Overscanning on HDMI and Component = FAIL!

[elteluk]

Is there any logical reason for the WD TV Live to overscan (or enlarge) all output via HDMI or component video in the latest pre-release?

ALL output from the WD TV Live is overscanned (zoomed in) by about 5% in beta firmware v1.03.38 (and v1.03.35) on all outputs whether HDMI 720p, 1080p or component.

This includes menus, photos and videos. That is to say, everything is zoomed in by about 5% compared with the official firmware (1.0.21).

This has the undesired effect of cropping 5% off the top, bottom and sides of all full-frame video and photo.  In fact, EVERYTHING gets cropped!

I hope that this is a bug that will be rectified in a future release.  However, I’m concerned that that the HDMI overscanning “added” in the pre-release was actually intended by the developers and WD plan to implement in the next official release.

If that is the case, please be advised that this is a BACKWARDS STEP, not an improvement.  Such a feature will be unwelcome by the vast majority of users once they realise that the WD is cropping 5% off the edges of all their videos and photos.

So, please tell me developers - is the HDMI overscanning a bug or a feature?

[mkelley]

Welcome to the forums.

I haven’t used the beta firmware (there’s a reason it’s a beta) but let me ask you this – what is your setting for HDMI?  If set for “auto” (the default) try changing it to the highest setting your display supports and see if it makes a difference.

If it doesn’t please let us know here so we can report it to the WD folks (in case they don’t see this thread).

[elteluk]

Like I said, it doesn’t matter what the display setting is on the WD (720p, 1080p, 12-bit, 8-bit, NTSC, PAL,whatever) the image displayed is slightly zoomed.

This wasn’t the case for any other WD firmware I have encountered - just the last couple of pre-releases.

Rolling back to the official firmware resolves the issue.

Hope this gets through to the developers and that they fix or remove it before the next official release.

[TonyPh12345]

I’m not able to duplicate what you say.   I just tried two units running four different versions of software:

WDTV Live running B-RAD WDLXTV- No Overscan.

WDTV Live running 1.02.21- No Overscan.

WDTV Live running 1.03.38V - No Overscan.

WDTV Live+ running stock firmware- No Overscan.

In my case, these were all HDMI 1080p.

While I believe you do see overscan, I can’t corroborate that it changed after a firmware upgrade, as I see absolutely no difference. 

What’s more likely (as my previous TV did the same thing) is that your display doesn’t support 1:1 pixel mapping.  My new TV does, and now everything displays with ZERO lost pixels all the way around the screen.

I proved this by making a black GIF file that’s 1920x1080 resolution, and set a one pixel white border all around the edge.  I can see the white border on all four edges.

[TonyPh12345]

…and by the way, my previous set, an LG 32LC2DU, also exhibited about a 5% overscan, but it did that for everything; no support for 1:1 pixel maps.

My new TV is an LG 55LX6500, and by DEFAULT, has a 5% overscan on HDMI modes, but there’s a mode than can be set called “Just Scanning” that enables 1:1 pixel maps.

[Guy_K]

There should not be any overscan in HDMI unless your TV is overscanning. We have not seen any differences in HDMI overscan between the different firmware revs in our own testing. We have some TVs that overscan HDMI, but they do so regardless of firmware rev. Please do provide more information if you can - TV make and model, what the TV’s settings are, and anything else you can think of. Photos would be helpful too. Thanks.

[elteluk]

Thanks so much for looking into this.  I didn’t expect such a thorough and quick response!

Glad to hear that you couldn’t re-create the problem at your end which means that it’s probably an issue with my model of TV.  I need a good excuse to buy a new one!

My TV is a 720p LCD Toshiba model 32AV555D.  It’s a basic, low-end model from last year and was quite popular.  It has no overscan adjustment available.

It’s frustrating that the HDMI overscanning only happens with the pre-release firmware installed.  Perhaps the problem has something to do with the changes in HDMI handshaking that were added to the firmware recently.

For the record, my previous WD HDTV box (the shiny back one without ethernet), doesn’t overscan on this TV either, although both boxes and all firmware overscan slightly when outputting via component.

To be thorough, here are my findings and photos of the screen comparing firmware versions 1.02.21 and 1.03.38_V on the WD TV Live.  The overscan % relates to the outer edge markers in the test card image at the bottom of this post.

Using version 1.02.21:

Composite (PAL & NTSC): Overscans by 2.4%

HDMI (at every setting): no overscanning 

Using version 1.03.38_V:

Composite (PAL & NTSC): Overscans by 2.4%

HDMI (at every setting): Overscans by 2.6%

The next two photos demonstrate how the output is slightly magnified on my TV in the current pre-release compared with the official release.  Notice the relative position of the circles in the background.  In both shots the output is HDMI 720p 50Hz.

So I guess I need a new TV, huh?

[elteluk]

I just plugged an xbox 360 into my TV and played the same test card I used for the WD Live and it also appears to overscan at 2.6%, the same as the newer WD Live firmware.

So maybe when a “proper” HDMI handshake takes place, the Toshiba panel overscans,  e.g. xbox 360 and the latest WD Live firmware. But when there is a less sophisticated HDMI handshake there is no overscan on the Toshiba panel e.g. older WD Live firmware, earlier WD TV box.

[elteluk]

A few more images:

1. Test image used

2. Using older WD firmware

3. Using newest WD firmware

[TonyPh12345]

I’m anxious to see the pics.  Unfortunately, we have to wait for a moderator to approve them before they become viewable by anyone but yourself…

As to needing a new TV?   Well, of course, that’s up to you.   But just keep in mind that ALL Studios… motion picture, TV, whatever, take into account Overscan in final production.   

Check out the Wikipedia article on what’s called the Broadcast Safe Area.

So, you’re really not missing anything “important” in the movies and shows…

[mkelley]

elteluk wrote:

So maybe when a “proper” HDMI handshake takes place, the Toshiba panel overscans,  e.g. xbox 360 and the latest WD Live firmware. But when there is a less sophisticated HDMI handshake there is no overscan on the Toshiba panel e.g. older WD Live firmware, earlier WD TV box.

Except that when you set the resolution yourself I’m surprised that any handshaking is then done.  I’m not saying you’re wrong, because it does appear that’s what’s happening, but it’s too bad there isn’t a “use this mode irregardless of what my TV reports back” that you can use.

As Tony says, you’re not missing much (although I’d guess offhand that with your own still images you DO miss something that might be significant depending on how you made them).  Overscan has been around forever and I suspect it will still be many decades before television producers ever consider eliminating it (although Tony is wrong in one regard despite what any Wiki “authority” might say – movie makers don’t think much, if anything, about overscan.  I’ve worked in that industry and it never comes up at all).

[richUK]

The movie business may not talk about ‘overscan’ but I’m sure they use ‘action safe areas’ which are basically the same thing.

[elteluk]

Overscan will almost certainly become a non-issue as CRT TVs are phased out.  More and more panel-makers will make perfect pixel mapping the default rather than as an option and TV programme makers will no longer need to consider safe arees when shooting and editing.  Thankfully!

However, for the time-being, you are correct that I won’t miss out on much regarding the current TV and film output.

Unfortunately, video makers uploading to the web don’t take into account safe areas as the content will typically be played back on a monitor.  I have downloaded and watched a number of videos where text has been cropped in the pre-release due to it’s positioning right at the edge of the frame.

Still, no big deal.  And, like I said before, my panel is a cheapie that needs replacing anyway!