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Position:IcFull.com » IC Electronic information » Category: F

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Full resolution HD video conferencing technology

In Electronic Infomation Category: F | on December 28,2010

HD video closer and DG538ADN datasheet and closer, in video conferencing, the company also hit the "HD" concept, then the high-definition video conferencing in the end what is it? Presumably some of the novice, may be a more vague, the following us from the concept of high-definition video, high definition video conferencing standard, high definition video conferencing and DG538ADN price and the difference between HDTV, HD video conferencing technical requirements, the advantages of five high-definition video conferencing aspects in detail about:

First, what is high-definition video

everyone is familiar with standard definition (SD) analog TV. This is what we know and DG538ADN suppliers and has been used for decades on television. NTSC format (for North America and other regions) level of resolution of 525 lines, 30 frames per second. PAL (used in other parts of the world), compared with 625 lines, 24 frames per second picture. First still picture of the odd-numbered scan lines, and then scan the same image information in the even lines. As a result, two images will also be displayed on the monitor, also known as 50/60 per second field. The odd / even interlaced scan mode is called, the technology has been developed to save transmission bandwidth (network connection-specific data rate capacity.) This resolution is known as 480i, provide different information from the 240 line screen composition. SD for the broadband household demand for 45-90Mbit / s.

video display for a small (less than 27 inches), standard definition TV looks fairly clear, smooth. However, if the screen over 27 inches, 480i format, image quality will be significantly reduced. May also see jagged lines, the outline blurred, faded, visual noise and intermittent action.

progressive scan mode, as an alternative to interlaced scanning technology improves the picture quality on the big screen. 480 line progressive scan technology will be merged into one line of image information frame, and then automatically corrects picture quality. Progressive reduction of the teeth on the big screen motion picture screen and to become more fluid. This resolution of standard definition TV is known as 480p.

true high-definition video display image resolution is 1080i or 720p, the resolution of other high-definition is not real. HD format image information than any SD format to be more. If the screen resolution is converted to pixels, you can clearly see the HD format offers higher than the 480i format images at least 4 times more information.

to intuitively understand the difference between them can imagine the TV screen computer monitor. Imagine the 640 X 240 (equivalent to 480i) stretch in the low-resolution digital images on the 42-inch screen will be what effect. The image will be distorted because of low-resolution images did not provide enough high-quality view of the need for more image information. High-resolution format with the higher number of pixels to improve the picture quality, so that the picture on the big screen appear to be more clear, smooth. In video conferencing, this technology can improve the overall viewing experience and eliminates meeting fatigue. Colors are more vivid and real, clear and smooth movements.

Second, high-definition video conferencing standard

in HD encoding / decoding technologies used to produce before the video conference data is based on the common interchange format (CIF) encoding. International Telecommunication Union - Telecommunication Standards Division (ITU-T) developed a video standard called H.261, and H.263. H.261 standard only defines the format of QCIF and CIF. Quarter CIF (QCIF) format is used only for the minimum data rate (64 kbit / s and below) of the meeting, is now rarely used. Since the H.263

standards since the release, and more using the "full resolution" (defined as 16CIF) formats (4CIF and 16CIF) gradually being adopted. As a result of these standards, computing and bandwidth constraints, for full-motion video conferencing is still a common resolution of CIF to 4CIF.

ITU-T has recently adopted a new standard for video compression, this method reduces the size of the entire video file, so files can be more economically by a smaller-capacity network connection (the lower data rate / bandwidth) for transmission. Now, ITU-T recommendation H.264 high-definition video conferencing with video standard, which is relatively low by providing high-quality data transfer rate of the screen. Now, H.264 has become the HD-DVD (HD DVD) as well as broadcast, cable, videoconferencing and consumer electronics products, mandatory standards.

H.264 technology is ideal for video conferencing. While with previous H.26x algorithm, it needs more processing performance, but after 2004 the production of most of the video conferencing systems, including H.264. It provides high-quality video transmission and low latency encoding and decoding, so that the video stream is more fluent, natural. In fact, H.264 H.263 efficiency is twice the rate in a particular line have twice the video quality. In addition, some enhanced H.264 technology also includes interactive video error concealment algorithm, this technology can automatically adjust the video processing, even in the network overload, unstable, or an error rate of the circumstances, to ensure that operations can be freely and provide higher quality visual enjoyment.

