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Technical Reference · Authorised Magewell Reseller UK

NDI · SRT · RTMP Bandwidth
Requirements — Complete Reference 2026

The definitive bandwidth and bitrate reference for IP video professionals. Full NDI, NDI HX3, NDI HX2, NDI HX, SRT (H.264 & H.265), RTMP, HLS and RTSP — every protocol, every resolution, every frame rate. Used by AV integrators, broadcast engineers and system designers worldwide.

Published: June 2026 Source: iView Data Ltd — Authorised UK Magewell Reseller Audience: AV Integrators · Broadcast Engineers · IT Managers · Content Creators
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01 Protocol Overview #protocols

Each protocol was designed for a different environment and bandwidth constraint. Understanding where each operates correctly prevents the most common bandwidth planning mistakes.

Full NDI LAN only NDI HX3 LAN / WAN NDI HX2 LAN / WAN NDI HX LAN / WAN SRT LAN / WAN / 4G RTMP WAN delivery HLS CDN / browser RTSP LAN monitoring
NDI

NDI — Network Device Interface

  • Developed by NewTek — standard for professional LAN video production
  • Full NDI: SpeedHQ intra-frame codec, 75–600 Mbps, lowest latency
  • NDI HX3: H.265 up to 62 Mbps — approaches Full NDI quality
  • NDI HX2: H.265 8–20 Mbps — monitoring and preview
  • NDI HX: H.264 8–18 Mbps — widest device compatibility
  • Requires Gigabit managed switch for Full NDI — never use over Wi-Fi
SRT

SRT — Secure Reliable Transport

  • Open-source protocol by Haivision — designed for unreliable networks
  • Built-in ARQ packet retransmission — recovers from 5–10% packet loss
  • AES-128/256 encryption — mandatory for public internet delivery
  • Caller and Listener modes — handles NAT traversal
  • Add 25–30% bandwidth overhead above encoded bitrate
  • Ideal for 4G/LTE, satellite, VPN and WAN contribution links
RTMP

RTMP — Real-Time Messaging Protocol

  • Adobe protocol from 2002 — ubiquitous for platform delivery
  • No built-in error recovery — packet loss causes visible corruption
  • H.264 only on most platforms — H.265 not universally supported
  • Each platform sets its own maximum bitrate ceiling
  • Use for final delivery to YouTube, Facebook, Twitch, TikTok
  • Not recommended for contribution links — use SRT instead

02 NDI Bandwidth Requirements #ndi

Full NDI uses SpeedHQ intra-frame compression — every frame is independently compressed, giving the lowest latency and highest quality but the highest bandwidth requirement. NDI HX variants use inter-frame H.264/H.265 compression, dramatically reducing bandwidth at the cost of slightly higher latency and quality.

Resolution Frame rate Colour space Full NDI NDI HX3 (H.265) NDI HX2 (H.265) NDI HX (H.264)
720p 30 fps 4:2:2 8-bit 30–50 Mbps 6–12 Mbps 4–8 Mbps 4–7 Mbps
720p 60 fps 4:2:2 8-bit 40–75 Mbps 10–20 Mbps 6–10 Mbps 5–8 Mbps
1080p 30 fps 4:2:2 8-bit 75–100 Mbps 15–30 Mbps 8–15 Mbps 8–12 Mbps
1080p 60 fps 4:2:2 8-bit 125–200 Mbps 30–50 Mbps 12–20 Mbps 12–18 Mbps
1080p 60 fps 4:4:4 10-bit 200–280 Mbps 40–60 Mbps N/A N/A
4K UHD 30 fps 4:2:2 8-bit 250–400 Mbps 40–62 Mbps 20–35 Mbps Not supported
4K UHD 60 fps 4:2:2 8-bit 400–600 Mbps 50–62 Mbps Not supported Not supported
4K DCI 30 fps 4:2:2 10-bit 500–700 Mbps 50–62 Mbps Not supported Not supported
Critical: Full NDI at 1080p60 requires 125–200 Mbps sustained bandwidth. A standard Gigabit switch (1000 Mbps) supports a maximum of 5–6 simultaneous Full NDI 1080p60 streams before saturation. Plan your network switch capacity accordingly — use a managed switch with QoS enabled.
Bandwidth tip: NDI HX3 at 62 Mbps maximum delivers visually near-indistinguishable quality from Full NDI for most production scenarios, at one-third of the bandwidth. Use Full NDI only where the lowest possible latency is critical — typically for in-ear monitoring, tally systems, or live intercom feeds.

