Resolution Quality

The resolution capabilities of your camera is a very important aspect to consider. It is fairly well known that higher quality resolutions yield higher quality videos. Most HD video cameras these days come equipped with the ability to take 1080i or better 1080p video quality. So, how then do I go about choosing a resolution that best fits my sign? A good rule to follow when comparing video camera resolution to get the best results is to take the pixel matrix of your sign and multiply it by 4. Example: a 216 x 480 pixel LED Displays would use a camera that could record 864 x 1920. Anything higher would not be noticeable.

The above formula is how to obtain the best results on a LED Screen. If you cannot afford or find a camera that meets those requirements, then a camera that can record in any resolution higher than the pixel matrix of your sign will suffice.

Frame Rate & Shutter Speed

The frame rate and shutter speed of video cameras are often confused as being the same thing. This is not true. The frame rate of a video camera is how often it will take shots in a video. The shutter speed is how fast each shot is exposed to the light. When looking for a good video camera to display it is always better to have higher numbers in both these fields. A frame rate of 60 frames per second (fps) and a shutter speed of 1/120 would be the minimum recommended for live video.

Input Options

There are several ways video cameras can be connected to LED displays. Trying to go over every possibility would futile. Instead, I am going to list the input connections available on a typical video processing unit used with DCI LED displays. This way, you can match the connections with every video camera you are comparing against. You will want to make sure that any video camera you are considering using can output to one of the following connections:

• 3 x Composite (CVBS)
• 1 x Svideo
• 1 x Component (SD/HD)
• 1 x VGA
• 1 x DVI (HDMI 1.3 Compatible)

Stabilization Methods

Another good feature you may want to consider is how stable a camera records. Newer cameras now have built in image stabilization technologies that help offset the shakiness when used handheld. When comparing two cameras against each other I advise researching the reviews of others on their experiences in this field.

If you want to provide your camera with supreme image stabilization, then I suggest investing in a mounting system. This could range from using a tripod to using a bolted camera mount with a swivel arm. In either case, having a stable camera will guarantee that you video has a professional look when recording.

Controls

This is a major area that you will need to look into when selecting a video camera. The one thing I can’t stress enough of is that you WANT the ability to adjust as many settings as possible when using a video camera. The reason you will want to have as many settings available to us as possible is that will allow you the capability to adapt to any environment setting. Whether it is an indoor Basketball game with Low-key lighting, or a big Baseball game on a sunny day. Having the ability to adjust your controls manually will always produce the best video results.

Some of the controls that are essential to be manually adjusted are: Shutter Speed, Aperture Size (IRIS), Resolution (FPS), Focus, and White Balance.

High-end video cameras will allow you to adjust more of the settings listed above. Low-end video cameras have a lot of built in “Dummy” presets and limit the users ability to adjust settings on their own.

What is pixel sharing?

Pixel sharing is the process in which adjacent pixels share diodes when displaying images, video, or text. There are two main ways in which this is attempted.

The first, is the idea is that if two pixels could share diodes, they would be able to duplicate twice the resolution by creating a virtual pixel. The problem is when sharing diodes, one of the pixels will always be absent a diode needed to produce a color. Even worse, if the virtual pixel uses diodes from both pixels, neither of orginal pixels will be able to produce the same color.  In LED technology, a single full color needs at least 1 Red, 1 Green, and 1 Blue diode to produce a spectrum of colors. If even just one of those colors is taken from a pixel and used for another pixel, the original pixel can no longer produce that color. Ultimately using 2 pixels to produce the results of 1 pixel.

The second method uses a software program to alternate the same image back and forth between the pixel and the virtual pixel. The software tries to shift the picture fast enough that they hope the viewer will not notice. The problem with this method is that not only does it induce flickering which could cause epileptic seizures, but it also uses twice the amount of power in order to keep up the flickering. Often, these signs wil burn out in twice the amount of time of a normal LED display.

Why doesn’t pixel sharing work?

There are two primary reasons why this type of technology is flawed. The first problem deals with color distortion. If you try to display an image twice the size of the actual resolution of the sign, the sign has to make a choice. For every two pixels on the image, it has 1 pixel on the sign. So it will often choose the color that lies between the two original colors. Often, this is a color that you did not plan for or want displayed. When chosing between Bright Blue and Black, you might end up with a Dark Blue instead.

The second problem lies in when the display is forced to choose one pixel over another and it decides to use the virtual pixel to fill one of those pixels. The result is the first pixel never gets its actual color, the second pixel is displayed fine, but the third pixel in the line also does not get its full color. At that point even though the display thinks it is using all the pixels, the display is showing wrong colors, and an even greater reduced resolution than if someone had just created the image at the actual resolution. You basically go from thinking you are displaying an image at 200% the resoltuion down to only 75% of the original.

Bottom line.

Datatronic uses only the actual pixel resolution with all of our LED Displays. We do not believe in deceiving customers by tricking them with methods such as Pixel Sharing. Competitors will often sell their displays showing double the actual resolution of a sign, use it as a key point, and try to confuse the customer by stating it is possible with Pixel Sharing. They hope to confuse you with only telling you that it shares pixels, but not the full details on how it warps images, text, and videos.