# Live Streaming of Audio Only starting with RTP/PCMA **URL:** \ **Category:** Wowza Streaming Engine\ **Created:** [May 21, 2013, 11:09am UTC](https://community.wowza.com/t/live-streaming-of-audio-only-starting-with-rtp-pcma/40468 "2013-05-21T11:09:24Z")\ **Posts on this page:** 5\ **Page:** 1
**Author:** ![Wesley\_Miller](https://avatars.discourse-cdn.com/v4/letter/w/71c47a/32.png) [@Wesley\_Miller](https://community.wowza.com/u/Wesley_Miller)\ **Post date:** [May 21, 2013, 11:09am UTC](https://community.wowza.com/t/live-streaming-of-audio-only-starting-with-rtp-pcma/40468/1 "2013-05-21T11:09:24Z")
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 ---
**Author:** ![Richard\_Lanham](https://avatars.discourse-cdn.com/v4/letter/r/c68b51/32.png) [@Richard\_Lanham](https://community.wowza.com/u/Richard_Lanham)\ **Post date:** [May 22, 2013, 2:07pm UTC](https://community.wowza.com/t/live-streaming-of-audio-only-starting-with-rtp-pcma/40468/2 "2013-05-22T14:07:32Z")
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](https://www.wowza.com/docs/how-to-publish-and-play-a-live-stream-mpeg-ts-based-encoder) Is the audio [G.711](http://en.wikipedia.org/wiki/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](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 ---
**Author:** ![Richard\_Lanham](https://avatars.discourse-cdn.com/v4/letter/r/c68b51/32.png) [@Richard\_Lanham](https://community.wowza.com/u/Richard_Lanham)\ **Post date:** [May 22, 2013, 3:19pm UTC](https://community.wowza.com/t/live-streaming-of-audio-only-starting-with-rtp-pcma/40468/3 "2013-05-22T15:19:56Z")
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](https://www.wowza.com/docs/how-to-debug-push-publishing) Richard ---
**Author:** ![Richard\_Lanham](https://avatars.discourse-cdn.com/v4/letter/r/c68b51/32.png) [@Richard\_Lanham](https://community.wowza.com/u/Richard_Lanham)\ **Post date:** [May 23, 2013, 1:43am UTC](https://community.wowza.com/t/live-streaming-of-audio-only-starting-with-rtp-pcma/40468/4 "2013-05-23T01:43:21Z")
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](https://www.wowza.com/docs/how-to-use-vlc-as-a-live-stream-encoder-with-wowza-media-server-mpeg-ts) Richard ---
**Author:** ![Wesley\_Miller](https://avatars.discourse-cdn.com/v4/letter/w/71c47a/32.png) [@Wesley\_Miller](https://community.wowza.com/u/Wesley_Miller)\ **Post date:** [May 22, 2013, 9:55am UTC](https://community.wowza.com/t/live-streaming-of-audio-only-starting-with-rtp-pcma/40468/5 "2013-05-22T09:55:40Z")
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](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](http://en.wikipedia.org/wiki/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](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 > > Yes. It is from the Gstreamer alawenc encoder. The [alawenc](http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gst-plugins-good-plugins/html/gst-plugins-good-plugins-alawenc.html) webpage says: > > > alawenc — Convert 16bit PCM to 8bit A law > > > > Description > > > > This element encode alaw audio. Alaw coding is also known as G.711.