The application of videoconferencing will be transformed from professional to consumer. This has become the consensus in the industry. Telemedicine, online classrooms, and online recruitment have been integrated into the lives of ordinary people. The increase in industry attention and market demand has led to a rapid development of the videoconferencing industry. Products have sprung up and emerged in an endless stream. This has made ordinary users, who lack general expertise, fall into problems and purchase difficulties.
Video conference audio interference processing
The interference that the audio signal produces in the course of transmission is various, the power interference, inter-equipment interference, light interference and so on are common.
1, power interference. Poor grounding of the power supply, poor ground contact and impedance mismatch between devices, power supply of the device without "cleaning", audio cable and AC wire laying on the same pipe, on the same ditch, or on the same bridge, will cause noise interference to the audio signal. , forming a low-frequency exchange "click" sound.
2. Interference between devices. "Howling" is caused by positive feedback between the speaker and the microphone. The main reason is that the microphone is too close to the speaker or the microphone is pointing to the speaker. The “space noise†is generated by the sound wave delay, if the microphone picks up the sound source signal and picks up the amplified sound recovery signal, or two microphones with different distance from the sound source pick up the signal of the same sound source, or a microphone picks up The signal of another microphone after being amplified will produce a corresponding path difference and cause a delay. When these signals are superimposed, some of the frequency components cancel each other, forming a "space noise."
3, light interference. If the ballast intermittently starts using the ballast, high-frequency radiation will be generated when the lamp is excited, and the microphone and its leads will be strung into the string. “出现†sound will appear; the microphone line will be too close to the lamp line. "Hush" sound. In addition, external high-frequency electromagnetic interference can also occur.
To restore the sound of videoconferencing, according to the theoretical knowledge of acoustics, according to different actual conditions, it is necessary to flexibly adjust the mixing console and equalizer to process and beautify the sound, compensate for the defects of the sound field, and create a more ideal acoustic environment; properly adjust the compression The limiter, which encounters sudden large peak signals, is not overloaded or distorted, and at the same time, the compression limiter is prevented from being compressed for a long time, so that the sound connection is smooth and mellow.
For power interference, the following methods can be used to solve: 1 increase the power filter, use the resonant circuit to filter out harmonics, "purify" the output power; 2 signal input and output lines and power lines are separated, and can not be parallel wiring, to avoid Adjacent and cross-interference, mutual induction; 3 using twisted pair power lines, so that the total flux generated by the two wires cancel each other out.
For the "howling" phenomenon, the following methods can be used to avoid the formation of a natural resonance point: 1 reduce the gain of sound reinforcement; 2 use an equalizer or an automatic feedback suppressor to reduce the amplitude of the "howling" frequency point; 3 connect a frequency shifter or adjust Phaser, use the offset frequency or phase to destroy the in-phase condition of the feedback sound and the sound source; 4 adjust the speaker layout, change the microphone direction, and the distance between the two, to avoid the formation of positive feedback.
For the “space noise†phenomenon, the following methods can be used to avoid acoustic delay: 1 Select a microphone with strong directivity; 2 Turn off the ST switch in the mixer or pull down the extra microphone putter; 3 Adjust the sound source and its amplified sound The proportion of restored sound.
For light interference, the following methods can be used to solve: 1 microphone line away from the light line; 2 microphone line through the tube shielding; 3 using a microphone with strong anti-interference ability.
To sum up, to make video conference better, we must improve the aesthetic appreciation of sound and artistic accomplishment, and conceive and creative sound reduction, in order to improve the artistic expression of sound.
Video conference HD software selection
When the user considers the requirements of the video communication system, the following 10 questions have an important influence on the user's making a correct decision.
(1) Why build a remote video conference system?
Global business is being internationalized, and people need to meet and communicate frequently. Although such expenses, such as differential fee, do not account for a large proportion of the company’s revenue, other invisible factors often have an important impact on the development of the company. Remote video systems can help companies increase production efficiency and capture the market immediately. The trend is to increase the efficiency of the team's collaborative work. These factors are usually extremely important to the company.
For enterprises, the use of video conferencing systems can immediately grasp the market and win competitive advantages. For educational institutions, students and teachers in different regions can be connected to share classroom content and learn from each other. For public agencies, they can provide immediate information, increase safety factors, and provide key communication tools for various emergencies.
