Multicast

OvenMediaEngine can pull MPEG-2 TS input delivered over UDP multicast. The Multicast Provider uses the multicast:// URL scheme and creates streams through StreamMap or the Stream Creation API.

Item	Description
Container	MPEG-2 TS
Transport	UDP Multicast
Codec	H.264, H.265, AAC
Additional Features	SCTE-35 event forwarding

Configuration

To use Multicast, enable the <Provider> in the <Application>.

Bind

Bind settings are optional and are used only when you need to tune input socket processing or the UDP receive buffer size:

<!-- /Server/Bind -->
<Bind>
    <Providers>
        ...
        <Multicast>
            <WorkerCount>1</WorkerCount>
            <ThreadPerSocket>false</ThreadPerSocket>
            <ReceiveBufferSize>8388608</ReceiveBufferSize>
        </Multicast>
        ...
    </Providers>
</Bind>

Property	Description
WorkerCount	Number of worker threads used to process input sockets.
ThreadPerSocket	Whether to use a dedicated thread for each socket. If set to true, socket-specific threads are used instead of WorkerCount.
ReceiveBufferSize	Size of the UDP receive buffer. Adjust this in environments with high bitrate input or large bursts.

Application

Enable the Multicast Provider per Application:

<!-- /Server/VirtualHosts/VirtualHost/Applications/Application -->
<Providers>
    ...
    <Multicast>
        ...
    </Multicast>
    ...
</Providers>

StreamMap

Multicast streams declared in StreamMap are created automatically when the Application starts:

<!-- /Server/VirtualHosts/VirtualHost/Applications/Application -->
<Providers>
    <Multicast>
        <StreamMap>
            <Stream>
                <Name>news_hd</Name>
                <source />multicast://239.1.1.10:5000</Source>
                <ProbeTimeoutMsec>3000</ProbeTimeoutMsec>
            </Stream>
            <Stream>
                <Name>sports_hd</Name>
                <source />multicast://239.1.1.11:5000?interface=eth1</Source>
                <ProbeTimeoutMsec>5000</ProbeTimeoutMsec>
            </Stream>
        </StreamMap>
    </Multicast>
</Providers>

Property	Description
Name	Stream name to be created inside OvenMediaEngine.
Source	Multicast input URL.
ProbeTimeoutMsec	Maximum time, in milliseconds, to wait for input metadata. Default: 3000.

Multiple streams in the same Application can reference the same multicast source.

Pull timeout and retry

Input timeout and retry count are configured in Origins/Properties:

<!-- /Server/VirtualHosts/VirtualHost -->
<Origins>
    <Properties>
        <NoInputFailoverTimeout>3000</NoInputFailoverTimeout>
        <RetryCount>3</RetryCount>
    </Properties>
</Origins>

Property	Description
NoInputFailoverTimeout	If no input packets arrive for the configured time, the stream is stopped and a reconnect is attempted.
RetryCount	Maximum number of reconnect attempts.

Source URL format

The following URL formats are supported:

multicast://239.1.1.1:5000
multicast://239.1.1.1:5000?interface=eth0
multicast://[ff05::111]:5000
multicast://[ff05::111]:5000?interface=eth0

The only supported query parameter is interface:

Property	Description
interface	NIC name to use when joining the multicast group. If omitted, the OS selects the interface automatically.

Limitations:

• Paths are not supported. The URL path must be empty or /.
• Hostnames can be used. In that case, OvenMediaEngine resolves the hostname and uses the first result.
• The resolved hostname result must be in the multicast IP range.

Pulling streams using the Stream Creation API

Multicast streams can also be created through the Stream Creation API.

{
  "name": "channel1",
  "urls": [
    "multicast://239.1.1.1:5000"
  ],
  "properties": {
    "persistent": false
  }
}

For more information, see the REST API documentation.

Notes

• If a new sender starts on the same group and port, the provider detects it and attempts a reconnect.
• During reconnect, the new input track layout is compared against the previously published layout.
• The input metadata must be available within ProbeTimeoutMsec for the stream to be published.