03 SRT Bandwidth Requirements #srt

SRT bandwidth is the sum of your encoded video bitrate plus an overhead allowance for packet retransmission. The recommended overhead is 25% for typical internet connections with up to 5% packet loss, and 40% for cellular or satellite links. Always provision your bandwidth for the worst expected network conditions, not the average.

Resolution Frame rate H.264 encoded bitrate H.265 encoded bitrate SRT overhead (25%) Total bandwidth — H.265 Upload speed needed
480p 30 fps 1.5–2 Mbps 0.75–1 Mbps +25% ~1.3 Mbps 2+ Mbps upload
720p 30 fps 2.5–4 Mbps 1.5–2.5 Mbps +25% ~3 Mbps 4+ Mbps upload
720p 60 fps 3.5–5 Mbps 2–3 Mbps +25% ~3.8 Mbps 5+ Mbps upload
1080p 30 fps 4–6 Mbps 2–4 Mbps +25% ~5 Mbps 7+ Mbps upload
1080p 60 fps 6–9 Mbps 3–5 Mbps +25% ~6.3 Mbps 9+ Mbps upload
4K UHD 30 fps 15–25 Mbps 8–15 Mbps +25% ~19 Mbps 25+ Mbps upload
4K UHD 60 fps 25–40 Mbps 15–25 Mbps +25% ~31 Mbps 42+ Mbps upload
4G / LTE Any Keep encoded bitrate under 2 Mbps +40% ~2.8 Mbps 5+ Mbps cellular
SRT bandwidth calculation formulas
Standard internet (≤5% packet loss)
Required BW = Encoded Bitrate × 1.25
Example: 6 Mbps H.265 → 7.5 Mbps required
4G / cellular / satellite (≤10% loss)
Required BW = Encoded Bitrate × 1.40
Example: 2 Mbps H.265 → 2.8 Mbps required
SRT latency setting (rule of thumb)
Latency = RTT × 4
Example: 50ms RTT → set 200ms SRT latency
Sustained upload available
Usable BW = Headline Speed × 0.70
Example: 20 Mbps headline → 14 Mbps usable

04 RTMP Platform Bitrate Requirements #rtmp

Each streaming platform sets its own bitrate limits. Exceeding the maximum causes the platform to re-encode your stream, reducing quality. Below the minimum causes heavy compression artefacts. All figures are H.264 — H.265/HEVC is not widely supported for RTMP ingestion on consumer platforms as of 2026.

Platform Resolution FPS Min bitrate Recommended Maximum Upload speed needed Audio bitrate
YouTube 4K / 2160p 60 20 Mbps 30–51 Mbps 51 Mbps 65+ Mbps 128–320 Kbps AAC
YouTube 4K / 2160p 30 10 Mbps 15–20 Mbps 51 Mbps 25+ Mbps 128–320 Kbps AAC
YouTube 1080p 60 3 Mbps 4.5–9 Mbps 9 Mbps 12+ Mbps 128 Kbps AAC
YouTube 1080p 30 2 Mbps 3–4.5 Mbps 6 Mbps 8+ Mbps 128 Kbps AAC
YouTube 720p 60 1.5 Mbps 2.25–3 Mbps 4 Mbps 5+ Mbps 128 Kbps AAC
Facebook 1080p 30 1 Mbps 3–4 Mbps 4 Mbps 6+ Mbps 128 Kbps AAC
Facebook 720p 30 0.5 Mbps 1.5–2.5 Mbps 4 Mbps 4+ Mbps 128 Kbps AAC
Twitch 1080p 60 3 Mbps 4.5–6 Mbps 6 Mbps 9+ Mbps 160 Kbps AAC
Twitch 720p 60 2 Mbps 3–4.5 Mbps 6 Mbps 6+ Mbps 160 Kbps AAC
TikTok Live 1080p 30 2 Mbps 2–4 Mbps 4 Mbps 6+ Mbps 128 Kbps AAC
LinkedIn Live 1080p 30 0.5 Mbps 1–3 Mbps 3.5 Mbps 5+ Mbps 96 Kbps AAC
Custom RTMP Any Any Varies Varies No limit BW = bitrate × 1.15 128–320 Kbps AAC
Upload speed rule: Your sustained upload speed must be at least 1.5× your stream bitrate — not equal to it. ISP headline speeds are burst speeds. At 6 Mbps RTMP, you need at least 9 Mbps sustained upload. Test your upload at fast.com or speedtest.net before your event, not just at home setup time.