H.264 coding standard provides greater flexibility for developers to provide a different common platform interoperability. H.263 standard supports many different versions, but contains only very few H.264 standard compression techniques. This way, you can reduce the video quality is not obvious under the premise of more easily multi-manufacturer integration of different video conferencing equipment.

three high-definition video conferencing and high-definition TV the difference

HDTV is one-way broadcast television network one-way transmission (broadcast) video. HD Video conferencing is a two-way, interactive process, in the network in real time, two-way transmission of audio and video data. To achieve high definition video conferencing technology, meeting all the terminals must support high definition.

high-definition television signal quality can be kept constant, while the quality of video conferencing may be because the network transmission of large amounts of data and reduced. Encoding / decoding process and transfer large amounts of data through the network time consuming process may cause delay. Too much delay will increase the chance of overlapping speech, and may result in video and audio are not synchronized. Long time delay can be clearly demonstrated through the audio out of poor quality will seriously affect the overall sound experience, the overall quality of video conferencing.

four, high-definition video conferencing technical requirements

high-definition video conferencing requires all the terminals are HD compatible device, so that all video conference participants can enjoy high-definition video. All terminals must support the HD compression, in addition, to achieve high-quality video conferencing, broadband internet is also an indispensable factor. High definition interactive video conferencing requires a minimum data transfer rate of 1Mbit / s. For best results, we recommend the data transfer rate at or above 2Mbit / s, by increasing the bandwidth, get the best audio quality and additional content sharing devices such as PC input, DVD or high-resolution camera device text. Network QoS is necessary, it can guarantee stability during the video conference results.

order to obtain high-resolution images, you need to configure support for true 16:9 high-definition standard (minimum 720p) camera. Camera and video conferencing terminals preferably from the same manufacturer. This ensures that the camera functions and terminals that optimize the end to get the best high-definition video conferencing experience.

high-definition video display (LCD, plasma or projector) must support a minimum horizontal resolution of 720p. In addition, the monitor should be equipped with the best high-definition signal support interfaces such as DVI-I digital interface or input interface component YPrPb. More than 5 meters of the DVI cable the picture quality may cause unpredictable attenuation or video display error. Buy high-quality high-definition displays and terminals to avoid such problems.

choose the right monitor, and need the room size and the average distance from the screen was consistent. In the large conference room, was the distance from the screen 3 to 5 meters, such a case, the proposed purchase of at least 50-inch monitor.

in the high-resolution multi-point video conferencing, at least two groups of participants from different locations to (terminal) attended the meeting, this time HD MCU need to bridge all of the calls. Of course, MCU must support true HD (at least 720p) for 30 frames / sec, so as to enable multi-point video calls to the call results. We propose to purchase from the same manufacturer, and video conferencing MCU terminal equipment, so as to ensure the best end to end performance. Finally, MCU must be the standard (H.264) products, in order to achieve interoperability and scalability to meet multi-point calls as much as possible.

five, the advantages of high definition video conference

high-definition video conferencing technology has many advantages. First of all, clear picture quality, synchronized audio and minimum delay to help participants stay focused and to provide efficient, high-quality video conferencing experience. For example, in 16:9 aspect ratio display screen image to display a wider perspective so that more of the participants appear in the screen, to ensure that dedicate themselves to the forthcoming meeting.

Second, the ability to display high-resolution high-definition content (such as design diagrams, flowcharts, maps or photos), able to rely on visual communication of knowledge workers bring great benefits. For example, HD video conferencing can help doctors living in different places face to face communication, analysis of X-rays, MRI magnetic resonance imaging, ultrasonography, ECG results, or ECG results, based on a lot of details to make a diagnosis. Displayed on the screen and read the PowerPoint slides, Flash presentations, presentations and other training software to avoid visual fatigue and improve work efficiency, and to deepen the impression of the work fun. Combined with the smooth movement so that clear images of the same hearing-impaired participants to more easily identify the sign language.

short, high-definition technology improves voice quality, video conferencing can broaden the exchange of information for extension, for business, distance education, telemedicine, community, government and various charities provide a highly value of communication.

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