Giophone

LG TV Quirks II Anamorphic Video Flag

LG TV Quirks II Anamorphic Video Flag

Before getting into the details, readers should know that this post is about the LG TV built in video player (firmware) for streaming DLNA content. Particularly, this is what I have found out so far regarding the LG TVs inability to recognize the "anamorphic" flag in video content that should result in the video player stretching the width of the pixels to fill the screen side-to-side. This really only applies to video content that carries the "anamorphic" flag so it mostly affects people who are attempting to re-code their DVD collection into video files that can be streamed from a DLNA server. I had hoped that sometime during the past year, LG would update the firmware on the TV and fix the DLNA video player, but as of firmware version 5.00.04, it is still not fixed.

Now for some details...

Background

This issue occurs when the LG TV attempts to play HD (16:9 ratio / wide-screen) content which has been recoded (not recorded... recoded) from DVD media to a mkv, m4v or mp4 video file using a tool like Handbrake. DVD content is always stored as a 720:480 picture which was originally intended for the 4:3 aspect ratio typical on tube TV sets that were most common when DVDs were introduced.

You might be wondering why the picture size is 4:3 when the numeric ratio is 3:2. It doesnt exactly work like that because only the width (720) is a pixel-count resolution. The height or "y" dimension is a scan-line count. Those old tube TVs show scan lines taller than each of the pixel dots across the line, so theyre not square... but I digress.

Over the past few years, HD, which is intended to be displayed on a wide screen at a 16:9 aspect ratio has taken over as the standard picture size. HD flat screen TV sets and projectors (e.g. "Full" HD 1080i/p at 1920:1080 or 720i/p HD at 1280:720) have become far more common. Nearly all TV series seasons/collections of recent shows are published on DVDs which are "rigged" to display the 720 pixels in each line wider (instead of narrower). Some older DVDs delivered the wide-screen picture ratio by including actual black bands above and below the viewable picture area. (Some DVDs of movies that have an original aspect ratio that is wider than 16:9 still do this.) Including the black bands in the picture in order to deliver the correct aspect ration diminishes the overall quality because it uses only part of the available height for actual picture data (the black band part) is just discarded.

To improve the picture quality, most recent DVDs, especially those with HD TV content, carry a special flag on the video stream that tells the player how to stretch the pictures width to reproduce the original picture size. This allows the picture to be stored on the DVD at the full height, without the wasted "black band" areas. The stored picture is squeezed from side to side to fit within the 4:3 picture ratio so that when the player stretches it back out to 16:9, it looks right again.

The problem with the LG TV (at least the 5500 / 5600 / 5700 models) is that the video player ignores that flag and DOES NOT STRETCH THE PICTURE AS IT SHOULD. As a result, the picture displayed on the LG TV appears squeezed from side to side.

It looks like LG TV owners are just out of luck on this issue. Samsung TVs seem to handle the anamorphic video flag in content just fine. Set top boxes like the WD TV Live also stretch the video to the proper size. It appears to be a problem that only the LG TV, maybe only the 55LW5700, but probably most of the LG TVs that are ironically marketed under the "SMART TV" logo.

Solution(s)

Since it doesnt look like LG will ever get this fixed, their TV sets just wont correctly display any video content that is originally from a DVD if the content is in HD / wide screen format. In other words, if the video content is encoded such that it depends on the video player recognizing the anamorphic video flag to properly re-size / stretch the picture, LGs built in player isnt up to the job.

Solution 1 is to just abandon the built in player and buy a set-top streaming box like a WD-TV Live. The HDMI output from a box like that will fill the screen as it should without requiring the source video file (m4v, etc.) to be recoded.

Solution 2 is to recode all the content with the anamorphic flag disabled. This requires some investigation of what the proper size ratio of the picture should be for each DVD and requires manually setting the output picture size in the recoding tool (at least in Handbrake). If you already have a large amount of recoded content that would need to be recoded, this isnt a very attractive option. Recoding video including a physical re-sizing of the picture dimensions is time consuming and requires a great deal more computer processing power than a typical straight-through, frame-by-frame picture transcode.

References:

* http://forum.videohelp.com/threads/329912-MKV-Anamorphic-Problem-Encoding-In-Handbrake
* http://en.wikipedia.org/wiki/Anamorphic_widescreen
* http://forum.serviio.org/viewtopic.php?f=12&t=2334
* https://trac.handbrake.fr/wiki/AnamorphicGuide
* http://www.lg.com/us/smart-tvs
* http://www.amazon,com/s/ref=nb_sb_noss_1?field-keywords=wd%20tv%20live
* http://en.wikipedia.org/wiki/Display_resolution
* http://forums.plexapp.com/index.php/topic/26123-supported-file-formatscodecs/

visit link download