| Foreword: For many years, the video conferencing system has become one of the important criteria for measuring the compliance of many units in information construction. However, in the units that have actually applied video conferencing, they often hear complaints about the difference between the application effect and expectations. What hinders the situation? What is the development of video conferencing? Some surveys show that clarity, delay, bandwidth, stability, high prices and operators' promotion models are all important factors hindering the development of the video conferencing industry. The most powerful issue is the clarity of the video. |
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High-definition video
Everyone is familiar with standard definition (SD) analog TV. This is the TV we know and have been using for decades. The NTSC format (for North America and other regions) has a horizontal resolution of 525 lines and 30 frames per second. The PAL system (for the rest of the world) is 625 lines, 24 frames per second. The odd lines of the still picture are scanned first, and then the even lines of the same picture information are scanned. In this way, the two images will be displayed on the display at the same time, also known as 50/60 fields per second. This odd/even scan mode is called interlaced scanning and was developed to save transmission bandwidth (data rate capacity for a particular network connection). This resolution, called 480i, provides a picture of 240 lines of different information. The broadband requirement for home standard definition is 45-90 Mbit/s.
For small video displays (less than 27 inches), SDTV looks quite clear and smooth. However, if the screen is more than 27 inches, the image quality in the 480i format will drop significantly. You may also see jagged lines, blurred outlines, fading, visual noise, and intermittent motion.
The progressive scan mode, as an alternative to interlaced scanning, improves picture quality on large screens. Progressive scanning combines 480 lines of image information into one frame and automatically corrects the picture quality. Progressive scanning reduces the jagged image on the large screen and makes the picture motion smoother. This resolution of SDTV is called 480p.
True HD video displays image resolutions of 1080i or 720p, while other resolutions are not true high definition. The HD format provides more image information than any SD format. If you convert the screen resolution to pixels, you can clearly see that the HD format can provide at least 4 times more image information than the 480i format.
To visually understand the difference, imagine the TV screen as a computer monitor. Imagine how it would be to stretch a 640 X 240 (equivalent to 480i) low-resolution digital image onto a 42-inch screen. The image will be distorted because there is not enough image information in the low resolution image to provide the high quality view. The higher pixel count of the high-resolution format improves picture quality and makes the picture on the large screen clearer and smoother. In video conferencing, this technology can improve the overall visual experience and eliminate meeting fatigue. The color is also more vivid and true, and the movement is clear and smooth.
Standard for high definition video conferencing
Video conferencing data is encoded based on the Common Interchange Format (CIF) prior to the generation of HD encoding/decoding techniques. The International Telecommunication Union-Telecommunication Standards Department (ITU-T) has developed video standards called H.261 and H.263. The H.261 standard only defines the QCIF and CIF formats. The quarter CIF (QCIF) format is only used for conferences with the lowest data rate (64 kbit/s and lower) and is currently rarely used. Since the release of the H.263 standard, more formats using the "full resolution" (defined as 16CIF) (4CIF and 16CIF) have been adopted. Due to the limitations of computing and bandwidth when using such standards, the common resolution for full-motion video conferencing is still CIF to 4CIF.
ITU-T recently adopted a new standard for video compression that reduces the size of the entire video file so that files can be transmitted more economically over smaller network connections (lower data rates/broadband). ITU-T now recommends high-definition video conferencing using the H.264 video standard, which provides high-quality images with relatively low data rates. Today, H.264 has become a mandatory standard for HD-DVD (HD DVD) as well as broadcast, cable, video conferencing and consumer electronics.
Everyone is familiar with standard definition (SD) analog TV. This is the TV we know and have been using for decades. The NTSC format (for North America and other regions) has a horizontal resolution of 525 lines and 30 frames per second. The PAL system (for the rest of the world) is 625 lines, 24 frames per second. The odd lines of the still picture are scanned first, and then the even lines of the same picture information are scanned. In this way, the two images will be displayed on the display at the same time, also known as 50/60 fields per second. This odd/even scan mode is called interlaced scanning and was developed to save transmission bandwidth (data rate capacity for a particular network connection). This resolution, called 480i, provides a picture of 240 lines of different information. The broadband requirement for home standard definition is 45-90 Mbit/s.
For small video displays (less than 27 inches), SDTV looks quite clear and smooth. However, if the screen is more than 27 inches, the image quality in the 480i format will drop significantly. You may also see jagged lines, blurred outlines, fading, visual noise, and intermittent motion.
The progressive scan mode, as an alternative to interlaced scanning, improves picture quality on large screens. Progressive scanning combines 480 lines of image information into one frame and automatically corrects the picture quality. Progressive scanning reduces the jagged image on the large screen and makes the picture motion smoother. This resolution of SDTV is called 480p.
