Blackmagic Forum

Hello,

Thanks for adding SRT support to the web presenters, has anyone had any luck using a custom SRT server and publishing to it?

I have been trying to push and SRT stream to mediamtx (open source RTMP/SRT server) which for a pulisher uses the following format:

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srt://192.168.0.40:8890?streamid=publish:mystream

I have tried all combinations of settings; for example setting the server to "srt://192.168.0.40:8890" and key to "publish:mystream" but i'm got getting a connection.

If i uses the RTMP output to that same software I have no issues, its just the SRT that seems to be having issues.

Anyone else had any luck?

Many Thanks

Spent some more time digging into this, as far as i've test so far the SRT part is working and I can see the SRT streaming comming through it just lacks any streamid, to identify the stream.

In the manual the guide hints to this but doesnt give any more useful information, than the xml block stream-id.

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<srt-extensions>
    <stream-id>
        <item key=”copy” value=”0”/>
    </stream-id>
</srt-extensions>


The guide then states:

Provides element with custom parameters for the stream ID. Each child element of stream-id has 1 or more item elements with a key/value pair.

What are these custom values, for example what does copy do when the value it 0 or 1 ?

Same issues here, i have made the Streaming XML setting... but don't work...
============================
<?xml version="1.0" encoding="UTF-8" ?>
<streaming>
<service>
<name>SRT CastR V55</name>
<servers>
<server group="Primary">
<name>CASTR</name>
<url>srt://mi.castr.io:9998</url>
<srt-extensions>
<stream-id>
<item key="copy" value="0"/>
</stream-id>
</srt-extensions>
</server>
</servers>
<profiles>
<profile>
<name>Streaming Low</name>
<config resolution="1080p" fps="25">
<bitrate>1000000</bitrate>
<audio-bitrate>128000</audio-bitrate>
<keyframe-interval>2</keyframe-interval>
</config>
</profile>
</profiles>
</service>
</streaming>
============================

blackmagic added Castr as supported platform but in rtmp mode , why they didnt added the SRT so

this is my try:
<?xml version="1.0" encoding="UTF-8" ?>
<streaming>
<service>
<name>Castr SRT</name>
<servers>
<server>
<name>Frankfurt</name>
<url>srt://fr.castr.io:9998</url>
</server>
<server>
<name>London</name>
<url>srt://uk.castr.io:9998</url>
</server>
</servers>
<profiles>
<profile>
<name>Streaming High</name>
<config resolution="1080p" fps="25">
<bitrate>6000000</bitrate>
<audio-bitrate>128000</audio-bitrate>
<keyframe-interval>2</keyframe-interval>
</config>
</profile>
<profile>
<name>Streaming Medium</name>
<config resolution="1080p" fps="25">
<bitrate>4500000</bitrate>
<audio-bitrate>128000</audio-bitrate>
<keyframe-interval>2</keyframe-interval>
</config>
</profile>
<profile>
<name>Streaming Low</name>
<config resolution="1080p" fps="25">
<bitrate>3000000</bitrate>
<audio-bitrate>128000</audio-bitrate>
<keyframe-interval>2</keyframe-interval>
</config>
</profile>
</profiles>
</service>
</streaming>

and what should i put in "Key" and "Passphrase" in Blackmagic Web Presenter setup interface

I'm having the same issue.
Regardless of what I tried, 100s different combinations of configs and destination servers/clients, I could not get my Web Presenter to transmit an SRT feed.

RTMP worked just fine.

I think a set of example config files would be very helpful for the start. Maybe also improve the documentation in the manual as I feel very dumb reading it as if I don't have pre-required knowledge.

I've also been pulling my hair over this. With little luck.

I can stream into vmix by using just the IP and port number in the URL. So at least we know SRT does actually work.

However, as stated above there are additional values required to stream into other platforms. At this time these are poorly documented.

I feel with the custom field you dont need to make the custom config file. Just use that.

Andre Augustin wrote:I feel with the custom field you dont need to make the custom config file. Just use that.

I tried that, also to no success

Andre Augustin wrote:I feel with the custom field you dont need to make the custom config file. Just use that.

You Stream to Youtube ? But me i want to Stream to another Plateforme SRT.

If you want to Use Youtube SRT yes i can use the Server in the List.

BUT i need to Use Custom SRT....

Anyone can Help us ??

thavben wrote:I've also been pulling my hair over this. With little luck.

I can stream into vmix by using just the IP and port number in the URL. So at least we know SRT does actually work.

