ST 2110-22: Compressed Video (JPEG XS) in the ST 2110 Hierarchy

ST 2110-22 defines the transport of lightly compressed video using the JPEG XS codec within the SMPTE ST 2110 ecosystem.

Where 2110-22 Fits in the 2110 Family

• 2110-20 = Uncompressed video (raw essence)
• 2110-22 = Lightly compressed video using JPEG XS
• 2110-30/31 = Audio
• 2110-40 = Ancillary data

2110-22 was added to give system designers a flexible middle ground between fully uncompressed (high bandwidth) and heavily compressed (high latency) video.

What a 2110 System Design Engineer Must Know

• JPEG XS is a low-latency, visually lossless compression codec (typically 5:1 to 20:1 compression ratio).
• It dramatically reduces bandwidth compared to 2110-20 (e.g., 4K 60fps can drop from ~12 Gbps uncompressed to 500–1500 Mbps).
• Latency is very low: usually under 10–20 ms end-to-end, making it suitable for live production.
• It still uses RTP multicast and the same PTP timing plane as other 2110 essences.
• Requires proper SDP signaling (different payload types and parameters than 2110-20).

Design Considerations

• Use 2110-22 when bandwidth is constrained (WAN links, shared infrastructure, or high channel count).
• Still requires excellent PTP synchronization and QoS (usually CS5/AF41).
• CS5 and AF41 QoS Markings for Media in ST 2110
• In ST 2110 systems, Quality of Service (QoS) markings are used to prioritize traffic. The two most common markings for media essence are:
  
  • CS5 (Class Selector 5) - DSCP decimal value 40
    
    High priority. Typically used for video (ST 2110-20). It receives strict or high-weighted priority in switch queues.
  
  
  • AF41 (Assured Forwarding 41) — DSCP decimal value 34
    Slightly lower priority than CS5 but still considered high priority. Commonly used for audio (ST 2110-30) and ancillary data (ST 2110-40).
• Typical QoS Hierarchy in a 2110 Network
• • CS6: PTP timing (highest priority)
  • CS5: Video (2110-20)
  • AF41: Audio (2110-30) and Ancillary (2110-40)
  Rule of Thumb for Designers:
  CS5 is the standard marking for uncompressed video traffic. AF41 is commonly used for audio and ancillary data so they remain high priority but do not compete directly with video for the top queue.
• Receivers must support JPEG XS decoding — not all 2110 devices do.
• Great for contribution, remote production, or mezzanine compression, but many core live production facilities still prefer uncompressed 2110-20 for maximum quality and lowest latency.

Summary

• Constant Bit-Rate (CBR) Focus:
  Unlike general internet streaming, which often uses Variable Bit-Rate (VBR) to optimize for visual complexity, ST 2110-22 enforces a constant bit rate. This ensures that the network fabric remains predictable and switch-friendly, avoiding the sudden "micro-bursts" of data that cause packet drops in unmanaged or strictly allocated IP production environments.


• Codecs for Production:
  The standard is designed to work with high-performance, low-latency codecs—most notably JPEG-XS. These codecs are chosen because their coding latency is extremely low (often under 1ms), allowing them to function effectively in "live" broadcast environments where traditional, high-latency codecs (like H.264/HEVC) would be unusable.


• Interoperability:
  It defines the payload format for these compressed streams so that equipment from different vendors can "speak the same language" when transmitting and receiving compressed essence.


• Synchronization:
  Because it is part of the ST 2110 suite, it is fully integrated with ST 2110-10 timing (PTP). This means that even though the video is compressed, it stays perfectly locked to the audio and ancillary data streams, maintaining lip-sync and frame accuracy across the entire production facility.