05 HLS & RTSP Reference #hls-rtsp

HLS is used for viewer-side delivery via CDN and browsers. RTSP is used for pull-based LAN monitoring, NVR systems and IPTV. Neither is suitable as a contribution protocol — use SRT for contribution and NDI for LAN production.

Protocol Use case Resolution Bitrate per stream Viewer-side latency Key characteristics
HLS CDN / web delivery 1080p 30fps 3–6 Mbps 6–30 seconds Segment-based HTTP. Universal browser support. ABR ladder for adaptive quality.
LL-HLS Low-latency web delivery 1080p 30fps 3–6 Mbps 2–4 seconds Apple Low-Latency HLS. Reduces segment size. Not all CDNs support it.
HLS ABR ladder Adaptive viewer delivery 360p–1080p60 0.4–9 Mbps per rung 6–30 seconds Typical rungs: 400K/360p, 800K/480p, 2M/720p, 4M/1080p, 9M/1080p60
RTSP LAN monitoring / IPTV 1080p 30fps 2–6 Mbps 1–3 seconds Pull-based — receiver requests stream. VLC, Plex, NVR systems. Not NAT-friendly.
RTSP IP camera / NVR 1080p 25fps 1–4 Mbps 1–3 seconds Standard for network cameras, video management and security systems.

06 Protocol Selection Guide #selection

The correct protocol depends on your network environment, latency requirement, and delivery destination — not personal preference. Use this guide as a starting point for system design decisions.

USE

Full NDI when…

  • All devices are on a Gigabit managed LAN
  • Lowest possible latency is critical (tally, IEM, intercom)
  • Source is a Pro Convert encoder on the same network
  • Using vMix, OBS, TriCaster or NDI-native software
USE

NDI HX3 when…

  • LAN bandwidth is constrained (Wi-Fi, 100 Mbps switches)
  • Multiple simultaneous NDI streams on one switch
  • 4K sources over a network not provisioned for Full NDI
  • PTZ cameras with NDI HX3 output (most modern PTZ)
USE

SRT when…

  • Streaming over the public internet (any distance)
  • 4G, LTE, satellite or bonded cellular links
  • Encryption is required (AES-256)
  • Remote contribution from field locations
  • Replacing RTMP for broadcast contribution
USE

RTMP when…

  • Final delivery to YouTube, Facebook, Twitch, TikTok
  • Stable broadband connection at the delivery point
  • Platform requires RTMP ingest specifically
  • Using a cloud multistreaming relay service
USE

HLS when…

  • Delivering to browser-based viewers via CDN
  • Adaptive bitrate for viewers on variable connections
  • VOD or time-shifted playback
  • IPTV distribution over managed networks
USE

RTSP when…

  • Monitoring encoder output on a local LAN
  • Integrating with NVR or VMS systems
  • IPTV set-top box distribution on a managed LAN
  • VLC or media player monitoring at low latency

07 Common Bandwidth Planning Mistakes #mistakes

These are the most frequently encountered bandwidth planning errors in IP video deployments. Each one causes problems that are difficult to diagnose after installation.