(2) Why is HD resolution important in audio and video communications?
The benefits of the videoconferencing software system are that people only see and hear the participants in different areas and feel like they are in a room. At this time, people can appreciate its benefits. But now, due to limitations in processing capabilities, bandwidth, and other factors, video conferencing systems are also limited in quality. In many cases, the "true real-life experience" promised by the manufacturers cannot be fully achieved.
Compared with traditional video conferencing systems, the new high-definition video system solutions can provide 10 times more resolution than systems 10-15 years ago. The resolution of the system is now called FCIF (352 × 288 pixels), and the resolution of the HD system is 1280 × 720 pixels. In the true sense, this is the difference between seeing each other and clearly expressing the other's expression.
For example, in order to be able to make timely decisions as soon as possible, a textile mill that purchases fabrics needs to communicate with the corporate buyer on the other side of the globe. In this process, the clear details and quality of textiles can have a significant impact on the decision-making process.
High-definition, high-fidelity audio communication is also an important factor in ensuring production efficiency. Natural, full-duplex audio quality, covering the entire conference room, so that all participants clearly hear the conference, which is very important. The lack of high-definition audio quality to match video effects will not meet the end user's expectations.
(3) Will the HD system be more expensive?
Compared with the existing video conferencing system, the cost performance ratio of the HD conference system is very competitive. The new system resolution is 10 times higher than the existing system, and the price is similar to that of a general conference system. In addition, the price of high-definition displays is also rapidly falling, and the bandwidth demand for conference calls is also decreasing.
(4) How much bandwidth is needed?
This problem mainly depends on the system that the user plans to use. HD video communication requires a bandwidth of 1 Mbit/s. The previous system bandwidth was 384Kbit/s or 512Kbit/s. Moreover, some companies are using uplink 25Mbit/s (bidirectional) or 2-5Gbit/s to get high-definition video quality. In the past five years, with the popularity of bandwidth, high-quality HD video quality will be more readily available.
(5) Is the HD videoconferencing system compatible with my existing installed videoconferencing system and how can I protect my investment?
First of all, make sure that the system you are currently using is a common standard (like H.264), not some proprietary protocol.
Users all want their systems to maximize their connectivity and connect with more colleagues, suppliers, customers and other companies. One of the issues to be considered is the resolution conversion problem, which ensures that the quality of each system in each call is optimized.
In addition, in any bandwidth situation (either 384Kbit/s or 768Kbit/s), it can provide better video image quality, because the processing and coding capabilities of the new system have been greatly improved.
(6) Can I run high-definition video communications on a standard definition television device display?
In fact, users can run high-definition systems on standard-definition TV screens, but they can't reach the full HD standard of 1280x720.
(7) Can I share multimedia and PC presentations?
In many applications, the ability to share multimedia content and perform PC presentations is an important factor. Users should consider these issues when measuring the system. According to these features, users can connect the PC to the system, plug and play, and can also obtain a high-definition resolution of 16:9 format without any loss of resolution, which is called dual stream. At the same time, it is also extremely important to ensure that multimedia content is compatible with other standards. In addition, you should also consider whether you need to add an additional camera in the application, to display other locations in the room or other participants.
(8) Can the ease of use of the system be improved?
The simplicity and ease of use of the system are usually very important to the user and can greatly increase work efficiency. Interestingly, compared to SD in the 4:3 format, HD in 16:9 format may require constantly moving the camera to see all the participants. Therefore, the transparency of the technology will be very important to the user.
When measuring a system, the ease of use of the system is crucial in initiating calls, multiple calls, running cameras, and sharing multimedia content.
Of course, whether or not the system has video management software is equally important, which will help users schedule, monitor, solve problems, and report in real time (interconnections with other vendors' systems). With video management software, IT departments can provide end users with the best user experience and service level requirements.
(9) Can I conduct multi-point HD conferences?
Before purchasing the system, be sure to confirm with the manufacturer whether they have built-in multi-point control units or external multi-point control units that can support high-definition video communications. Many meetings are not limited to end-to-end calls between two points.
(10) Many manufacturers claim that they have a high-definition conferencing system. How do I measure it?
When selecting a high-definition conferencing system, consider the following factors:
Fully demonstrate system functionality;
Cost-effectiveness;
True HD quality vsFCIF, 2CIF, 4CIF;
Market development and product development direction;
Products using standards and interconnection support;
Comprehensive, thoughtful product line including video systems, multi-point control units, management software, and gateways;
HD, wideband audio quality;
The stability of corporate partners and businesses.
