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A new generation of connectivity for ProAV — AV over IP
It does not take long for everyone to hear about this new buzz that comes with AV over IP (AVoIP). A basic look at the technology and features of this new technology will be covered in this paper.
A flexible I/O system:
A traditional HDMI or HDBaseT AV switcher does not support bi-directional data streaming. The RJ45 ports on an IP switch can be either a transmitter or receiver at the same time. The number of inputs and outputs of an AV switch is always fixed, and the direction of the data flow is always the same. These configurations are usually a factor of two: 2×2, 4×4, 8×4, 8×8, 16×16, 24×24, etc. The configuration of such a switch and the direction of the data flow cannot be changed once it is installed.
The configuration limit here is only the total number of these ports, but each port can be a transmitter or receiver of data if 48 Port IP switch is used for AV installation. Therefore, 48 ports can be used to create a matrix of 1×47 or 47×1 with any other matrix ratio XxY in between with the restriction that X+Y cannot exceed 48.
The use of each port as transmitter or receiver only controlled by the number of Video ENC or DEC units connected to the IP switch. After installation, the ratio can be changed by adding or removing Video ENC or DEC units to any of the ports. Due to the fact that none of the ports are designated as transmitters or receivers, any of the ENC and DEC may be added or removed to any of the ports. A traditional HDMI, DVI, VGA or HDBaseT AV switch can’t provide that kind of flexibility.
The use of each port as transmitter or receiver only controlled by the number of Video ENC or DEC units connected to the IP switch. After installation, the ratio can be changed by adding or removing Video ENC or DEC units to any of the ports. Due to the fact that none of the ports are designated as transmitters or receivers, any of the ENC and DEC may be added or removed to any of the ports. A traditional HDMI, DVI, VGA or HDBaseT AV switch can’t provide that kind of flexibility.
Nowadays, IP switchers are a universal data connection device that allows audio, video, all types of data, control, and etc. It is a very flexible system that allows connectivity regardless of data type. In the AVOIP world, we take full advantage of that flexibility. As part of the transmission or reception of the data stream, AVOIP ENC can include RS232, IR, USB, audio, and video.
Flexibility with data types:
The data types can also keep their own origins and destinations controlled only by IP addresses, which is another remarkable feature. Similarly, downstream video data packets travel from the HDMI input to the HDMI output of Encoder #A, while upstream USB data travels between the USB inputs of Decoder #C and the USB outputs of Encoder #D. RS232 data may also travel downstream from Encoder #E to Decoder #F.
Control data (RS232, IR) goes between any ports as long as each port has its own IP address, and reflects the overall topology of the IP switch. Video and audio data are more rigid and always flow from the encoder to the decoder. More cost-effective IC’s force us to use dedicated encoders and decoders for video and audio. Nevertheless, in the ProAV world, this limitation does not apply as video and audio equipment is always divided into Sources and Displays. There is always a need for an encoder at the Source, and a decoder at the Display.
Control data (RS232, IR) goes between any ports as long as each port has its own IP address, and reflects the overall topology of the IP switch. Video and audio data are more rigid and always flow from the encoder to the decoder. More cost-effective IC’s force us to use dedicated encoders and decoders for video and audio. Nevertheless, in the ProAV world, this limitation does not apply as video and audio equipment is always divided into Sources and Displays. There is always a need for an encoder at the Source, and a decoder at the Display.
TControl System Master Controller can be connected to ANY (Decoder or Encoder) RS232/IR port on the system and retrieved from any other port on the network as its circuitry does not perform dedicated encoding or decoding functions. This is also a remarkable level of flexibility that would not be possible with a traditional HDMI or HDBaseT AV switch.
The Power Over Ethernet standard
Taking full advantage of POE is a feature of AVOIP which is a fully standard IP interconnection technology. AVOIP is a 48V technology with a variety of commoditized technologies available at all levels of product manufacture, including modules, integrated circuits, IP switchers, injectors, separators, etc. An average AVOIP encoder or decoder consumes approximately 10 Watts of power, so a 48 port IP switch must provide 480 Watts of POE power on each port. In particular, this is useful for DEC units, which are usually located between the TV monitor and the wall, with limited access to power. ENCs are sometimes installed within the conference room and can also be accessed by POE switches. This is not possible in pure HDMI systems, but is becoming increasingly popular with HDBaseT systems.
As compared to HDMI or HDBaseT, AVOIP has one disadvantage – the video component must always be compressed. The reason for this is simple: the most commonly used specification of IP switchers is 1 Gbps per I/O port. The following data rate requirements apply to two of the most popular uncompressed video formats in the best video related configurations:
• 2.5 Gbps is required for 1080p, 60 frames per second, 4:2:2, 10 bits per color.
• 10 Gbps is required for 4K UHD, 60 frames per second, 4:2:2, and 10 bits per color.
• 2.5 Gbps is required for 1080p, 60 frames per second, 4:2:2, 10 bits per color.
• 10 Gbps is required for 4K UHD, 60 frames per second, 4:2:2, and 10 bits per color.
Compression
IP switchers with 10Gbps per port are available, but they are much more expensive and significantly complicate the construction of large matrix systems.
