January 23, 2020

Mobile streaming to Dacast and Akamai

Larix mobile SDK allows publishing live streams from mobile devices to wide variety of destinations like media servers and streaming services. Some destinations require special handling due to authorization or other concerns.

Dacast service provides a turn-key solution for live streaming. It uses Akamai CDN for ingest and delivery, making it simple for an average user to get it working. However, Akamai has its requirements for authorization and other stream parameters. Nimble Streamer allows publishing to Akamai already so we've added the same support into Larix Broadcaster.

Here is how you can get it working.

You may also read Streaming with the Larix Broadcaster Mobile App article from Dacast knowledge base to see other details of app setup.

Set up Dacast stream

We assume you already have Dacast account, so just open the dashboard and add a new stream.

Click on the stream name to see its full setup details. Click on Encoder tab on top to see the encoder setup details.

Click on Other RTMP encoder to see full parameters of RTMP connection.

Here you see Login and Password values which you will use later in Larix.

Now click on "Click if your encoder has one field" link to see a field with full URL for publishing.

Copy this full URL for later use, it should look like this:

rtmp://p.ep123456.i.akamaientrypoint.net/EntryPoint/dclive_1_150@123456

While you're in Dacast dashboard, check Publish settings tab to get a player page in order to check future result of your setup.

Now let's get to Larix setup.

Set up Larix Broadcaster

Larix Broadcaster is available for both Android and iOS platforms so just install it as usual.

Open the app and and enter settings by tapping on gear icon.

Tap on Connections -> New connection to enter a form below.

Name field can contain any alias you want for your connection. Larix Broadcaster allows streaming to multiple destinations simultaneously, so this is how you will distinct them from one another.
URL field defines the target destination. Insert the URL which you copied in the previous section.
Target type must be set to Akamai/Dacast.
Login and Password need ot be exactly like you've seen in Dacast connection settings.

Save connection, get back to connections list and make sure you select this new connection.
Now return to image preview screen and just hit the red button to start streaming.

Now check Dacast player page from previous section to watch the results.

Akamai

This setup procedure is applied the same way for publishing to Akamai CDN via RTMP. The publishing URL will have the same structure with same type of credentials. Larix Broadcaster target type is also "Akamai/Dacast". Please refer to Akamai website to learn more about its setup.

If you have any issues with this feature set, just let us know.

FFmpeg custom build support in Live Transcoder

Live Transcoder for Nimble Streamer supports a variety of decoding, filtering and encoding libraries. All the libraries which we have there were checked for reliability, performance and proper licensing before being added into the deployment package.

Our customers ask us to add some new libraries into Transcoder deployment package so they could be available by default in the UI. Mostly those are some existing open-source encoders, or commercial encoder libraries, or even custom encoders built by our customers themselves. However we couldn't add all the libraries which we are requested and this kept the doors closed for new functionality and gave bad experience to our customers.

To solve this problem, it's now possible to use custom builds of FFmpeg libraries to utilize any video and audio encoders as well as filters which are not supported in the default Transcoder package. Live Transcoder uses FFmpeg and its libraries for certain tasks under LGPL license which allows re-building it as necessary. So now you can just add more libraries if you need.

Linux packages of Live Transcoder can pick up custom libraries and use them for further encoding.
Re-building FFmpeg on Windows is also possible. If you are familiar with building FFmpeg for Windows you may try it, however we do not provide support for this case.

Here's how you may re-build FFmpeg and use it further.

1. Legal disclaimer

This article describes the process of building custom third-party FFmpeg libraries and using them in Softvelum Live Transcoder in addition to the libraries which are deployed as part of Live Transcoder package.

Every custom library which is a result of building FFmpeg has its own licensing terms. So every library must be examined for its licensing terms prior to any usage or distribution, including but not limited to the patent licensing terms.

Softvelum, LLC is not responsible for any license or patent infringement which can occur as a result of any FFmpeg custom build usage by Live Transcoder users.

2. Building FFmpeg

This section describes how you can build FFmpeg for further usage in Transcoder.

We strongly recommend you to try custom build approach in testing environment first. Once you get consistent result there, you may apply it to your production environment.

If something goes wrong after any of the steps and you'd like to revert it, just re-install Live Transcoder. This will rewrite all libraries with their default copies.

2.1 Making default FFmpeg build

To make sure your environment is ready for custom builds, let's start with building FFmpeg with the default libraries for Live Transcoder.

First, download the FFmpeg package. As required by FFmpeg license, we've uploaded the FFmpeg package and its build script on our website.

Second, run the shell script in the same directory where you've just downloaded FFmpeg. It has all commands needed for getting a working copy of FFmpeg. Its compiled libraries can be used with Live Transcoder as is.

You may get errors related to missing packages, like Freetype or Speex libraries. Just install respective packages using this command for Ubuntu

sudo apt install libfreetype6-dev libspeex-dev

and this command for CentOS

yum install freetype-devel speex-devel bzip2

You'll be able to proceed with building after that.

2.2 Making and using custom FFmpeg build

Now when you have FFmpeg ready for builds, you may add third-party encoder. This depends on what encoder you'd like to add, so you need to refer to your library documentation for more details on installation.

Having an encoder installed, you need to modify your build script to include it. Change your build script and modify the following line:

--enable-encoder=aac,png,mjpeg,customvideocodec,customaudiocodec \

Append your custom encoder name into that line. This is the name which is used within FFmpeg and which will later be used in Live Transcoder. In this case you can see "customvideocodec" and "customaudiocodec". You may also need to append additional lines for other parameters, so check library documentation for more information.

You can find examples of other custom build scripts in our github.

Once the build is over, you can use the new library.

2.3 Using libraries

You can ingest the libraries to Live Transcoder by copying them from "build/lib/" subdirectory of build directory into proper location.

Run this command on Ubuntu to see where Transcoder libraries are located:

dpkg -L nimble-transcoder

Most probably your directory will be /usr/lib/x86_64-linux-gnu/.

On CentOS you can run this command to see where it is:

rpm -ql nimble-transcoder

Once you find the location, you can re-write the libraries by copying from your build directory to Transcoder location.

2.4 Re-start Nimble Streamer

The last step to make those new libraries start working, is to re-start Nimble Streamer using the command required by your specific OS.

For Ubuntu it's this one:

sudo service nimble restart

You can find other OSes on installation page.

3. Using custom libraries in Live Transcoder

Now when you have the custom library available, you can start using it from your Live Transcoder web UI.

Create a Transcoder scenario as usual and add a new encoder element. You can watch this tutorial video to see how transcoding scenarios are created.

For custom video codec follow these steps:

Drop video encoder element.
In the "Add output stream" dialog, the "Encoder" dropdown menu must be set to "FFmpeg" value.
In "Codec" field you need to specify the encoder name as defined in video encoder library, e.g. "customvideocodec" in our example. See section 2.2 regarding codec name in build parameters.

Custom audio codec is added the same way:

Drop audio encoder element.
In "Add output stream" dialog, set the "Encoder" field to "FFmpeg".
In Codec field, specify the encoder name as defined in audio encoder library, e.g. "customaudiocodec" in our example. See section 2.2 regarding codec name in build parameters.

Besides that you can specify whatever parameters that are used in your custom encoder.

That's it. Using this technique you may use some third-party libraries which are not yet available in Live Transcoder out-of-the-box.

Also check an example of custom built FFmpeg for NETINT encoder support.

If you have any questions regarding this feature set usage, don't hesitate to contact us and show us your use case.

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