Monitoring Wall: How to Choose the Whole Package Configuration of Decoder vs Splicing Processor-Qunmao

First, give a judgment: the decoder tube "turns the network video stream into a picture" and the splicing processor tube "arranges the picture on the whole LCD wall". The most common rework of monitoring wall projects is to mix the two, or use HDMI matrix as control. However, before going "decoder independent control" by default, we should first see a trend:Decoding and Spelling are merging into one box.For projects with pure video domain and no multi-domain isolation requirements, a decoding matrix with splicing control capability can complete decoding, segmentation, roaming, splicing and plan scheduling, saving the cost of independent splicing controller, cabinet space and an operation and maintenance interface. Hierarchical deployment is still required for multi-domain isolated, complex multi-source wall scenarios, but "must be hierarchical" is no longer the default answer for all projects. This article disassembled the role division of labor, three types of scenario configuration, selection calculation and interface locking items.

1. split the role first: they are not the same kind of equipment at all

1.1 Network Video Decoder/Decoding Matrix

• Input:IPC, NVR, GB/T 28181 platform, ONVIF/RTSP stream
• Done things:Received network compression stream → hardware solution H.264/H.265 → HDMI/DP baseband signal
• Core indicators:Number of real solutions (based on 1080P equivalent), encoding compatibility, protocol compatibility, number of output ports, delay
• Typical output:Single port 4/9/16 split, or independent HDMI per channel
• Positioning:"Monitor the upper wall entrance"

1.2 Splice Processor/Splice Controller (Splice Controller)

• Input:HDMI / DP / DVI/VGA/Decoder HDMI/Computer Source/Video Conference Terminal
• Done things:M×N whole wall splicing, arbitrary window opening, roaming, zooming, layer overlay, scene plan, cross-screen
• Core indicators:Number of output blocks, single-port resolution, number of window layers, synchronization accuracy, number of scenes, redundant architecture
• Positioning:"whole wall picture layout engine"

1.3 Common Confusions

• HDMI Matrix:Only the local HDMI signal is cut, and the network code stream is not decoded → IPC cannot be connected
• NVR output:General 1~4 HDMI, suitable for small walls, can not support 3 × 4 flexible layout
• decoding spell control one machine:Put the above two pieces together in one chassis, suitable for pure video wall and small and medium-sized projects, not suitable for multi-domain isolation.
• Distributed nodes:Decoding/acquisition network control, suitable for large command centers and sub-domain scenarios

2. standard layered architecture (recommended for tender)

Division of labor:

• Decoder: only responsible for "solution", not for whole wall typesetting
• Spelling control: only responsible for "arranging" and not for decoding IPC code stream (unless it is an all-in-one machine)
• LCD screen: only responsible for "show", itself without network decoding capability

3. when the decoder is sufficient and when must spell control be added

Class A: pure monitoring, small wall, grid display → decoder or all-in-one machine

Applicable:Park/factory/residential area/warehouse 2 × 2, 2 × 3, 3 × 3 walls; The whole wall is cut into 4/9/16/36 squares without roaming across screens. No GIS, no computer desktop, no consultation terminal; Tight budget, short construction period and few operation and maintenance personnel.

Configuration:Network decoder (with basic segmentation/round trip/OSD); Directly connected to LCD splicing screen; Or decoding and control all-in-one machine.

Boundary:Single screen segmentation is enough, and it is not required to "drag all the way to any position on the whole wall"; The alarm pop-up window is only required to use the built-in rules of the decoder.

Class B1: multi-source same wall, no domain isolation → all-in-one machine plus HDMI acquisition input

Applicable:District and county traffic police, emergency duty hall, park operation center. There is a video GIS consultation on the wall, but the network is not classified and does not require physical isolation.

Configuration:Decoding matrix with spell control capability, reserved HDMI input port for GIS and commercial source. Save independent control, save a cabinet unit, save an operation and maintenance interface. Before selection, confirm that the number of HDMI input ports of the all-in-one machine is sufficient to connect non-video sources.

Why it works:The video domain and the service source share a single chassis, which is acceptable when there is no isolation requirement. The price is redundancy-a single chassis fails and the whole wall is paralyzed, and the spare machine or dual power supply model needs to be retained.