Video conference audio interference processing
The interference that the audio signal produces in the course of transmission is various, the power interference, inter-equipment interference, light interference and so on are common.
1, power interference. Poor grounding of the power supply, poor ground contact and impedance mismatch between devices, power supply of the device without "cleaning", audio cable and AC wire laying on the same pipe, on the same ditch, or on the same bridge, will cause noise interference to the audio signal. , forming a low-frequency exchange "click" sound.
2. Interference between devices. "Howling" is caused by positive feedback between the speaker and the microphone. The main reason is that the microphone is too close to the speaker or the microphone is pointing to the speaker. The “space noise†is generated by the sound wave delay, if the microphone picks up the sound source signal and picks up the amplified sound recovery signal, or two microphones with different distance from the sound source pick up the signal of the same sound source, or a microphone picks up The signal of another microphone after being amplified will produce a corresponding path difference and cause a delay. When these signals are superimposed, some of the frequency components cancel each other, forming a "space noise."
3, light interference. If the ballast intermittently starts using the ballast, high-frequency radiation will be generated when the lamp is excited, and the microphone and its leads will be strung into the string. “出现†sound will appear; the microphone line will be too close to the lamp line. "Hush" sound. In addition, external high-frequency electromagnetic interference can also occur.
To restore the sound of videoconferencing, according to the theoretical knowledge of acoustics, according to different actual conditions, it is necessary to flexibly adjust the mixing console and equalizer to process and beautify the sound, compensate for the defects of the sound field, and create a more ideal acoustic environment; properly adjust the compression The limiter, which encounters sudden large peak signals, is not overloaded or distorted, and at the same time, the compression limiter is prevented from being compressed for a long time, so that the sound connection is smooth and mellow.
For power interference, the following methods can be used to solve: 1 increase the power filter, use the resonant circuit to filter out harmonics, "purify" the output power; 2 signal input and output lines and power lines are separated, and can not be parallel wiring, to avoid Adjacent and cross-interference, mutual induction; 3 using twisted pair power lines, so that the total flux generated by the two wires cancel each other out.
For the "howling" phenomenon, the following methods can be used to avoid the formation of a natural resonance point: 1 reduce the gain of sound reinforcement; 2 use an equalizer or an automatic feedback suppressor to reduce the amplitude of the "howling" frequency point; 3 connect a frequency shifter or adjust Phaser, use the offset frequency or phase to destroy the in-phase condition of the feedback sound and the sound source; 4 adjust the speaker layout, change the microphone direction, and the distance between the two, to avoid the formation of positive feedback.
For the “space noise†phenomenon, the following methods can be used to avoid acoustic delay: 1 Select a microphone with strong directivity; 2 Turn off the ST switch in the mixer or pull down the extra microphone putter; 3 Adjust the sound source and its amplified sound The proportion of restored sound.
For light interference, the following methods can be used to solve: 1 microphone line away from the light line; 2 microphone line through the tube shielding; 3 using a microphone with strong anti-interference ability.
To sum up, to make video conference better, we must improve the aesthetic appreciation of sound and artistic accomplishment, and conceive and creative sound reduction, in order to improve the artistic expression of sound.
Video conference HD software selection
When the user considers the requirements of the video communication system, the following 10 questions have an important influence on the user's making a correct decision.
(1) Why build a remote video conference system?
Global business is being internationalized, and people need to meet and communicate frequently. Although such expenses, such as differential fee, do not account for a large proportion of the company’s revenue, other invisible factors often have an important impact on the development of the company. Remote video systems can help companies increase production efficiency and capture the market immediately. The trend is to increase the efficiency of the team's collaborative work. These factors are usually extremely important to the company.
For enterprises, the use of video conferencing systems can immediately grasp the market and win competitive advantages. For educational institutions, students and teachers in different regions can be connected to share classroom content and learn from each other. For public agencies, they can provide immediate information, increase safety factors, and provide key communication tools for various emergencies.
(2) Why is HD resolution important in audio and video communications?
