In order to make Skype HD (high-definition) calls, you need to have some requirements, including a good web came, a powerful computer etc. Among these is sufficient bandwidth, meaning an Internet connection that is speedy enough to carry the bulk of video frames.
Video is actually a succession of images (called frames) defiling in front of the eyes at an average speed of 26 frames per second. You can imagine the amount of bytes one second of video represents, compared to a single picture or a page of text. Now, HD (high definition) video means that the frames have higher resolution, more details, and therefore are more bulky in terms of bytes. This considerably increases the size of each second of video. Therefore, you have all the necessary equipment for HD video calling with Skype, but if you don’t have enough bandwidth, you will never get the clear, crisp and bright HD video quality.
How much bandwidth is enough? For simple video calling, 300 kbps (kilobits per second) is largely sufficient. For HD video, you need at least 1 Mbps (Mega bits per second), and are sure to have good quality with 1.5 Mbps. That’s for one-to-one conversations. How about when there are more participants? Add another 1 Mbps per added participant for comfortable video conferencing. For example, for a group video call with 7-8 persons, 8 Mbps should be largely sufficient for HD video quality.
To have a better idea, you can check how much bandwidth a video call is using. During an HD video call, click Call in the menu bar and select Call Technical Info. A window appears with details about the bandwidth consumption. Notice that the unit is in kBps, with a B in uppercase. It stands for Byte. You will have to multiply that value by 8 to get its equivalent in kbps (with small letter b), because a byte contains 8 bits. Both the upload and the download bandwidths are given. For versions earlier than 5.2, the Call Technical Info option is disabled by default. You have to change the settings to display it before starting your call.