Unlike the analog cables, the HDMI interface transmits digital data only and in most cases, the cables deliver perfect picture quality or no picture at all. When there is no picture, then there could be a number of problems causing the problems, but most of these problems are caused by incompatible devices rather than the cable itself. When trying to connect non-HDMI ready equipment to HDMI display, then you are likely to see no picture and when trying to watch encrypted content, the same problem might arise if your devices do not support the encryption. However, you might have heard that longer HDMI cables could cause some issues and they certainly could, but these issues rarely pertain to the picture quality.
Longer HDMI cables and the issues that you could face when using them:
No picture at all- if you are using a normal length cable (2-3 meters long), then you are likely to have perfect sound and picture as long as you have HDMI-ready source and display. However, if you run say 10 meters long HDMI cable, this might work in some setups and might not in others. The fact is that different manufacturers and even different equipment from the same manufacturers could have different strength signal. When choosing a longer HDMI cable, you should look for one that has Category 2 specification since it is less likely to present problems. It is also good to consult the manufacturer or the retailer since some Category 2 cables support the specifications only over shorter distance. In addition, you would want higher grade cable, especially if you intend to running in-wall installation – the price is not an accurate indicator of the quality of the cable and even an HDMI cable that costs twenty to thirty pounds would be perfect for most setups. The cheapest cables that you can find cost just a few pounds, but they are thinner and built from low quality materials, which makes them more likely to fail.
For distance of up to 10 meters, you could find a single cable that might work, especially if you purchase one that comes with built-in boosters. For distances over 20 meters, you could purchase two HDMI cables and an HDMI repeater, and for even larger distances, you could chain-run a few HDMI cables. For professional setups that require a few hundred meter cabling, using an optical fiber extender is likely to be the best choice since they could extend the cables over 300 meters.