Class B2: Multi-domain Isolation, Complex Multi-source Same Wall → Decoder Plus Independent Spelling Control

Applicable:Public security sub-center, civil air defense, national movement, armed police. There is a subtitle bar for monitoring video GIS situation command desktop video conference on the wall. Require cross-screen large picture, single-screen top, window drag and drop, scene one-click cut; Multi-domain physical isolation (video domain/command domain/conference domain).

Configuration:Network decoder for video domain (16/32 channel level is selected according to the number of concurrent real solutions); The computer/business domain uses DP/HDMI acquisition node to control the whole wall. FPGA controller or distributed display control is used for the whole wall. The decoder sends out HDMI input, and the control is sent out to LCD wall.

Why can't the province spell control:The decoder will reach the upper limit for "roaming with windows open all over the wall". GIS base map and command desktop are not IPC streams, and the decoder cannot solve them. Multi-domain isolation requires "video decoding" and "whole wall composition" to be audited separately.

Class C: multi-wall cluster/hierarchical command → distributed display control

Applicable:Provincial-city-county level 3, main wall side wall conference room; Signals should be dispatched across rooms, seats KVM, offline self-sustaining; letter creation/localization, equal protection/confidentiality evaluation.

Configuration:Front-end decoding node (solution IPC) acquisition node (solution computer source); Independent display and control network; Output-end screen node or spell control box; Control layer visualization platform scene engine.

4. selection calculation: don't buy decoder according to the total number of cameras

4.1 decoder path number algorithm

Concurrent wall equivalent = Σ (number of resident paths × resolution factor) conversion and amplification of single-screen main code stream

Reference Coefficients (Base: 1080P@30fps = 1.0)

• 720P ≈ 0.44
• 1080P = 1.0
• 4MP ≈ 1.5
• 4K ≈ 4.0
• Sub-stream for sub-windows: Equivalent factor ≈ 0.2~0.44

Example:The video wall permanently displays 8 channels of 1080P, 4 channels of 4K, plus 18 cycling 720P sub-windows. Converted to 1080P equivalent: 8 + 16 + 8 ≈ 32ch 1080P. This calls for one 32‑channel decoding unit or two cascaded 16‑channel units. Decoder capacity should **not** be selected simply based on the total number of cameras (e.g. 500 cameras does not require a 500‑channel decoder).

4.2 Splicing Controller Sizing Formula

• Output Ports ≥ Number of Video Wall Panels (Direct Drive Mode)
• Or: Splicing controller input ports ≥ Decoder output ports + PC signal sources
• Overlay layers are defined by use case: 1–2 layers suffice for monitoring video walls; command walls require 3–4 layers (video, GIS, subtitles, alarm pop‑ups).
• Scenario Presets: Separate storage for Daily, On‑Duty, Emergency, Conference and Drill modes

5. Protocols & Key Specifications (Suitable for Bidding Documents)

Decoder

• Encoding: H.264 / H.265 / Smart264 / Smart265 / MJPEG
• Protocols: ONVIF, RTSP, GB/T 28181-2022, SDK for Major NVR & Platforms
• Decoding Capacity: 32ch 1080P@30fps / 8ch 4K@30fps
• Outputs: HDMI 2.0, Single Port 4K@30Hz, Independent Multi‑Port Outputs
• Functions: Image Split, Cyclic Patrol, OSD, Alarm Pop‑ups, Offline State Retention, Dual Ethernet Ports, 7×24 Operation
• 32‑channel Cascaded Unit: Dual Power Supply, Modular Slots, Log Auditing

Video wall processor

• Inputs: HDMI, DP, DVI, VGA, 3G‑SDI + IP Decoding (All‑in‑One Unit)
• Output: Arbitrary M×N Video Wall, Single‑Screen Multi‑Window, Cross‑Screen Roaming, Layer Overlay
• Synchronization: Frame Synchronization, Tear‑Free, Seamless Switching
• Control: Web, Client, RS232, SDK, Central Control Integration
• Redundancy: dual master hot standby, power-down memory, offline self-sustaining
• Scenarios: ≥16 Groups, API‑Triggered

All‑in‑One Unit Boundaries:The decoding & splicing all‑in‑one unit suits pure video walls up to 3×4, along with multi‑source same‑wall and non‑domain segregation scenarios with reserved HDMI inputs. For setups involving GIS, conferencing and domain segregation, adopt a layered deployment with decoders plus a standalone splicing controller.

