Live Streaming of Audio Only starting with RTP/PCMA

Wowza Streaming Engine
1

First, please forgive me for being a newbie and for possibly posting in the wrong place. This forum was the best guess I came up with.

I currently have a sender receiver pair coded to send audio only between two endpoints, as in an intercom. My encoding is non-wowza-standard; it is live microphone -> PCMA encode -> RTP payload -> UDP which is decoded on the other end as UDP -> RTP depayload ->PCMA decode -> speakers. The code is a Gstreamer pipeline on both ends. FWIW, I chose PCMA because all the applications that use it are LGPL. None of that nasty GPL virus!

As far as I can tell, I could send this to Wowza (+ transcoder???) and the output stream would be converted to RTSP and AAC. Sadly, the Gstreamer FAAD AAC decoder is GPL and I am pretty much forbidden to use any GPL product.

So, to get me started,

WHich application should I go with: Live streaming and comment out the camera XML configuration? Transcoder and disable video (HOW?)

Is there a way to have Wowza use my encoded stream?

Thanks for any help. I’m not having much luck getting started and a leg up will be a big help. – Wes

2

Hi, welcome,

First, follow the mpeg-ts tutorial to re-stream the udp:

https://www.wowza.com/docs/how-to-publish-and-play-a-live-stream-mpeg-ts-based-encoder

Is the audio G.711?. If so, you can use the Wowza Transcoder which will transcode to AAC. The transcoded stream can be played back on rtsp and rtmp clients, and HLS, HDS and Smooth http clients.

https://www.wowza.com/docs/how-to-set-up-and-run-wowza-transcoder-for-live-streaming

Use the /transcoder/templates/AudioOnly.xml template, but change the /Encode /Video /Codec to “Disable”

Richard

3

Playback clients will use rtmp, rtsp or one of http streamtypes. If you want udp out, you can use the PushPublish addon

https://www.wowza.com/docs/how-to-debug-push-publishing

Richard

4

Take a look at VLC for a test sender:

https://www.wowza.com/docs/how-to-use-vlc-as-a-live-stream-encoder-with-wowza-media-server-mpeg-ts

Richard

5

Richard,

Thank you for the starting point. Will head there straight away.

First a follow up question:

First, follow the mpeg-ts tutorial to re-stream the udp:

https://www.wowza.com/forums/content…based-encoder)

Does this mean the UDP will be restreamed as UDP or the RTP/PCMA inside will be extracted, converted and the whole lot restreamed as some other stgream type? RTSP/RTMP/etc.

And to answer your question:

Is the audio G.711?. If so, you can use the Wowza Transcoder which will transcode to AAC. The transcoded stream can be played back on rtsp and rtmp clients, and HLS, HDS and Smooth http clients.

Set up and run Transcoder for live streaming

Use the /transcoder/templates/AudioOnly.xml template, but change the /Encode /Video /Codec to “Disable”

Richard

Yes. It is from the Gstreamer alawenc encoder. The alawenc webpage says:

alawenc — Convert 16bit PCM to 8bit A law

Description

This element encode alaw audio. Alaw coding is also known as G.711.