Currently, there are two basic compression systems used in AVOIP systems. A description of the basic technology involved in each system follows.
: http://www.keydigital.com/KnowledgeCenter_H264_MPEG_in_ProAV.html
Currently, there are two basic compression systems used in AVOIP systems. A description of the basic technology involved in each system follows.
: http://www.keydigital.com/KnowledgeCenter_H264_MPEG_in_ProAV.html
AVOIP compression technologies can be divided into two basic categories:
Incoming video can be compressed by 180 percent or better with this H.264/265 system. As a result, 1080p video can be compressed to 16 Mbps or less. In contrast, 4K video can be compressed to 60 Mbps or less with this system. In addition to saving money, it will enable the construction of very large matrix systems, such as those measuring 256×256 and larger. In order to achieve this high rate of compression, information must be spread over 15 frames, and the decoded video may be 200ms to 500ms behind the original video time base. In some applications, video that must be shown both as original and as compressed video will result in out-of-synchrony video. For example, a large concert or lecture stage with live performance (no delay) and video monitors that extend far back in the hall may be an example. In the case of this system using H.264/265, the extended video monitors will be 0.5 seconds behind real time, and this delay is very noticeable.
Medium Compression JPEG2000 or variant thereof. In this system, video can be compressed by a factor of 10 or more. Thus, 1080p video may be compressed to 180 Mbps or less, and 4K video may be compressed to 900 Mbps or less. These are reasonable rates for current IP switches — below 1 Gbps per port. This will allow for the creation of matrix systems of reasonable size, such as 40×96 or larger. As all compression processing is accomplished within one video frame timing, the overall delay will not exceed 17ms, which is way below the human sensitivity to video and audio delays. It is possible to display processed and original video and audio content in the same room without causing any difficulties to the viewer. In addition to delay processing being limited to one frame, additional image processing features including Video Wall are also available.
AV over IP video wall example (Key Digital® Enterprise AVTM over IP System.
48x48 matrix
IP switch expandability
It's easy to get used to good things... IP switches come in one unit switchers up to 48 ports. What if you need more than 48 encoders and decoders? It is possible to speed up IP switchers so they can handle larger configurations. The key point here is the transfer rate of data between switchers. Let's say we need a 48x48 matrix.
It's easy to get used to good things... IP switches come in one unit switchers up to 48 ports. What if you need more than 48 encoders and decoders? It is possible to speed up IP switchers so they can handle larger configurations. The key point here is the transfer rate of data between switchers. Let's say we need a 48x48 matrix.
In this example, all Video Encoders are connected to switch B and all Video Decoders are connected to switch A, so all data flows between switchers in this example is from switch B to switch A. 900Mbps x 48 = 43.2 Gbps should be comfortable if all video sources are 4K UHD and the compression system is JPEG2000.
It won’t be available on all switchers. The SFP extensions are usually around 2 Gbps or 10 Gbps. Also, most of the time, there are just two of them available. So if you have four 10 Gbps SFPs, 40 Gbps can be used. That’s not enough for this particular application. Your matrix can only be 40×48 if you lower the number of encoders to 40.
If you choose H.264/265 compression and 1080p video resolution, this system requires only 16 Mbps x 48 = 0.770 Gbps. One 1 Gbps SFP port can easily extend it to a large system. The downside of H.264/265 is that it has a high latency and a limited set of video processing tools. Integrators need to know a few things when designing big AVOIP systems:
• What’s the system size?
• Does the installation feature processed and unprocessed video and audio (latency problem)?
• Is the video resolution required? For instance, if your 48×48 system uses JPEG2000 and 1080p video resolution, the bandwidth required is 8.7 Gbps, which is manageable by many different switchers.
It won’t be available on all switchers. The SFP extensions are usually around 2 Gbps or 10 Gbps. Also, most of the time, there are just two of them available. So if you have four 10 Gbps SFPs, 40 Gbps can be used. That’s not enough for this particular application. Your matrix can only be 40×48 if you lower the number of encoders to 40.
If you choose H.264/265 compression and 1080p video resolution, this system requires only 16 Mbps x 48 = 0.770 Gbps. One 1 Gbps SFP port can easily extend it to a large system. The downside of H.264/265 is that it has a high latency and a limited set of video processing tools. Integrators need to know a few things when designing big AVOIP systems:
• What’s the system size?
• Does the installation feature processed and unprocessed video and audio (latency problem)?
• Is the video resolution required? For instance, if your 48×48 system uses JPEG2000 and 1080p video resolution, the bandwidth required is 8.7 Gbps, which is manageable by many different switchers.
An example of an expansion for a 48x96 AVOIP system is as follows.
Usually IT/IP cables aren’t to exceed 330 feet from the source or sink to the switch and from the switch. That’s comparable to HDBaseT cable length capabilities. A few standard IT technologies are available if you need to go over 330 feet: fiber or coaxial. If you use an IP switch as a repeater between ENC and DEC, you can double the length to 660 feet.
The length of the connection
An example of an AVOIP system used for extension.
Based on articles By Mike Tsinberg