September 5, 2019

Larix Screencaster for iOS - live streaming from any app

Softvelum provides a number of solutions for mobile streaming and playback.

Today we introduce Larix Screencaster for iOS.

Larix Screencaster application allows capturing the content of user device and streaming it to the target media server or service. The list of supported protocols includes RTMP/RTMPS, RTSP/RTSPS and SRT, you can stream AVC/H.264 and HEVC/H.265.

Install Larix Screencaster here.

The setup of streaming is similar to Larix Broadcaster, you can read documentation reference for connectivity details.

As for the screen recording part, Apple requires additional setup:

Please study these sources to perform the setup.

Let us know if you have any questions regarding Larix Screencaster or other mobile solutions.

September 4, 2019

Generating Icecast metadata from RTMP

Nimble Streamer can re-package incoming RTMP stream into outgoing Icecast stream, it's part of our extensive audio streaming feature set.
RTMP protocol has the ability to carry Icecast metadata and encoders like Omnia Z/IPStream X/2StreamS Live Legacy Encoder and some others may produce this kind of streams.
So Nimble Streamer can pass that metadata from RTMP input to Icecast output.

If you need to process the input RTMP Icecast metadata for further use in Icecast, you need to enable this capability on server or per-application level. If you want to pass the RTMP Icecast metadata through Live Transcoder, you also need to enable it.

To enable the feature globally for entire server, go to Nimble Streamer / Live streams settings menu to open the setup page and choose the required server from the drop-down list. By default, the Global tab will be opened. Here you need to select Icecast protocol to have it in the output. This will show Generate Icecast metadata checkbox which you also need to select as shown below.

If you'd like to define this separately for specific application then choose Applications tab. Click on existing application's settings or click on Add application settings button to create a new one. Its settings will be similar to those described above so you need to select Icecast among protocols and click Generate Icecast metadata checkbox.

Once you save settings and re-start your input RTMP stream, the streams in the affected applications will have the Icecast metadata. You can use it as part of Icecast streaming or for passing through Transcoder scenarios.

Notice that RTMP output streams will have the Icecast metadata regardless or the described setting. This means that if you re-publish such RTMP stream or make it available for further pulled, it will have the Icecast metadata. However if you decide to transcode the stream and keep the Icecast metadata, you'll have to follow this setup process.

Contact us if you have any questions regarding any of our features.

Related documentation

Live Transcoder for Nimble StreamerAudio streaming feature setRTMP support

Forwarding RTMP Icecast metadata through Live Transcoder

RTMP protocol has the ability to carry Icecast metadata. Nimble Streamer can forward that metadata into output stream when transmuxing from RTMP to Icecast. However some scenarios may require Live Transcoder to be involved in order to transform audio. In this case the metadata from RTMP stream need to be carried through the transcoder pipeline by setting parameters in a transcoding scenario. Let's see how this can be done.

Notice that Nimble Live Transcoder is able to passthrough the Icecast metadata. Please make appropriate setup for respective protocol use case. 
If you have incoming Icecast with Icecast metadata, please follow this instruction and skip this article.
If you have incoming RTMP with Icecast metadata, you need to follow the instruction below.

Enable RTMP Icecast metadata

First, the incoming stream must have the RTMP Icecast metadata delivered. So you need to enable RTMP Icecast metadata processing as described in this article. If you don't set up the designated application or entire server processing the RTMP Icecast metadata, it will not be available for transcoder scenarios.

Set up Transcoder

In this sample scenario we use transcoder for re-sampling audio from the existing RTMP stream. You may see a decoder, then a filter to perform sampling and then an encoder.

The forwarding needs to be specified on both decoder and encoder sides. In the audio decoder element you need to check the Forward RTMP metadata checkbox to set the transcoder to take metadata into the pipeline.

Now go to video encoder element and click on Expert setup.

Here you need to check the Forward RTMP metadata checkbox to make the transcoder grab the metadata from the pipeline and make it part of output stream.

Once you save the scenario and re-start the input stream, the output stream will have the metadata which then can be used for transmuxing into Icecast or re-publishing.

Contact us if you have any questions regarding any of our features.

Related documentation

Live Transcoder for Nimble StreamerAudio streaming feature setRTMP support

September 3, 2019

Processing DVB subtitles in Nimble Streamer and Transcoder

DVB (Digital Video Broadcasting) subtitles are used for media streaming from various sources via MPEG2TS and HLS. Nimble Streamer allows transferring DVB subtitles from incoming streams to its output.

Enable the DVB subtitles processing for MPEG2TS and HLS streams

If your incoming MPEG2TS or HLS stream has DVB subtitles and you need to have those subtitles to be passed through to output MPEG-TS and HLS, you need to add the following parameter into your Nimble config:
dvb_subtitles_processing_enabled = true
Once you add it and re-start Nimble Streamer, your output HLS and MPEG-TS will have DVB subtitles if your source streams have them.

Passing DVB subtitles through Live Transcoder

If you need to transcode your streams (e.g. make multiple resolutions or put graphics on top) and keep DVB subtitles from the source stream, you'll need to make some additional changes to your transcoding scenarios. Also notice that you must have dvb_subtitles_processing_enabled parameter to be enabled as described above.

Let's take a look at a simple scenario which allows keeping original stream as well as make lower resolutions.

Here you see /live/source stream being processed to get /live/output_480p output stream down-scaled to 480p (via Scale filter box) and keep the original rendition as /live/output_original stream.

There are 2 ways of passing the DVB - via video and via audio pipeline. We'll demonstrate both ways.

The /live/output_original stream has video being passed through - you can see long line with blue-to-orange gradient. This way, if you have full HD stream as input, you won't waste resources decoding and encoding the content to the same rendition. But the audio is split to decoder and encoder. Let's see their settings.


In the source stream decoder you see the enabled Forward DVB subtitles checkbox. It enables the transcoder to grab the subtitles for processing. In audio encoder setting, you click on Expert setup section to see the Forward DVB subtitles checkbox again. Check it to make the encoder take the subtitles which were previously grabbed into the pipeline by the decoder. After saving the transcoder scenario and re-starting the incoming stream, the output will have the DVB subtitles in the result stream.

The /live/output_480p stream has audio being passed through while video is transformed to lower rendition. So here we use video pipeline to pass DVB subtitles. It's set up the same way - both in decoder and encoder elements.

You need to check Forward DVB subtitles checkbox in video decoder and in video encoder settings under Expert setup section. As in case of audio, once you save the scenario and re-start input stream, the output will have the initial DVB subtitles.

Related documentation

Live TranscoderMPEG2TS streamingHLS streaming