Frequently Asked Questions - Audio / Visual
Questions specific to troubleshooting audio and video issues. Click on a question to show or hide the answer.
The ZvBox is broadcasting in “compatibility mode”. That means it’s receiving a picture resolution from your VGA source that doesn’t match a standard 1280 x 720 or 1920 x 1080 HDTV picture resolution.
When that happens, the ZvBox fits the incoming picture inside either a 1280 x 720 window, or a 1920 x 1080 window, each with black bars around the outside. It uses the smallest HDTV-sized window that will fit the image, so the image takes up as much of the screen as possible. See the diagram for an example:
ZvBox then broadcasts the 1920 x 1080 or 1280 x 720 window, with the image contained within, which is “compatible” with HDTVs. To resolve the issue, set your VGA source to output 1280 x 720 resolution, and see this question for how to fine-tune the picture size if needed.
Simply run the “video calibrate-vga” command using ZvCli software. First, make sure the VGA source is delivering a light-colored picture; ZvBox uses the difference in contrast between the picture and non-picture area to calibrate positioning of the image on-screen. Note that this command optimizes a ZvBox for a given VGA resolution, so unless you change your VGA resolution, you can calibrate once and forget it.
For example, when I show my computer’s desktop on-screen, the “Start” button is missing.
Your HDTV is the culprit here. Most HDTVs don’t show a full 1280 x 720 or 1920 x 1080 picture. Instead they mask off the picture’s edges to keep you from seeing the area beyond. The amount of picture masked off (the spec is called “overscan”) can range from 0-15%, meaning your 1920 x 1080 HDTV could be delivering a picture as small as 1632 x 918! To compensate, you can set your VGA source to a slightly lower “underscan” resolution that ZvBox will recognize. That will allow your TV to show a screen-filling picture, without masking off anything important like the start bar.
ZvBoxes have two preset underscan resolutions that they will recognize from a VGA source: one for 1280 x 720 sources, and another for 1920 x 1080 sources. If the preset underscan resolutions don’t result in a screen-filling picture, the ZvCli user manual, page 6, will show you how to employ others, so that your source is able to generate a picture that fits well on-screen.
Tip: ZvBoxes can generate a test image showing the resolution your HDTV is actually displaying, which will tell you which underscan resolution to use.
Sources with 480i output signals are sometimes slightly distorted. Full support for 480i input signals is coming in a firmware update.
ZvPro 250 supports Dolby Digital, PCM, and analog audio inputs. Check to make sure that your DVD player is set to deliver one of those options.