True HD video displays image resolutions of 1080i or 720p, while other resolutions are not true high definition. The HD format provides more image information than any SD format. If you convert the screen resolution to pixels, you can clearly see that the HD format can provide at least 4 times more image information than the 480i format.
To visually understand the difference, imagine the TV screen as a computer monitor. Imagine how it would be to stretch a 640 X 240 (equivalent to 480i) low-resolution digital image onto a 42-inch screen. The image will be distorted because there is not enough image information in the low resolution image to provide the high quality view. The higher pixel count of the high-resolution format improves picture quality and makes the picture on the large screen clearer and smoother. In video conferencing, this technology can improve the overall visual experience and eliminate meeting fatigue. The color is also more vivid and true, and the movement is clear and smooth.
Standard for high definition video conferencing
Video conferencing data is encoded based on the Common Interchange Format (CIF) prior to the generation of HD encoding/decoding techniques. The International Telecommunication Union-Telecommunication Standards Department (ITU-T) has developed video standards called H.261 and H.263. The H.261 standard only defines the QCIF and CIF formats. The quarter CIF (QCIF) format is only used for conferences with the lowest data rate (64 kbit/s and lower) and is currently rarely used. Since the release of the H.263 standard, more formats using the "full resolution" (defined as 16CIF) (4CIF and 16CIF) have been adopted. Due to the limitations of computing and bandwidth when using such standards, the common resolution for full-motion video conferencing is still CIF to 4CIF.
ITU-T recently adopted a new standard for video compression that reduces the size of the entire video file so that files can be transmitted more economically over smaller network connections (lower data rates/broadband). ITU-T now recommends high-definition video conferencing using the H.264 video standard, which provides high-quality images with relatively low data rates. Today, H.264 has become a mandatory standard for HD-DVD (HD DVD) as well as broadcast, cable, video conferencing and consumer electronics.
Everyone is familiar with standard definition (SD) analog TV. This is the TV we know and have been using for decades. The NTSC format (for North America and other regions) has a horizontal resolution of 525 lines and 30 frames per second. The PAL system (for the rest of the world) is 625 lines, 24 frames per second. The odd lines of the still picture are scanned first, and then the even lines of the same picture information are scanned. In this way, the two images will be displayed on the display at the same time, also known as 50/60 fields per second. This odd/even scan mode is called interlaced scanning and was developed to save transmission bandwidth (data rate capacity for a particular network connection). This resolution, called 480i, provides a picture of 240 lines of different information. The broadband requirement for home standard definition is 45-90 Mbit/s.
For small video displays (less than 27 inches), SDTV looks quite clear and smooth. However, if the screen is more than 27 inches, the image quality in the 480i format will drop significantly. You may also see jagged lines, blurred outlines, fading, visual noise, and intermittent motion.
The progressive scan mode, as an alternative to interlaced scanning, improves picture quality on large screens. Progressive scanning combines 480 lines of image information into one frame and automatically corrects the picture quality. Progressive scanning reduces the jagged image on the large screen and makes the picture motion smoother. This resolution of SDTV is called 480p.
True HD video displays image resolutions of 1080i or 720p, while other resolutions are not true high definition. The HD format provides more image information than any SD format. If you convert the screen resolution to pixels, you can clearly see that the HD format can provide at least 4 times more image information than the 480i format.
To visually understand the difference, imagine the TV screen as a computer monitor. Imagine how it would be to stretch a 640 X 240 (equivalent to 480i) low-resolution digital image onto a 42-inch screen. The image will be distorted because there is not enough image information in the low resolution image to provide the high quality view. The higher pixel count of the high-resolution format improves picture quality and makes the picture on the large screen clearer and smoother. In video conferencing, this technology can improve the overall visual experience and eliminate meeting fatigue. The color is also more vivid and true, and the movement is clear and smooth.
Standard for high definition video conferencing
Video conferencing data is encoded based on the Common Interchange Format (CIF) prior to the generation of HD encoding/decoding techniques. The International Telecommunication Union-Telecommunication Standards Department (ITU-T) has developed video standards called H.261 and H.263. The H.261 standard only defines the QCIF and CIF formats. The quarter CIF (QCIF) format is only used for conferences with the lowest data rate (64 kbit/s and lower) and is currently rarely used. Since the release of the H.263 standard, more formats using the "full resolution" (defined as 16CIF) (4CIF and 16CIF) have been adopted. Due to the limitations of computing and bandwidth when using such standards, the common resolution for full-motion video conferencing is still CIF to 4CIF.
ITU-T recently adopted a new standard for video compression that reduces the size of the entire video file so that files can be transmitted more economically over smaller network connections (lower data rates/broadband). ITU-T now recommends high-definition video conferencing using the H.264 video standard, which provides high-quality images with relatively low data rates. Today, H.264 has become a mandatory standard for HD-DVD (HD DVD) as well as broadcast, cable, video conferencing and consumer electronics.
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December 22, 2020