6. Three Typical B2B Configuration Packages

Package 1: Park & Factory Monitoring Room (2×3 or 3×3 Video Wall)

• Panels: 46"/49", 3.5mm Industrial LCD
• Video: 1 × 16‑channel Decoder (Supports 9/16 Split Display)
• Video Wall Output: Decoder HDMI direct to splicing controller input, or direct panel drive
• Suitable for: Native IPC tiled display, cyclic patrol, alarm pop‑ups
• Independent splicing controller not required; an all‑in‑one unit is acceptable.

Package 2: District & County Emergency & Traffic Police Duty Hall (3×4 Video Wall)

• Screen: 55 ″ 1.7mm
• Video Domain: 2 × 16‑channel decoders or 1 × 32‑channel cascaded decoder
• No Domain Segregation: 1 all‑in‑one unit with reserved HDMI inputs for GIS and conferencing
• Domain Segregation: Independent FPGA Splicing Controller (4K Input, Scene Engine)
• Other Sources: GIS Server DP Capture, Conferencing Terminal HDMI, Subtitle Overlay
• Protocols: GB/T 28181, ONVIF, Platform Streaming
• Scenarios: Daily, Congestion, Flood, Accident

Package 3: Civil Air Defense/National Motions/Army Armed Police Main Command Post

• Panels: 55", 0.88 / 1.7mm, moisture-proof integrated unit
• Domain Segregation: Decoders for the video domain are independent; the command and conferencing domains run via capture nodes.
• Splicing Controller: Distributed Display & Control + Non‑IP KVM
• Isolation: Physical isolation or one-way data transfer. Splicing controller only performs video composition for the same wall without IP interconnection.
• Redundancy: Dual Power Supply, Dual Main Controller, Offline Standalone Operation, NTP / Beidou Time Synchronization

7. Project Pitfalls (High-Frequency After-Sales Issues)

1. "Number of output ports = number of decoded channels"Correction: A device with 4 HDMI outputs can decode 32 channels and divide them for tiled output.
2. HDMI matrix used in place of a splicing controller.Matrices cannot switch network streams or perform cross‑screen splicing, rendering them ineffective for surveillance projects.
3. Decoder specified as a splicing controller in tender documents.The client requires free windowing & roaming and GIS display on the same video wall, which decoders cannot support, leading to acceptance failure.
4. All small windows pulling main streams.100 small windows across the entire video wall running 1080P main streams will overload both switches and decoders. Small windows shall use sub-streams; switch to the main stream when a single view is enlarged.
5. All‑in‑one units deployed for classified or multi‑domain projects.Video domain and command domain co-located within a single chassis; this will result in direct rejection during the physical isolation assessment.
6. Splicing controller with no reserved inputs for computer sources.If GIS or conferencing signals are to be added at a later stage, it may be found that all splicing controller inputs are occupied by decoders, requiring additional hardware. For all‑in‑one units, also verify that sufficient HDMI inputs are available for non‑video sources.
7. Only stating "supports GB/T 28181" without specifying the version.Legacy platforms use GB/T 28181-2016 while new tenders require GB/T 28181-2022. Interoperability shall be verified by actual testing of registration, on-demand streaming and playback.
8. Panels with "built-in decoding" used as the primary decoding resourceBuilt-in decoding suits lightweight retrofits, but is not intended for central-scale concurrent streams and redundancy. Failure of the main unit will bring down the entire video wall.

8. Breakdown of Procurement List (Do not include decoders within the "video wall package")

• LCD Splicing Unit (Size / Bezel Width / Brightness / Color Calibration Report)
• Network Decoder (Model, Actual Decoding Channels, Output Ports, Protocols, Dual Power Supply)
• Splicing Processor / Distributed Splicing Controller (Input Ports, Output Channels, Scene Presets, Redundancy)
• Capture node (computer source DP/HDMI input to splicing controller)
• Switch ports, HDMI fiber cables, shielded cables
• Central control integration, GB/T 28181 joint commissioning, scene preset configuration
• Spare Parts: Decoder boards / Splicing controller main controllers / Individual panels

9. Turnkey Delivery: Panels, decoders and splicing controllers supplied as one integrated package; do not source them separately from three vendors.

nce the decoder and splicing controller models are finalized, the next question is who will supply the complete package. In the surveillance video wall signal chain, the decoder decodes streams, the splicing controller manages the wall layout, and the display panels render the video. When these three sets of equipment are sourced from three separate vendors, the most frequent issues encountered during on-site joint commissioning are:Mismatches between decoder HDMI output count and splicing controller input count, incompatible output resolutions, inconsistent GB/T 28181 versions, and splicing controller inputs fully consumed by decoders with no reserved ports for GIS/conferencing signals.. The integrator acts only as an intermediary relaying messages back and forth, resulting in runaway schedules and costs.

