Datavideo NVS-35 and NVS-40 SRT workflows with Callaba
More live video workflow notes and product updates.
Datavideo encoder decision hub
Choose the Datavideo appliance from the production load, not from the SRT checkbox alone. NVS-35 is the compact path for one HDMI or SDI program with dual streaming and SD-card recording. NVS-40 is the rackmount choice for four inputs, per-channel encoding and drive-based recording. Callaba starts after the encoder: it receives the agreed SRT handoff and gives the team independent monitoring, Multiview, recording and route control.
Written by Iurii Pakholkov, founder of Callaba. Materially reviewed on July 18, 2026 against the official Datavideo sources below.
Choose NVS-35 or NVS-40 from the production load
| Model guide | Production fit | Verified boundary | When to choose it |
|---|---|---|---|
| NVS-35 | One event program, lecture, worship service or switched output that arrives over HDMI or SDI. | H.264 encoding, dual streaming, SRT support and SD-card recording. It is not a four-input encoder. | Choose when one source and a compact recording workflow are enough; verify the exact input, firmware and stream profile before the event. |
| NVS-40 | A rack workflow that must capture and encode several venue sources without adding four separate appliances. | Four HDMI inputs with channel 1 selectable between SDI and HDMI, H.264 encoding, four-channel capture/streaming and removable drive storage. | Choose from the complete channel, recording and monitoring load. Test every active channel together instead of validating only one preview. |
Pair the SRT connection role deliberately
Caller and listener describe which side initiates the session; they do not change which appliance encodes the program. Pick one relationship and test its real traffic direction.
| Connection path | Operational fit | Boundary to verify |
|---|---|---|
| NVS caller → Callaba listener | The encoder initiates the SRT session toward a public or privately reachable Callaba endpoint. | Usually the clearer cloud contribution pattern because the venue side makes the outbound connection. Align host, UDP port and every field exposed by the installed firmware. |
| Callaba caller → NVS listener | Callaba initiates toward an NVS endpoint that is intentionally reachable from the receiving network. | Use only when routing, NAT and firewall ownership make the device listener reachable and supportable. Do not expose the encoder administration interface as part of that design. |
Keep appliance, handoff and Callaba ownership separate
Datavideo appliance
The Datavideo appliance owns video and audio acquisition, H.264 encoding, its local recording media, stream profile and the source-side SRT role.
Transport contract
The handoff records the exact model and firmware, selected input or channel, codec profile, resolution, frame rate, bitrate, caller/listener pairing, host, UDP port, latency and any Stream ID or security field actually exposed by that firmware.
Callaba product layer
Callaba owns the matching SRT peer, arrival and transport evidence, browser Multiview, an independent cloud or private recording, downstream routes, playback and later automation.
Preflight the complete Datavideo-to-Callaba path
- Record the full model name and installed firmware. Confirm whether the production needs one program input or the NVS-40 multi-channel workload before creating endpoints.
- Choose one SRT relationship. Caller on the NVS and listener in Callaba is a practical venue-to-cloud default, but both reviewed model manuals also document device listener mode.
- Build the matching Callaba endpoint, then copy only the fields required by the selected Datavideo mode. Keep credentials and security values out of screenshots, analytics and public runbooks.
- Exercise the real network while every intended input, encode, stream and local recording is active. For NVS-40, a single healthy channel does not prove the four-channel show load.
- Verify video, every required audio source, transport telemetry, Multiview, a separate Callaba recording and the final downstream route. Keep local and Callaba recordings as independently checked artifacts.
Use the SRT Gateway hub to place this encoder in the wider architecture, the SRT Server guide to review receiver roles, and Callaba Multiview for the operator surface. After the product workflow is stable, use the SRT API documentation for secondary automation.
Official Datavideo evidence reviewed
Capabilities can change with firmware and hardware revisions. Reopen the official page and manual for the installed model before a production event.
- Datavideo NVS-35 product page and specifications — Official input, H.264, dual-streaming, recording and protocol boundary for NVS-35.
- Datavideo NVS-35 instruction manual — Official product-page manual download used for caller/listener fields and model-specific setup checks.
- Datavideo NVS-40 product page and specifications — Official four-input, H.264, storage, streaming and recording boundary for NVS-40.
- Datavideo NVS-40 instruction manual — Official product-page manual download used for SRT caller/listener pairing and preflight boundaries.
Frequently asked questions
What is the practical difference between NVS-35 and NVS-40?
NVS-35 is the compact one-program option with HDMI or SDI input, dual streaming and SD-card recording. NVS-40 is a rackmount four-input encoder/recorder with four HDMI inputs, channel 1 selectable between SDI and HDMI, per-channel workflows and removable drive storage.
Can NVS-35 and NVS-40 both use SRT caller and listener mode?
The reviewed Datavideo manuals document caller and listener modes for both models. Pair the opposite role in Callaba, then test the exact traffic direction through the real NAT and firewall path. Do not assume rendezvous mode without exact model and firmware evidence.
Does dual streaming make NVS-35 a two-input encoder?
No. Dual streaming describes multiple encoded outputs; it does not turn NVS-35 into the NVS-40 four-input architecture. Select NVS-40 when the production needs several independently acquired sources in one chassis.
Do these Datavideo models encode HEVC for SRT?
The reviewed official specifications list H.264/AVC for NVS-35 and NVS-40. Plan an H.264 handoff unless newer exact-model documentation and installed firmware explicitly prove a different codec path.
What must be tested before a Datavideo feed goes live?
Test the installed firmware, every active input and audio source, the chosen caller/listener pairing, sustained bitrate, recovery on the real network, local recording, Callaba transport evidence, Multiview, a separate Callaba recording and the final route.
Prove one complete NVS workflow before the production window
Choose the exact Datavideo model, run its full encode-and-record load, and validate the matching Callaba receiver before adding downstream destinations or automation.
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