Clocking, Audio, Video, & Control

Protocols

Uses UDP ports 319 and 320 and destination IP 224.0.1.129 (multicast - registered to NIST/IEEE).

QoS

The Q-LAN sampling clock requires real-time performance (QoS Strict Priority Queuing) with packets marked DSCP 46 (Highest priority) for QoS prioritization. See the Quality of Service (QoS) topic.

Network Usage

The Q-LAN sampling clock transmits ≤100 packets per second, with ≤100 bytes per packet.

Tip: To learn about network audio channels, network audio streams, and creating efficient designs when wiring components, see Networked Audio Design.

Protocols

• Source port UDP range 6518-7030 (one port per stream) is assigned to each stream.
• Destination port UDP range 6518-7030 is used for RTCP control of each audio stream.

Note: Although not real-time critical, RTCP packets are also marked as DSCP 34 (AF41) to prevent these packets from being dropped.

QoS

Q-LAN audio streams require real-time performance (QoS Strict Priority Queuing) with packets marked DSCP 34 (Second Highest priority) for QoS prioritization. See the Quality of Service (QoS) topic.

Network Usage

• Per-channel bandwidth: 1.65 Mbps (with 16 channels of audio) to 3.31 Mbps (with 1 channel of audio) bandwidth per channel.
• Per-stream bandwidth: 3.31 Mbps (with 1 channel of audio) to 26.41 Mbps (with 16 channels of audio) per stream .
• 100 to 1100 bytes per packet with 3000 UDP packets per second, per stream. Packet size depends on channel count per stream. Audio packets contain Ethernet, IP, and UDP headers, the audio data itself, stream identifier, and time-stamp fields.
• 100 acknowledgments are sent every second and contain receiver-side stats.
• Duplicate, identical, simultaneous streams are generated on secondary Q-LAN network interface ports (e.g., LAN B) if Network Redundancy is enabled.
• The formula for determining total bandwidth per port is: Mb = ( 1.77 * total stream count ) + ( 1.54 * total channel count )

Tip: You can check your Core's bandwidth calculations using the Check Design dialog in Q-SYS Designer. Go to File > Check Design.

Latency

• System audio latency is configurable from 3.17 ms (default) to 5.17 ms end-to-end. To achieve 3.17 ms system audio latency, audio packets must always get across the network in 280 ms or less.
• Use the Network Receive Buffer property in Q-SYS Designer to increase latency if you need to accommodate a large network with a higher forwarding delay.
• Network switches and network construction must meet Q-LAN requirements – see the Network Switches & Infrastructure topic.
• Analog latency (3.17 ms) is measured using a MIC/LINE IN card and a LINE OUT or DataPort card.
• When using an AES3 card, the measurement is taken with and without Sample Rate Conversion (SRC):
  • With SRC: Total latency is 5.69 ms
  • Without SRC: Total latency is 2.81 ms

Protocols

PTZ Cameras

• Web Services Discovery: Multicast UDP 239.255.255.250 on Port 3702.
• Video stream multicasting: User-configurable between 224.0.0.0 and 239.255.255.255. Use 'Auto' mode in Q-SYS Core Manager > Network > Multicast to allow the system to supply multicast addresses.

NV-32-H Encoder

• Encoders use an RTSP server to stream video packets.
• RTSP server uses TCP and listens on ports 5540-5542 – one server for each of the three AV streams.
• Sends RTP packets (UDP) from ports 7500, 7502, 7504.
• Sends RTCP packets (UDP) from ports 7501, 7503, 7505.
• Multicasting: User-configurable between 224.0.0.0 and 239.255.255.255. Use 'Auto' mode in Q-SYS Core Manager > Network > Multicast to allow the system to supply multicast addresses.

NV-32-H Decoder

• Receives RTP packets (UDP) on ports 7516, 7518.
• Receives RTCP packets (UDP) on ports 7517, 7519.

QoS

Q-SYS video streams for both PTZ Cameras and the NV-32-H require real-time performance (QoS Strict Priority Queuing) with packets marked DSCP 26 (Third Highest priority) for QoS prioritization. See the Quality of Service (QoS) topic.

PTZ Camera Network Usage

Network usage depends on the IP stream quality, configurable in the PTZ camera Status/Control component 'Video Formats' menus. Camera streams are routed between the PTZ camera and the USB Video Bridge, which is an inventory component included with the Q-SYS Core 110f/110c, I/O-USB Bridge, and NV-32-H Network Video Endpoint.

