronic Technology (Tianjin) Limited. It was declared to not be HDCP 2.2 compliant. I followed up by purchasing the LeTV 3D TV for $375 (plus $340 shipping :-) ) from a company in San Diego.

Our family already had a Vizio 44" 1080h x 1920w 3D TV purchased in 20?? mainly to watch Direct TV, and also movies including 3D thru a connected Blu-Ray player (Xbox, then a Sony). Later I added a dedicated Windows 7 Lenovo PC with NVIDIA 1080h x 1920w video to watch internet streaming video. David, a long-time avid 3D photographer, built his own stereo dual-camera rigs. He would take 3D photos on family visits and on various vacation trips of his own, and then share many with us, typically as half-height AB (Above-Below, Over-Under, Top-Bottom) stereo pairs for display on the Vizio TV, either as files local to the TV via USB flash drive, or via the Lenovo PC. In both cases the Vizio internal support for displaying the half-height AB stereo pair photos was used to view the photos in 3D.

Side By Side (SBS) is a format commonly output by stereo cameras, directly or packaged in MPO format. The formats can be both accepted and output by Stereo Photo Maker (SPM), a stereo photo editor. Examples of SBS format are shown just below.

The half-AB (half-Above-Below) and half-SBS (half-Side-By-Side) formats shown  below are possible outputs of SPM.
The half-AB and half-SBS stereo formats are directly supported for JPEG stereo photo file images for both the 55" 3D LeTV and 42" 3D Vizio TV, which are passive screen TVs. These formats strip out every other horizontal line (half-AB) or vertical column (half-SBS) of each full-size image of a stereo pair and concatenate the resulting images to form a single full-size image, where "full size" means the full resolution of the TV screen.

[---> Note - these half-formats may have legacy history before passive technology that I missed. I remember experimenting with full-size photo pairs in 90's, page flipping on SGI workstation, and with frame interlace at 60Hz TVs and 120Hz monitor vertical over-scan rates, all  with shutter glasses. Maybe Nvidia?]
LeTV 55" 3D Supported Photo Formats:
Overall height: Exactly 2160 pixels
Overall width: Equal or less than 3840 pixels
Vizio 42" 3D Supported Photo Formats:
Overall Height: Exactly 1080 pixels
Overall width: Equal or less than 1920 pixels
Both the LeTv and the Vizio use passive circular polarized technology for display of horizontal-line interlaced 3D images. This means that the LCD display panel includes a "transparent" filter mask to circular-polarize the sequential horizontal pixel-lines of the display alternately clockwise and counter-clockwise from top to bottom (2160 lines for the LeTv, and 1080 lines for the Vizio). The polarizing scheme is compatible with RealD 3D movie glasses (which direct light to right or left eye based on polarization direction), and does not affect 2D viewing.

Because of the TVs' passive screen & 3D glasses hardware combination, they must present the stereo image to the screen in row-interlace format, with one image displayed on odd rows and the other on even rows. This means that, at most, only half of a full-screen's worth of each image of the stereo pair can be displayed in stereo form. Thus the half-AB and half-SBS forms are appropriate image inputs, reducing needed file size.

For both of the passive screen TVs mentioned, the JPEG pixel height of the half format is required to be the screen height, while the pixel width of the half-format must be equal to or less than the screen width for correct stereo display.

For the LeTV, the row-interlace format alternates Left for odd pixel rows, Right for even pixel rows, where rows are numbered from the screen Top, starting with "Row 1" and ending at screen bottom with "Row 2160". 
---> verified below for LeTV. Vizio issue?

---> [vizio vs LeTv - which polarizing direction at top line? ]

[add image showing polarization directions, with link to source]
This site has simple descriptions and illustrations of anaglyph, active shutter, and passive polarization (linear and circular) technologies:
Upon receiving the LeTv, I experimented with it by connecting up the Sony Blu-Ray player, Kindle Fire TV, and Lenovo PC via HDMI cables. DVDs, 2D and 3D Blu-Ray, and streaming TV worked fine with the LeTv. However after about a week, the Lenovo, with its NVIDIA display adapter, stopped recognizing the HDMI connection to the Letv. This was eventually determined to be due to the LeTv's HDCP 2.2 non-compliance and was rectified by installing a "ViewHD Ultra HD / 4K 1x2 Mini Powered Splitter / HDMI 1.4 (Model VHD-Pluto)" into the HDMI connection path. [cite Yahoo group source].