The benefits of the videoconferencing software system are that people only see and hear the participants in different areas and feel like they are in a room. At this time, people can appreciate its benefits. But now, due to limitations in processing capabilities, bandwidth, and other factors, video conferencing systems are also limited in quality. In many cases, the "true real-life experience" promised by the manufacturers cannot be fully achieved.
Compared with traditional video conferencing systems, the new high-definition video system solutions can provide 10 times more resolution than systems 10-15 years ago. The resolution of the system is now called FCIF (352 × 288 pixels), and the resolution of the HD system is 1280 × 720 pixels. In the true sense, this is the difference between seeing each other and clearly expressing the other's expression.
For example, in order to be able to make timely decisions as soon as possible, a textile mill that purchases fabrics needs to communicate with the corporate buyer on the other side of the globe. In this process, the clear details and quality of textiles can have a significant impact on the decision-making process.
High-definition, high-fidelity audio communication is also an important factor in ensuring production efficiency. Natural, full-duplex audio quality, covering the entire conference room, so that all participants clearly hear the conference, which is very important. The lack of high-definition audio quality to match video effects will not meet the end user's expectations.
(3) Will the HD system be more expensive?
Compared with the existing video conferencing system, the cost performance ratio of the HD conference system is very competitive. The new system resolution is 10 times higher than the existing system, and the price is similar to that of a general conference system. In addition, the price of high-definition displays is also rapidly falling, and the bandwidth demand for conference calls is also decreasing.
(4) How much bandwidth is needed?
This problem mainly depends on the system that the user plans to use. HD video communication requires a bandwidth of 1 Mbit/s. The previous system bandwidth was 384Kbit/s or 512Kbit/s. Moreover, some companies are using uplink 25Mbit/s (bidirectional) or 2-5Gbit/s to get high-definition video quality. In the past five years, with the popularity of bandwidth, high-quality HD video quality will be more readily available.
(5) Is the HD videoconferencing system compatible with my existing installed videoconferencing system and how can I protect my investment?
First of all, make sure that the system you are currently using is a common standard (like H.264), not some proprietary protocol.
Users all want their systems to maximize their connectivity and connect with more colleagues, suppliers, customers and other companies. One of the issues to be considered is the resolution conversion problem, which ensures that the quality of each system in each call is optimized.
In addition, in any bandwidth situation (either 384Kbit/s or 768Kbit/s), it can provide better video image quality, because the processing and coding capabilities of the new system have been greatly improved.
(6) Can I run high-definition video communications on a standard definition television device display?
In fact, users can run high-definition systems on standard-definition TV screens, but they can't reach the full HD standard of 1280x720.
(7) Can I share multimedia and PC presentations?
In many applications, the ability to share multimedia content and perform PC presentations is an important factor. Users should consider these issues when measuring the system. According to these features, users can connect the PC to the system, plug and play, and can also obtain a high-definition resolution of 16:9 format without any loss of resolution, which is called dual stream. At the same time, it is also extremely important to ensure that multimedia content is compatible with other standards. In addition, you should also consider whether you need to add an additional camera in the application, to display other locations in the room or other participants.
(8) Can the ease of use of the system be improved?
The simplicity and ease of use of the system are usually very important to the user and can greatly increase work efficiency. Interestingly, compared to SD in the 4:3 format, HD in 16:9 format may require constantly moving the camera to see all the participants. Therefore, the transparency of the technology will be very important to the user.
When measuring a system, the ease of use of the system is crucial in initiating calls, multiple calls, running cameras, and sharing multimedia content.
Of course, whether or not the system has video management software is equally important, which will help users schedule, monitor, solve problems, and report in real time (interconnections with other vendors' systems). With video management software, IT departments can provide end users with the best user experience and service level requirements.
(9) Can I conduct multi-point HD conferences?
Before purchasing the system, be sure to confirm with the manufacturer whether they have built-in multi-point control units or external multi-point control units that can support high-definition video communications. Many meetings are not limited to end-to-end calls between two points.
(10) Many manufacturers claim that they have a high-definition conferencing system. How do I measure it?
When selecting a high-definition conferencing system, consider the following factors:
Fully demonstrate system functionality;
Cost-effectiveness;
True HD quality vsFCIF, 2CIF, 4CIF;
Market development and product development direction;
Products using standards and interconnection support;
Comprehensive, thoughtful product line including video systems, multi-point control units, management software, and gateways;
HD, wideband audio quality;
The stability of corporate partners and businesses.
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