# Flow Manager
import NewBadge from '../../../components/NewBadge.astro';
Flow Manager routes signals through a configured flow engine. Each flow belongs to an engine and contains one input plus one or more outputs.
## Read the Flow List
The summary shows running, stopped, error, and engine-offline counts. Search covers flow names and configured input or output values. Sort the columns or collapse flows to keep a large production readable.
If a flow engine is offline, its flow controls are unavailable. Ask an administrator to check the engine before changing the flow.
## Create a Flow
1. Select **Create Flow**.
2. Enter a clear flow name.
3. Select the flow engine.
4. Create the flow.
5. Add and configure its input and outputs.
The protocols offered by the editor depend on the selected engine and whether you are adding an input or output.
## Configure an Input or Output
1. Select **Add Input** or **Add Output**.
2. Enter a name and choose a protocol. An existing item's protocol cannot be changed.
3. Complete the protocol fields shown by Studio.
4. Select **Create** or **Save Changes**.
Use **Edit settings** on an existing input or output to review its current protocol configuration. The protocol is fixed after creation, but the fields for that protocol can still be updated.
### Choose a flow type
Choose the protocol based on where the signal originates, where it needs to go, and how it will be viewed.
| Flow type | Available as | Use it when |
| --- | --- | --- |
| **NDI** | Input and output | The source and destination are NDI-capable production tools in the same connected production environment. |
| **SRT** | Input and output | The signal must cross the public internet or another routed network where resilience, configurable latency, or encryption matters. |
| **WHEP** | Output | Viewers need a low-latency WebRTC feed in a compatible browser or Feed Manager. |
#### NDI
Use NDI to move video between NDI-capable production applications and systems that can discover or reach one another in the production network. It is a good fit for internal handoffs such as sending a source to a switcher, multiviewer, recorder, or another processing tool in the same environment.
:::note
An NDI Discovery Server must be deployed and running in the environment before you use an NDI flow. Ask an administrator to confirm the server is available if NDI sources do not appear.
:::
Configure the **NDI Name** so it matches the source you want to receive or the name you want the output to advertise. Select the required frame rate. NDI inputs also expose bitrate and encoding profile controls in Studio.
NDI depends on the environment's NDI discovery and network configuration. If the named source does not appear, confirm the source name, flow-engine readiness, and NDI discovery path before recreating the flow.
#### SRT
Use SRT for contribution or delivery between locations, cloud environments, or systems connected through the internet. Its latency buffer can recover from some network disruption, with the tradeoff that a larger value adds more delay.
SRT is available for both inputs and outputs. Configure:
- **Caller** when this endpoint should initiate the connection to a remote host.
- **Listener** when this endpoint should wait for the other side to connect. Studio fixes the listener host to `0.0.0.0`.
- **Port**, **Latency**, and **Max Bandwidth** to match the other endpoint and the production network.
##### Encryption
Set **Passphrase** and **Key Length** when the path requires encryption. Both endpoints must use matching values.
##### Stream ID
Set **Stream ID** when the receiving service uses it to identify or route the connection.
Select **Copy URL** when you need the generated SRT address. Confirm firewall and security-group rules before the production; changing caller/listener mode does not open the required network path.
#### WebRTC outputs (WHEP)
Use WHEP for low-latency browser monitoring rather than as a contribution input. In the Flow Manager editor, select **WebRTC** when adding the output. Studio then generates a WHEP endpoint for that WebRTC output.
Set the output bitrate to a value appropriate for the picture and the viewers' available bandwidth. After creating the output:
1. Select **Copy URL** to copy its WHEP endpoint.
2. Select **Copy to new Feed** to create a WHEP entry in Feed Manager from the same endpoint.
**Copy to new Feed** appears only when editing a saved WebRTC output and Studio can generate its WHEP URL. It is not shown while creating the output or when the flow engine has no usable domain.
The flow engine must have a working externally reachable domain before Studio can generate a usable WHEP URL. Test playback from the same kind of network the production viewers will use.
## Operate Flows
Start or stop a complete flow from its header. You can also control the input or each output independently. Select multiple flows to use bulk start or stop, and review the confirmation before applying it.
### Live input statistics
Use the statistics control on a running item to view available live data such as uptime and bitrate. Status mismatches between a flow and its input or outputs are highlighted for attention.
:::caution
Deleting a flow, input, or output removes its configuration. Verify downstream destinations before changing a live signal path.
:::