Running Full NDI over Wi-Fi

  • Full NDI at 1080p60 requires 125–200 Mbps sustained
  • Wi-Fi 5 (802.11ac) theoretical max is ~867 Mbps — real-world is 200–400 Mbps shared across all devices
  • A single Full NDI stream will saturate most Wi-Fi environments
  • Solution: use NDI HX3 (max 62 Mbps) over Wi-Fi, or run Ethernet

Ignoring SRT overhead

  • SRT requires 25–40% bandwidth above your encoded bitrate
  • A 6 Mbps H.265 stream needs ~7.5–8.5 Mbps of available bandwidth
  • Forgetting overhead causes stream drops under load — not at idle
  • Always test at sustained load, not during quiet periods

Using headline upload speed as your limit

  • ISP headline speeds are burst speeds, not sustained
  • Sustained upload is typically 60–70% of headline speed
  • Other devices on the same connection reduce this further
  • Use fast.com under load conditions to measure real sustained upload

Exceeding RTMP platform maximums

  • Bitrate above the platform maximum is silently re-encoded
  • You use more upload bandwidth but viewers see no improvement
  • Facebook cap is 4 Mbps — sending 8 Mbps wastes half your upload
  • Always match your encoder output to the platform's stated maximum

Not accounting for multiple simultaneous streams

  • Each simultaneous RTMP destination multiplies bandwidth use
  • 3 × 6 Mbps RTMP streams = 18 Mbps upload minimum (×1.5 = 27 Mbps needed)
  • Hardware encoders with 6 destinations require significant upload headroom
  • Plan total bandwidth for all destinations combined, not per-stream

Underpowered network switches for NDI

  • Unmanaged switches have no QoS — NDI traffic competes equally with everything else
  • A 100 Mbps switch cannot carry even one Full NDI 1080p60 stream
  • Use Gigabit managed switches with IGMP snooping enabled for NDI
  • 10GbE core switches recommended for large NDI deployments

08 Cite This Reference #cite

This data is freely available for use in articles, guides, system designs and educational materials. Please attribute iView Data as the source using one of the formats below.

Citation formats
APA
iView Data Ltd. (2026). NDI vs SRT vs RTMP — Complete Bandwidth Requirements Reference. Retrieved from https://iviewdata.com/ndi-srt-rtmp-bandwidth-requirements/
Chicago / MLA
iView Data Ltd. "NDI vs SRT vs RTMP — Complete Bandwidth Requirements Reference." iviewdata.com, June 2026. https://iviewdata.com/ndi-srt-rtmp-bandwidth-requirements/
Inline / journalist reference
According to bandwidth reference data published by iView Data (iviewdata.com), Full NDI at 1080p60 requires 125–200 Mbps of sustained LAN bandwidth…
HTML link
<a href="https://iviewdata.com/ndi-srt-rtmp-bandwidth-requirements/">NDI SRT RTMP Bandwidth Reference — iView Data</a>

Data is reviewed and updated periodically. Platform bitrate figures reflect published guidelines as of June 2026. NDI figures reflect NewTek/Vizrt specification documentation. SRT figures reflect the SRT Alliance specification. Please link to this page rather than copying the data, so your readers always see the most current version.

¹ Full NDI bandwidth varies significantly with scene complexity and motion — high-motion content (sport, concerts) requires the upper end of the stated range. Static content (presentations, talking heads) sits at the lower end.

² SRT overhead of 25% assumes network conditions with up to 5% packet loss. Increase to 40% overhead for 4G/LTE, satellite, or networks with higher observed packet loss.

³ RTMP platform bitrate figures are based on each platform's published streaming guidelines as of June 2026 and are subject to change by the platform operator. Always verify against current platform documentation before a major event.

⁴ Upload speed recommendations assume the stream is the primary consumer of upload capacity on that connection. Reduce available bandwidth by 30% if other upload traffic (video calls, cloud backup, other streams) is running simultaneously.

⁵ NDI is a trademark of NewTek Inc / Vizrt Group. SRT is an open-source protocol maintained by the SRT Alliance. RTMP is a trademark of Adobe Inc. iView Data Ltd has no affiliation with these organisations.

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