Scrolling Text

Here’s some technical information about providing DLS to the multiplex.

What is DLS?

DLS (Dynamic Label Segment) is the scrolling text shown on DAB radios.

Typical examples include:

Song title and artist
Programme name
Presenter information
Promotional messages
Website or contact details

DLS updates automatically when metadata is sent to the multiplex.

How We Receives DLS Metadata

Our technical partners, Digris, supports three ways of updating DLS:

ICY Mode – metadata read directly from your audio stream
PUSH Mode – your system sends metadata directly to Digris
PULL Mode – Digris retrieves metadata from a URL you host

For most stations, PUSH mode is the most reliable option.

Option 1: ICY Mode

Best for

Stations already sending metadata through Icecast or Shoutcast.

How it works

Digris reads the stream title directly from your audio encoder.

Example metadata:

Coldplay - Viva La Vida

Requirements

Stream metadata must be enabled
Encoder must pass ICY metadata correctly
Metadata must update automatically from playout software

Common checks

If DLS does not appear:

Confirm metadata is visible in VLC or another stream player
Confirm your encoder is not stripping metadata
Confirm relay servers preserve ICY headers

Option 2: PUSH Mode (Recommended)

Best for

Stations wanting immediate and reliable DLS updates.

How it works

Your playout system or middleware sends metadata directly to Digris using an API.

Typical workflow:

Playout system → Metadata sender → Digris → DAB radios

Advantages

Near real-time updates
More reliable than stream scraping
Works independently of encoder metadata

Example API Calls

The Digris platform accepts DLS updates via HTTP POST requests.

Endpoint:

https://mc-uk.digris.net/api/v1/set_dls

You will normally receive:

Service ID
API token

To obtain your access key, please email support@northlondondigitalradio.com.

Your station should send metadata whenever content changes.

Option A: Send a complete DLS message

Use dls when you want to send the full scrolling text as one string.

Example JSON Payload

{
  "id": "your_service_id",
  "token": "YOUR_API_TOKEN",
  "dls": "Taylor Swift - Anti-Hero"
}

Example cURL Request

curl -X POST "https://mc-uk.digris.net/api/v1/set_dls" \
  -H "Content-Type: application/json" \
  -d '{
    "id": "your_service_id",
    "token": "YOUR_API_TOKEN",
    "dls": "Taylor Swift - Anti-Hero"
  }'

Option B: Send artist and title separately

Use artist and title when your playout system provides those fields separately.

Example JSON Payload

{
  "id": "your_service_id",
  "token": "YOUR_API_TOKEN",
  "artist": "Taylor Swift",
  "title": "Anti-Hero"
}

Example cURL Request

curl -X POST "https://mc-uk.digris.net/api/v1/set_dls" \
  -H "Content-Type: application/json" \
  -d '{
    "id": "your_service_id",
    "token": "YOUR_API_TOKEN",
    "artist": "Taylor Swift",
    "title": "Anti-Hero"
  }'

Important Notes

The API expects the service identifier field to be called id

The API token should be included in the JSON body as token.

To send a complete DLS message, use the dls field.

To send track information, use both artist and title.

Do not send title on its own as the complete DLS message. If you want to send one complete line of text, use dls instead.

Example PHP Request

<?php

$url = 'https://mc-uk.digris.net/api/v1/set_dls';

$data = [
    'id' => 'your_service_id',
    'token' => 'YOUR_API_TOKEN',
    'dls' => 'Taylor Swift - Anti-Hero'
];

$headers = [
    'Content-Type: application/json'
];

$ch = curl_init($url);

curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_POST, true);
curl_setopt($ch, CURLOPT_HTTPHEADER, $headers);
curl_setopt($ch, CURLOPT_POSTFIELDS, json_encode($data));

$response = curl_exec($ch);

if (curl_errno($ch)) {
    echo 'Error: ' . curl_error($ch);
} else {
    echo $response;
}

curl_close($ch);

