There are several types of video-conferencing depending on:
Type of network over which information travels. In this classification, we find two types of videoconferencing:
Video conferencing over ISDN . To carry out videoconferences ISDN (ISDN) is necessary to have lines of this type which is not commonplace. The lines dedicated to videoconferencing traffic and be a direct channel between the participants, the speed of connection is established the videoconference is fixed and doesn't fluctuate which ensures a minimum quality throughout the development of the event. It is advisable to have at least 3 ISDN lines (128 Kb * 3 - > 384 Kb of bandwidth) to have a good user experience. Today are very few video conferencing that uses this type of connection due to its cost, low quality and the need to have these ISDN lines. The meeting room by the computing service-based videoconferencing has with this type of ISDN lines as well as the necessary equipment to carry out video conferences of this type if necessary.
Videoconferencing over IP networks . For several years it is the most used system to carry out videoconferences since the speed of connection to Internet, especially between centres such as universities, are high and stable enough to replace the connections over ISDN. It is usual to make IP video conferencing from 768 Kb up to 2 Mb depending on the type of connection of the participating centres offering very high quality audio, video and data. All the rooms's videoconference that offers this service are teams of IP videoconferencing with speeds of up to 4MBs.
System or protocol used for the realization of the videoconference. There are several ways of establishing a video conference ranging from:
Video conferencing with desktop applications such as ISL , Adobe Connect , Skype , Polycom PVX , Google Talk , etc. Such systems tend not to use protocols or standard codecs and offered quality tends to be very low. They fit well for daily videoconferences. UA video conferencing service provides service for this type of video conferencing using Adobe Connect .
Video conferencing with professional videoconferencing systems such as Polycom , Tandberg , Sony , Lifesize , etc. They are videoconference systems Yes using audio codecs and protocols of communication (H320, H323, SIP) and standard video (H263, H264, AAC) and that are normally implemented in dedicated videoconferencing hardware computers. Normally all University organizations have such equipment which ensures interoperability and quality. All the rooms of videoconferencing offering this service have such equipment.
Number of participating sites. According to this classification, we find:
Video conferencing point to point . They are videoconference involving only 2 sites.It is not necessary to have any additional equipment for videoconferences of this type.
Video conferencing multipoint . They are videoconference involving more than 2 sites. In this case it is essential to have a team that makes central unit (MCU) which they call everyone. This team is responsible for distributing the image and sound for all to all.
In this type of video conferencing should decide how we want the MCU to distribute video and audio received previously. This decision is made depending on the type of video conferencing and the following 2 options exist:
Type presentation . One of the sites involved in the videoconference acting as keynote speaker while the other sites just listen or make specific, short-term interventions. This is the case of a class or of a paper where there is a keynote speaker (the teacher or the Rapporteur) and several sites following his talk. In this mode, all the participants see and hear only the video and audio of the site to act as keynote speaker. The MCU choose automatically who is the keynote speaker by selecting the site which come le audio signal continuously. If any of the other participating sites want to take control of the video so that you see the rest of sites, so just start talking.
Type discussion . All sites are involved at the same level and one or other interventions may be inserted spontaneously. This is the case of a coordination meeting. In this mode, the MCU receives the audio and video of all participants, une video of each one of the signals by composing a mosaic and blend all the audio signals and this is what sends to each and every one of the participants. In this way, all the sites see and hear at the same time to all other participating sites.
Computing Service of videoconference service
Universidad de Alicante Carretera de San Vicente del Raspeig s/n 03690 San Vicente del Raspeig Alicante (Spain)