Low-Latency DASH and HLS streaming

OvenMediaEngine supports HTTP based streaming protocols such as HLS, MPEG-DASH(Hereafter DASH), and Low-Latency MPEG-DASH with CMAF(Hereafter LLDASH).

Title	Functions
Delivery	HTTP for HLS and DASH HTTP 1.1 chunked transfer for LLDash
Security	TLS (HTTPS)
Format	TS for HLS ISOBMFF for DASH CMAF for LLDASH
Codec	H.264, AAC

OvenMediaEngine will support Low-Latency HLS in the near future. We are always keeping an eye on the decision from Apple inc.

Configuration

To use HLS, Dash and LLDash, you need to add the <HLS> and<DASH> elements to the <Publishers> in the configuration as shown in the following example.

<Server version="8">
    <Bind>
        <Publishers>
            <HLS>
                <Port>80</Port>
            </HLS>
            <DASH>
                <Port>80</Port>
            </DASH>
        </Publishers>
    </Bind>
    <VirtualHosts>
		    <VirtualHost>
            <Applications>
                <Application>
                    <Publishers>
                        <HLS>
                            <SegmentDuration>5</SegmentDuration>
                            <SegmentCount>3</SegmentCount>
                            <CrossDomains>
                                <Url>*<Url>
                            </CrossDomains>
                        </HLS>
                        <DASH>
                            <SegmentDuration>5</SegmentDuration>
                            <SegmentCount>3</SegmentCount>
                            <CrossDomains>
                                <Url>*<Url>
                            </CrossDomains>
                        </DASH>
                        <LLDASH>
                            <SegmentDuration>5</SegmentDuration>
                            <CrossDomains>
                                <Url>*<Url>
                            </CrossDomains>
                        </LLDASH>
                    </Publishers>
                </Application>
            </Applications>
        </VirtualHost>
    </VirtualHosts>
</Server>

Element	Decscription
Bind	Set the HTTP port to provide HLS and DASH. LLDASH and DASH are provided on the same port, and DASH and HLS can be set to the same port.
SegmentDuration	Set the length of the segment in seconds. The shorter the <SegmentDuration>, the lower latency can be streamed, but it is less stable during streaming. Therefore, we are recommended to set it to 3 to 5 seconds.
SegmentCount	Set the number of segments to be exposed to *.mpd. The smaller the number of <SegmentCount>, the lower latency can be streamed, but it is less reliable during streaming. Therefore, it is recommended to set this value to 3. It doesn't need to set SegmentCount for LLDASH because LLDASH only has one segment on OvenMediaEngine.
CrossDomains	Control the domain in which the player works through <CorssDomain>. For more information, please refer to the CrossDomain section.

CrossDomain

Most browsers and players prohibit accessing other domain resources in the currently running domain. You can control this situation through Cross-Origin Resource Sharing (CORS) or Cross-Domain (CrossDomain). You can set CORS and Cross-Domain as <CrossDomains> element.

Server.xml

<CrossDomains>
    <Url>*</Url>
    <Url>*.airensoft.com</Url>
    <Url>http://*.ovenplayer.com</Url>
    <Url>https://demo.ovenplayer.com</Url>
</CrossDomains>

You can set it using the <Url> element as shown above, and you can use the following values:

Url Value	Description
*	Allows requests from all Domains
domain	Allows both HTTP and HTTPS requests from the specified Domain
http://domain	Allows HTTP requests from the specified Domain
https://domain	Allows HTTPS requests from the specified Domain

Streaming

LLDASH, DASH, and HLS Streaming are ready when a live source is inputted and a stream is created. Viewers can stream using OvenPlayer or other players.

Also, you need to set H.264 and AAC in the Transcoding profile because MPEG-DASH and HLS use these codecs.

<OutputProfiles>
	<OutputProfile>
		<Name>bypass_stream</Name>
		<OutputStreamName>${OriginStreamName}</OutputStreamName>
		<Encodes>
			<Audio>
				<Bypass>true</Bypass>
			</Audio>
			<Video>
				<Bypass>true</Bypass>
			</Video>
		</Encodes>
	</OutputProfile>
</OutputProfiles>

When you create a stream, as shown above, you can play LLDASH, DASH, and HLS through OvenPlayer with the following URL:

Protocol	URL format
LLDASH	http://<Server IP>[:<DASH Port>]/<Application Name>/<Stream Name>/manifest_ll.mpd
Secure LLDASH	https://<Domain>[:<DASH TLSPort>]/<Application Name>/<Stream Name>/manifest_ll.mpd
DASH	http://<Server IP>[:<DASH Port>]/<Application Name>/<Stream Name>/manifest.mpd
Secure DASH	https://<Domain>[:<DASH TLSPort>]/<Application Name>/<Stream Name>/manifest.mpd
HLS	http://<Server IP>[:<HLS Port>]/<Application Name>/<Stream Name>/playlist.m3u8
Secure HLS	https://<Domain>[:<HLS TLSPort>]/<Application Name>/<Stream Name>/playlist.m3u8

If you use the default configuration, you can start streaming with the following URL:

• https://[OvenMediaEngine IP]:443/app/<stream name>_o/playlist.m3u8

• http://[OvenMediaEngine IP]:80/app/<stream name>_o/playlist.m3u8

• https://[OvenMediaEngine IP]:443/app/<stream name>_o/manifest.mpd

• http://[OvenMediaEngine IP]:80/app/<stream name>_o/manifest.mpd

• https://[OvenMediaEngine IP]:443/app/<stream name>_o/manifest_ll.mpd

• http://[OvenMediaEngine IP]:80/app/<stream name>_o/manifest_ll.mpd

We have prepared a test player that you can quickly see if OvenMediaEngine is working. Please refer to the Test Player for more information.