However, as stated above there are additional values required to stream into other platforms. At this time these are poorly documented.

Same Here i can Stream with Vmix but i need to stream with tue WebPresenter HD :'(

Hi.
Maybe this help

On your xml config file add:

<server>
<name>SRT Destination Name</name>
<url>srt://destination_ip:port</url>
<srt-extensions>
<stream-id>
<item key="r" value="your_stream_key"/>
<item key="m" value="publish"/>
<item key="latency" value="your_latency_value"/>
</stream-id>
</srt-extensions>
</server>

For playing stream use:
"srt://destination_ip:port?streamid=#!::r=your_stream_key,m=request"

regards,
Laur

I spoken to people who have this working and apparently it’s crucial to use Main profile encoding for your H264.

I've reached out to blackmagic support to ask for more details regarding the streamid and its limited documentation in the manual. Will post back here if I hear back from them. (support have passed a few questions to development team).

I've played with a few different SRT servers and yes the SRT stream sends and starts correctly but it doesnt send the streamid option. (https://github.com/Haivision/srt/blob/m ... control.md) which for some SRT servers is a requirement, to identify/authorize streams.

Hi, Yes I would also like bit more information on the xml documentation I've succeeded to stream locally to a obs instance. But are unable to get anything out to castr.com and can’t test youtube as youtube srt[Beta] is not a option yet for me. If anyone maybe knows a bit more on the additional parameters like latency caller listener etc how to set them properly via the xml file it would be much appreciated

to stream to castr using Web Presenter Custom SRT
first : get yours stream id and i should be like this
#!::r=live_1234567891234567899,password=123456789,m=publish

so the r=live_1234567891234567899
and m=publish

and this should be added to the Web Presenter Custom XML

<server>
<name>Castr SRT Frankfurt</name>
<url>srt://fr.castr.io:9998</url>
<srt-extensions>
<stream-id>
<item key="r" value="live_1234567891234567899"/>
<item key="m" value="publish"/>
<item key="latency" value="200"/>
</stream-id>
</srt-extensions>
</server>

Big THX laurfb

I've got it working for castr Thanks to Laur for the pointer!

For those connecting to castr here are some pointers:
(I've used made-up values for anyone concerned)

Stream ID is anything after the R-value. So in separate field view

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#!::r=live_0b661090f5r111ed83a8999f85f1e229,password=714b56af,m=publish

Becomes:

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<item key="r" value="live_0b661090f5r111ed83a8999f85f1e229/>

Oddly you don't need to insert a password at this time. (this may change)

My config (For UK Castr, change URL as appropriate):

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<?xml version="1.0" encoding="UTF-8"?>
<streaming>
<service>
<name>SRT Castr V1</name>
<servers>
<server group="Primary">
<name>CASTR</name>
<url>srt://uk.castr.io:9998</url>
<srt-extensions>
<stream-id>
<item key="r" value="live_XXXXXXXXXXXXXX/>
<item key="m" value="publish"/>
<item key="pkt_size" value="1316"/>
<item key="latency" value="80"/>
</stream-id>
</srt-extensions>
</server>
</servers>
<profiles default="Streaming High">
         <profile>
            <name>Streaming High</name>
            <low-latency/>
            <config resolution="1080p" fps="60" codec="H264">
               <bitrate>9000000</bitrate>
               <audio-bitrate>128000</audio-bitrate>
               <keyframe-interval>2</keyframe-interval>
            </config>
            <config resolution="1080p" fps="30" codec="H264">
               <bitrate>6000000</bitrate>
               <audio-bitrate>128000</audio-bitrate>
               <keyframe-interval>2</keyframe-interval>
            </config>
         </profile>
         <profile>
            <name>Streaming Medium</name>
            <low-latency/>
            <config resolution="1080p" fps="60" codec="H264">
               <bitrate>7000000</bitrate>
               <audio-bitrate>128000</audio-bitrate>
               <keyframe-interval>2</keyframe-interval>
            </config>
            <config resolution="1080p" fps="30" codec="H264">
               <bitrate>4500000</bitrate>
               <audio-bitrate>128000</audio-bitrate>
               <keyframe-interval>2</keyframe-interval>
            </config>
         </profile>
         <profile>
            <name>Streaming Low</name>
            <low-latency/>
            <config resolution="1080p" fps="60" codec="H264">
               <bitrate>4000000</bitrate>
               <audio-bitrate>128000</audio-bitrate>
               <keyframe-interval>2</keyframe-interval>
            </config>
            <config resolution="1080p" fps="30" codec="H264">
               <bitrate>3000000</bitrate>
               <audio-bitrate>128000</audio-bitrate>
               <keyframe-interval>2</keyframe-interval>
            </config>
         </profile>
      </profiles>
</service>
</streaming>