I also became more familiar with the free Windows Stereo Photo Maker (SPM) application, and how it could be used to convert my collection of half-height AB stereo photos from David into row-interlaced photos that could be stored locally (e.g. flash drive on USB port) at the LeTv instead of being served from the Lenovo PC. This led to the more general issue of conversion of any size stereo pair for local display on the Letv, and discovery of some sizing limitations for correct display of 3D images.

[add row-interlaced example]
LeTV description:

The LeTV is a "4K" 3840w x 2160h pixels 55" screen Passive 3D TV, compatible RealD 3D glasses.

TBD - point to specs

The LeTV can display 3D in row-interlace form photos in half-AB or half-SBS (each 3840w or less by exactly 2160h pixels) format that are displayed full screen, from an external source such as a computer thru the tv's hdmi inputs. However, the LeTV cannot display such photos (half-AB or half-SBS format) which are stored in its own local internal memory or attached USB storage.
Intro - why this page?
- the LeTV uses passive screen technology to display row-interlaced stereo images
- want to display stereo photo files from local storage rather from an external server such as a computer.
- supported stereo modes (half AB, half SBS) depend exclusively on external input
- The LeTV automatically scales, maintaining aspect ratio, locally stored JPG image files to fit within its 3840w x 2160h pixel viewing area.
- If formatted as row interlace, exactly 2160 pixels high, and less than or equal to 3840 pixels wide, such files can be viewed in 3D if prepared using stereo pair source images.
- The LeTV does not distinguish locally stored normal JPG images from those that are prepared for row-interlaced stereo: the stereo view is accomplished with the passive screen alternating circular polarity of adjacent rows of pixels combined with circular polarized (left & right lenses) 3D viewing glasses.

Local storage (internal, USB)
- JPG row interlace stereo files are workaround
- not recognized as stereo by by LeTV, but display OK
- displayed JPG files always expand/shrink (maintaining aspect ratio) to fit  3840w x 6120h max pixels
  - must be 2160h for stereo
  - must be .LE. 3840w for stereo

Other display approaches (Windows)
- Photos, Windows Photo Viewer in full screen mode

File height description:  TBD
Downloadable JPEG Test patterns 1920w x 2160h:
  1-Solid Red
  2-Solid Green
  3-Row Interlace (Red on top)

W10: Right Click on image, and
Save Link As...
When stored as a local file (as on a USB flash drive) on the LeTV and displayed, the Row Interlace (3) file image above will appear a uniform tan as shown by the LeTV photo* to the right -->

When viewed with 3D glasses, the left eye will see solid red, and the right eye will see solid green.

* Overexposed photo darkened with Picasa.
Downloadable JPEG Test patterns1920w x 2150h:
  4-Solid Red
  5-Solid Green
  6-Row Interlace (Red on top)

W10: Right Click on image, and
Save Link As...
When the Row Interlace (6) file image above is stored as a local file on the LeTV and displayed, it will appear a striped tan as shown by the LeTV photo to the far right below.

When viewed with 3D glasses, the left eye will see an alternating red and green pattern of stripes flowing into each other,  red at the top as in the first photo below. Similarly, the right eye will see the the complementary  pattern, with green at the top as in the second photo below.
2150h Test pattern (6) row interlace camera photos* as viewed on Letv:
- Left lens 3d glasses
- Right lens 3d glasses
- no glasses

* Overexposed photos darkened with Picasa.
File width description: TBD
NOTE: The original SBS Stereo photo Aquar_021.jpg taken 8/2/2013 5:34pm, modified here, is provided courtesy of David K. Vail.
Downloadable JPEG row interlaced stereo test scenes:
  1-3840w x 2160h
  2-3843w x 2160h
  3-4146w x 2160h

W10: Right Click on image, and
Save Link As...
Photos of test scene 1: 3840w
 Left: No glasses
 Right: Thru left lens of glasses

Photos of test scene 2:3844w

 Left: No glasses

 Right: Thru left lens of glasses

Photos of test scene 3: 4146w
 Left: No glasses
 Middle: Thru left lens of glasses
 Right: Thru right lens of glasses