IP Stream 1 Quality (MJPEG)

• Best – 30 Mbps (default)
• Better – 25 Mbps
• Good – 20 Mbps

IP Stream 2 Quality (H.264)

• Best – 2 Mbps (default)
• Better – 1 Mbps
• Good – 0.5 Mbps

NV-32-H Network Usage

Overview

Each Q-SYS NV-32-H Network Video Endpoint is configurable in Q-SYS Designer as either an Encoder or Decoder:

• AV streams are point-to-point, meaning they are routed directly from Encoder to Decoder without Q-SYS Core processing.
• An Encoder takes source HDMI AV signals and places them on the network in streams. Encoders can process a single stream up to 4K60 or three simultaneous streams up to 1080p60 each.
• A Decoder processes incoming network HDMI signals and sends them to a display. Decoders can process a single stream up to 4K60 or two simultaneous streams up to 1080p60 each.
• Each stream can be either unicast (one Encoder to one Decoder) or multicast (one Encoder to two or more Decoders), determined by schematic wiring in Q-SYS Designer.
• Each Encoder consumes up to 800 Mbps of network bandwidth, plus overhead, depending on its bitrate setting.

Encoder Bitrate

Network usage is determined by the Encoder's video bitrate setting. Use the Bitrate (Mbps) control in the Encoder's HDMI I/O component control panel to set the maximum average network video bitrate for that Encoder. The value is configurable from 50 to 800 Mbps, which is shared across all Encoder AV streams (unicast or multicast) from that Encoder. You configure this value for each Encoder in your design.

Lower bitrates consume less network bandwidth, but at the expense of compromised video quality during fast motion and transitions. For acceptable video quality:

• 4K60 stream – set the bitrate to at least 650 Mbps.
• 1080p streams – set to the bitrate so that each stream can use at least 250 Mbps.

Note: The Bitrate value is shared across all AV streams. For example, if you set the Bitrate to 600, the first AV stream can use a maximum of 600 Mbps. If a second stream becomes active, both streams can use 300 Mbps. If a third stream becomes active, each stream can use 200 Mbps.

Switch Requirements for AV Streaming

For acceptable video streaming performance, observe these requirements:

• Due to the bandwidth intensity inherent to network video streaming, network switches must strictly meet Q-LAN switch requirements, including non-blocking wire-speed Gigabit Ethernet. See the Network Switches & Infrastructure topic.
• It is critical to have proper QoS and multicast configuration (IGMP snooping and/or PIM-SM). See the Quality of Service (QoS) and Multicast Traffic topics.
• You must disable jumbo frames or jumbo packets to avoid impacts to latency, jitter, and packet loss performance on the network. For more information, see the Network Switches & Infrastructure topic.

Inter-Switch Link Requirements

As long as each switch supports Q-LAN requirements, traffic between ports on the same switch is not a concern, as each port must support non-blocking wire-speed Gigabit Ethernet. However, connections between network switches (inter-switch links) must support the aggregate consumed bandwidth of all switch ports, plus overhead. Do not exceed 80% network backbone usage without performing a proof of concept to establish if the network can deliver acceptable performance under load.

For example:

• If a 10-port 1 Gigabit switch has connections to 10 NV-32-H Encoders, each streaming 4K60 video using the maximum bitrate of 800 Mbps, then: 10 x .800 = 8 Gbps must successfully pass from this switch to other network switches with connections to NV-32-H Decoders. Assuming a 10 GbE network backbone with a maximum recommended network usage of 80%, this configuration provides adequate bandwidth.
• If a 48-port 1 Gigabit switch has connections to 48 NV-32-H Encoders, each streaming three 1080p AV streams for a combined bitrate of 750 Mbps, then: 48 x .750 = 36 Gbps must successfully pass from this switch to other network switches with connections to NV-32-H Decoders. In this case, a 40 GbE backbone may not be sufficient when allowing for 80% usage.

Protocols

• Control communications between Q-SYS Designer and the Core are via self-signed, encrypted HTTPS (TCP port 443).
• Control communications between Q-SYS UCI Viewers, Q-SYS touch screens, and the Core are via HTTPS (TCP port 443).
• Q-SYS Discovery Protocol (QDP): Multicast UDP 224.0.23.175 on Ports 2467-2470 and Unicast on Port 6504
• Q-SYS Control Binary Secure (QCBS): TCP Port 1704
• External Control (ASCII) is on TCP port 1702
• Remote Control (JSONRPC) is on TCP port 1710

QoS

Q-SYS Control traffic falls under the Lowest priority (DSCP 0). See the Quality of Service (QoS) topic.

Network Usage

Q-SYS Control traffic uses 10 Mbps or less. Non-redundant systems typically use less than 2 Mbps. Actual bandwidth depends on the number of connections to User Control Interfaces (UCIs), redundant Q-SYS Core processors, and connections to third-party control systems.

Note: QDP transmissions are approximately once per second per Q-SYS device.