Has anyone had any luck with mediamtx instead of Castr? I managed to stream to Castr via SRT with the Web Presenter 4K, thanks to this thread But I cant get it to work with "mediamtx" or "datarhei restreamer" as local SRT servers. I want to try SRT instead of RTMP because H265 seems to not work right with RTMP (but H265 offers 10 bit..). Mediamtx does receive the stream but it cant relay it correctly or record it in one file. I hope that SRT solves this but mediamtx must expect a different format for the URL or the ID. From the SRT documentation it becomes clear that this "Stream ID" used by the Web Presenter is a (fairly new?) optional feature of the protocol so maybe the integrations of mediamtx are just not up to date or cant use the feature and the Web Presenter requires it? Or did anyone here find a way to get it working?

Kind Regards,
Lennart

Hi, anyone has luck with making this working with custom SRT streams?

I have a streamID to set but I don't need to set "m=publish" , i do have 1 link for publishing which includes the streamID, which is essentially my stream key.

this is an example of my SRT url:

srt://server.mysrtserver.com:8080?strea ... ystreamkey

how do i setup that URL into the blackmagic xml file? because using it as the URL in the textfield doesn't work at all.

nebelpa wrote:Has anyone had any luck with mediamtx instead of Castr?

Yes, i had to make a fork of it and make some code changes to the https://github.com/datarhei/gosrt lib that mediamtx and to mediamtx itself to understand the srt access protocol.

This config worked for a customer when using a Blackmagic Web Presenter 4K and streaming over SRT to OvenMediaEngine (which requires streamid to be specified and no b-frames):

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<streaming>
    <service>
        <name>SRT-Sample-Service</name>
        <servers>
            <server group="Primary">
                <name>Some-server-name</name>
                <url>srt://your-server-domain.com:9999</url>
                <srt-extensions>
                    <stream-id>
                        <item key="streamid" value="srt://your-server-domain.com:9999/appname/streamname123"/>
                    </stream-id>
                    <stream-latency>
                        <item key="latency" value="2000"/>
                    </stream-latency>
                </srt-extensions>
            </server>
        </servers>
        <profiles default="Streaming Sample">
            <profile>
                <name>Streaming Sample</name>
                <low-latency/>
                <config resolution="1080p" fps="30" codec="H264">
                    <bitrate>6000000</bitrate>
                    <audio-bitrate>128000</audio-bitrate>
                    <keyframe-interval>2</keyframe-interval>
                </config>
            </profile>
        </profiles>
    </service>
</streaming>

It seems you have to use a separate srt-extensions subsection for each parameter for it to work. The name of these subsections (for example "stream-id" or "stream-latency") seems to not matter, but has to be unique.
The latency parameter has to be specified in milliseconds (2 seconds in this example).

For me right now it's not possible to stream to a custom server with all the posted xmls here... maybe anyone has a hint how to get a working webpresenter 4k with a custom srt server Firmware is 3.5

I found a working solution for those using Castr.io to distribute SRT stream.

Duplicate the existing YouTube SRT (Beta) service and only change the items show below:

<LiveStream serviceName="YouTube SRT (Beta)" url=" srt://southafrica.castr.io:9998" key="r" streamIdExtensions="ff6f82408c7d22eca72c791fd332f8199" lowLatency="False" streamDownConvertMode="None">

<bitrate low="6000000" high="9000000"/>
<audioBitrate low="128000" high="128000"/>
</LiveStream>

For the streamId you only copy anything after 'r=' and before the comma.

#!::r=ff6f82408c7d22eca72c791fd332f8199,m=publish

Apologies for reviving an old thread...

With the help from this thread, I was able to get SRT to Castr working. BUT, the latency is very low...usually a good thing, but I'm streaming over Starlink so the connection isn't super consistent. As a result, I get tearing and artifacts pretty often. I need reliable quality...latency isn't important to me.

I tried various different latency settings using <item key="latency" value="xyz"/> but none of them seem to affect the end result of latency (and resulting random artifacts when delay spikes). Watching the monitor output of my Web Presenter compared to the player in Castr, it looks like latency is very low...possibly sub-second.

Has anyone had luck getting the latency setting to work properly? I've tried 2000, 5000, 10000 and none have any effect compared to just omitting the latency item key from the XML.