High-Definition Multimedia Interface, or HDMI, is found on many pieces of modern consumer electronics audio/video equipment. The promise of a single cable facilitating HD video with uncompressed audio is enticing, eliminating wire nests behind equipment stacks. However, the tolerances for HDMI cables are pretty tight, causing obvious signs of distress on-screen if the cable is going bad.
Sparkles, or "shooting stars" are white and multi-colored dots that manifest on screen if the cable is at or slightly over its tolerance. This normally happens when a lower-gauge HDMI cable is asked to carry a signal 75 feet or more. However, when a short cable causes sparkles, it's typically due to a stressed connector or pin inside the cable's connector that's slightly bent or otherwise damaged. This is usually the most common and telltale sign that a cable is bad or simply of poor quality.
Lack of Control
HDMI's CEC, or consumer electronics control, is a feature that allows HDMI-enabled equipment to communicate with one another. This option negates or reduces the need to make manual settings between sources, receivers and televisions, since the devices will become aware of the others' capabilities once they're powered on. If you have this option enabled in your equipment, you should be able to, for example, turn all system devices on or off with the power button on the remote of one of those devices. Signs that the cable or corresponding pin in the connector of the cable is bad is the loss of this control. Other signs include a random loss of picture, or a CEC-controlled device shutting down unexpectedly.
Turning on a source device and a display should yield an image of some sort, provided the HDMI cable is functioning correctly and you're on the correct input on your television. If you're continually presented with a blank screen, this is often a sign of a bad cable. Try swapping the cable, powering off all devices and turning them back on. This helps to isolate the cable as the culprit.
The solarization phenomenon presents itself as odd and ill-defined coloring of images. Often, this teams with sparkles all over the screen, since the cause is usually the same. Solarization usually looks like a pink, blue, and light green tinge or border on things that shouldn't have them. On-screen items that have a wide array of colors blended into one, such as flesh tones, are the most obvious when the cable is having problems.