Before ordering a 4-channel SDI capture card, confirm that your complete setup can capture every required input at the same time. That means checking the video format on each channel, the host computer's PCIe connection, the driver and the production software together. Then test a sample under the workload you plan to deploy.
A useful purchase specification goes beyond "four SDI ports, 1080p60." It identifies the cameras, computer, application and recording requirements, and defines what the sample must demonstrate. For a multi-camera studio, lecture capture system or live production workstation, this gives you a practical basis for comparing quotations and approving hardware.
In this guide
Define what all four inputs must do
Start with the signal path. Confirm which connectors accept video, whether all required inputs operate independently, and how the application selects each channel. If your project needs four separate recordings, include that requirement explicitly. A preview showing four pictures does not establish that the software can record four separate files.
Write down the exact output format of every source. Keep distinctions such as 1080p50, 1080p59.94, 1080p60 and 1080i50 in the specification. Also state whether the sources will use identical formats or a mixture, and whether you need embedded audio from each input. Ask for confirmation of the complete combination you intend to use.
For example, your requirement might be four independent 1080p50 camera inputs, each available in the application, with a switched program recording. Another project might need separate recordings from every camera. These are different acceptance tasks even when both projects use a quad SDI capture card.
Check the computer that will host the card
A PCI Express (PCIe) capture card must match the motherboard's available connection. Confirm the required PCIe generation and lane count, then check the motherboard manual for the electrical connection of the intended slot. Include the graphics card, storage devices and other expansion cards in that review. Some full-length slots operate with fewer electrical lanes and share resources with storage connections, as illustrated in this ASUS motherboard manual.
Ask the computer supplier to confirm the slot arrangement for the fully populated machine. A test carried out with one expansion card removed does not establish that your final configuration will behave the same way. Record the slot used during sample validation so the production build can reproduce it.
Check physical fit before ordering multiple units. The case must accommodate the card and its bracket, allow access to all SDI cables, and leave the cooling arrangement clear. Perform the sustained workload test with the intended case, cooling and expansion cards installed.
Verify the driver and application as a pair
Put the operating system version, driver version and production application version on the same test record. "Works with Windows" or "supports streaming software" leaves too much unspecified for a repeatable deployment.
For OBS Studio on Windows, the standard Video Capture Device source uses a driver that supports DirectShow output. OBS also provides a separate V4L2 source for Linux. These are software requirements to check against the proposed device and driver. They do not establish that every capture card supports every operating system. See the OBS video capture source documentation.
In your selected application, add each input and identify it clearly. Verify the requested resolution and frame rate, then check that changing one source selects or configures the intended channel. If the project needs embedded audio, confirm the available audio devices, channel mapping and monitoring behavior.
Use the software you will deploy for the acceptance test. Demonstrating capture in a supplier's utility is useful for checking the hardware, but the project also needs to work in your chosen OBS, vMix, Wirecast or custom application configuration.
Test the complete production workload
Begin with one known working video source and cable. Check each input separately, then connect all required sources and run them together. This sequence helps isolate a connector, source or configuration problem before adding the full workload.
Next, reproduce the planned production session: preview the inputs, switch scenes, route audio and record or stream as required. If separate camera recordings are part of the purchase requirement, run those alongside the program output. Review the resulting files as well as the preview.
Agree on a test duration that reflects the intended session length. Record the settings, start and finish times, interruptions and any frame or audio issues. "Passed a long test" is difficult to evaluate without the workload and duration attached.
When an issue appears, record where it occurs. A missing input picture, an application rendering problem, an encoding bottleneck and a network streaming interruption require different checks. Preserve the application logs and affected recordings so the supplier can investigate the same event.
Read each counter according to its definition. OBS uses dropped-frame reporting for streaming connection problems. vMix distinguishes source drops, rendering drops and resynchronization; its source-drop count can reflect camera timing as well as a bandwidth bottleneck. Check the individual inputs and recordings alongside these counters. See the OBS streaming connection guide and vMix statistics documentation.
Include the recovery actions your operators expect to use. Test a restart and application relaunch. If sources may be disconnected during a production session, agree on a signal-loss and reconnection test. Record whether capture resumes automatically or requires an operator action.
Use this sample acceptance checklist
Attach the completed checklist to the sample approval. Agree on pass criteria before testing, including permitted interruptions and recovery behavior for your application.
| Check | What to demonstrate | Evidence to keep |
|---|---|---|
| Channel access | Every required input is available independently and at the same time | Input labels and configuration screenshots |
| Video formats | Each source works at its specified resolution, frame rate and scan type | Source settings and recorded samples |
| Host connection | The card operates in the intended slot with the complete expansion configuration | Motherboard model, slot and hardware list |
| Driver and software | The required application exposes and captures the intended channels | OS, driver and application versions |
| Audio | Required audio inputs are mapped correctly and remain aligned with video during the agreed test | Audio settings and sample recordings |
| Production workload | Preview, switching, recording and streaming functions work in the required combination | Test duration, logs and output files |
| Recovery | Agreed restart and signal-reconnection actions produce the expected result | Steps, observed behavior and operator actions |
Keep the approved hardware revision and driver package with these records. If the card, host configuration or software changes later, review which tests need to be repeated before deployment.
Prepare a quote that matches your project
Send the supplier your source list, simultaneous input requirements, motherboard or workstation model, operating system and production software. Add the recording requirements, target quantity, market and schedule. For a private-label order, include the label, packaging and documentation requirements in the same request.
Compare quotations against that shared scope. Ask each supplier to identify what the quoted configuration includes, which requirements have been demonstrated, and which need sample validation. This makes differences in price easier to assess.
For a PURPLELEC project review, send us this completed requirement list with your preferred configuration. We can use it to discuss the sample scope and quotation. Approve the order against the configuration and test record that match your production system.