Example Python Request

import requests

url = "https://mc-uk.digris.net/api/v1/set_dls"

payload = {
    "id": "your_service_id",
    "token": "YOUR_API_TOKEN",
    "dls": "Taylor Swift - Anti-Hero"
}

headers = {
    "Content-Type": "application/json"
}

response = requests.post(url, json=payload, headers=headers)

print(response.status_code)
print(response.text)

import requests

url = "https://mc-uk.digris.net/api/v1/set_dls"

payload = {
    "service_id": "your_service_id",
    "token": "YOUR_API_TOKEN",
    "text": "Taylor Swift - Anti-Hero"
}

headers = {
    "Content-Type": "application/json"
}

response = requests.post(url, json=payload, headers=headers)

print(response.status_code)
print(response.text)

Option 3: PULL Mode

Best for

Stations already publishing metadata on a public URL.

How it works

Digris regularly checks a URL for updated metadata.

Example URL:

https://yourstation.co.uk/metadata.json

Digris retrieves the text automatically.

Example JSON Feed

Your station hosts a JSON file.

Example:

{
  "text": "Coldplay - Yellow"
}

Digris polls this URL at intervals.

Recommended DLS Formatting

Keep text short

Many radios truncate long messages.

Good

Taylor Swift - Anti-Hero

Avoid

Now playing Taylor Swift with the hit song Anti-Hero from the Midnights album

Ideal length

For best compatibility across radios, aim for:

16–64 characters where possible
Clear spacing
Minimal punctuation
Avoid ALL CAPS

Longer messages are supported up to 128 characters, but some receivers may truncate or scroll slowly.

Good DLS Examples

Music station

Dua Lipa - Houdini

Speech station

Breakfast with James Ross

Promo message

Listen again at yourstation.co.uk

Troubleshooting

No DLS appearing?

Check:

Metadata source configured correctly
Correct service ID
API authentication valid
Stream metadata enabled
Metadata updating at source

Delayed updates?

Possible causes:

Polling interval in PULL mode
Automation software delay
Metadata cache

Wrong text showing?

Check:

Old metadata stuck in encoder
Multiple metadata sources active
Incorrect service mapping

Recommended Setup for Udab Stations

For most stations on Udab:

PUSH mode for reliable updates
ICY mode if metadata already exists in your stream
PULL mode if you host metadata externally

PUSH mode is generally the best option for accurate, fast updates.

For more information contact support@northlondondigitalradio.com

Testing DLS (Scrolling Text) on Udab via Digris

Before integrating DLS into your playout or automation system, you can test metadata updates manually using the Digris tools below.

Testing Form

Use the Digris testing form to confirm that your metadata can be submitted correctly.

Testing Form URL

https://mc-uk.digris.net/test

This page is useful for:

Checking whether authentication works
Confirming your service ID is correct
Verifying that DLS updates are being accepted
Troubleshooting submissions

Manual Metadata Form

Digris also provides a simple web form for manually submitting DLS text.

Form URL

https://mc-uk.digris.net/form

This is useful for:

Quick testing without writing code
Verifying how DLS appears on radios
Checking timing and update behaviour
Testing metadata before automation is configured

Suggested Testing Workflow

Start with the manual form to confirm your service can receive DLS updates.
Confirm that the text appears correctly on supported radios.
Test API requests using cURL, PHP, Python, or your preferred integration method.
Connect your playout or automation system.
Monitor live updates to confirm reliable metadata delivery.

Common Testing Issues

DLS does not appear

Check:

Correct service ID
Valid authentication credentials
Metadata being submitted to the correct endpoint
Station service configured correctly within Digris

Updates delayed

Possible causes:

Metadata cache
Polling delay
Radio receiver refresh timing

Wrong text displayed

Check:

Old metadata cached in encoder or middleware
Multiple metadata sources sending updates
Incorrect mapping between service and metadata source

Need Access?

To obtain your access key or service details, please email:

support@northlondondigitalradio.com