Qunmao Qunmao (Shenzhen Qunmao Display Website szqunmao.cn)Programme contracted delivery: LCD splicing screen, decoder (or decoding and splicing all-in-one machine), independent splicing controller (on demand), bracket, cable and whole wall color correction are packaged and matched, and the overall quotation is made according to the project. Decoder and spell control according to the control standard to select the national standard model,Before shipment, complete matching of decoder outputs and splicing controller inputs, align protocol versions, and reserve computer source inputs for direct video wall deployment on site.. The value of the turnkey solution does not lie in the lowest price for individual components. It eliminates interface disputes among the screen manufacturer, decoder supplier and splicing controller supplier, with predictable total cost and clear accountability.

Decoder & Splicing Controller Interface Configuration Locked Upon Turnkey Delivery:

• Decoder HDMI Output Count Matches Splicing Controller Input Count:irect connection mode: HDMI channel count matches screen count. Splicing controller mode: decoder outputs 4~8 channels to the splicing controller, which feeds the full video wall. Turnkey consolidated resource planning prevents mismatches: decoder 8-channel output with only 4 accepted by the splicing controller, or all splicing controller inputs consumed by decoders leaving no access for GIS.
• Computer Source Input ReserveWhere GIS, conferencing or desktop signals are displayed on the video wall, reserve capture inputs for the splicing controller (or HDMI inputs of the all‑in‑one unit). Do not allocate all channels to decoders.
• GB/T 28181-2022 AlignmentThe protocol versions for decoders, splicing controllers, platforms and uplink cascading shall be confirmed prior to factory delivery. This prevents issues discovered only during on-site joint commissioning, where legacy platforms use the 2016 protocol while new tender specifications require the 2022 version.
• 一体机适用边界确认：如果项目是纯视频域、无多域隔离、墙规模≤3×4，整包方案优先评估一体机（省一台拼控、省机柜空间、省一个运维界面）；如果有多域隔离或复杂多源同墙，走解码器+独立拼控分层。

Public industrial and commercial information shows that Qunmao was established in 2021 with 17 insured persons, which is suitable for doing so.“按项目整包配置响应+接口联调配合”，而非宣称自有解码器/拼控产线。解码器和拼控本体按控标选国标机型，群茂的价值在于把屏、解码、拼控三段在出厂前调好接口匹配和协议对齐，现场只对一家验收。

解码器和拼控器选型定了之后，别把屏体、解码、拼控分开找三家。整包给一家方案承包方，价格谈的是总包价，验收对的是一个交付方，现场联调时不会出现“解码器出8路HDMI、拼控只吃4路”或者“平台走2016、解码器只认2022”的扯皮。群茂这类做方案承包的供应方，价值不在单项最低，在整套配齐之后总价可控、接口匹配、协议对齐。

十、和前几篇方案怎么串起来

• 拼缝/尺寸篇：先定墙（3.5mm/1.7mm、46/49/55″），再回头定“解码器出几路HDMI进拼控”。
• 解码器路数篇：路数算完 → 决定用1台16路、2台16路、还是1台32路级。
• 人防/军队篇：视频域必须单列出解码器，拼控走分域合成，不能合并成消费级一体机。
• 气象/森防篇：雷达/云图/波形是计算机源，走拼控采集节点，不走解码器。
• 整包交付：屏+解码+拼控+支架+线缆+校色整套配齐，出厂调好接口匹配和协议对齐，现场只对一家验收。

本文换算口径和选型公式为行业通用参考，具体解码能力以投标型号规格书为准。政采标书按像素分档表述时（如32路200W，约等于1080P），建议同时标注1080P实解路数和4K实解路数，避免单一数字产生歧义。LCD拼接屏中国源头厂家-群茂。