Wowza Community

Transcode multiple audio channels and split each stereo pair (left/right) into two mono channels

Hello Community!

We are providing a UDP Stream with multiple audio channels (8 channel pairs = 16 mono channels) and we want to transcode one video with multiple audio channels (ex. english, german, italian and 13 more). Our question is: There are multiple audioIDs (from 36 to 43, which means these are pairs with two mono channels. We want to extract the mono channels from each pair and transcode them, because we only need the mono channels. Is this possible?

If yes, do you know and can you help us to realize that?

If no, then we need more audio channel pairs (not 8 --> 16) and we have read the article: https://www.wowza.com/docs/how-to-specify-per-stream-settings-in-stream-files and https://www.wowza.com/docs/how-to-use-alternative-audio-or-video-tracks-with-apple-hls-streams which way is better? And how does it work perfectly?

For now: **1.) I just created an application named “live” nothing else special is configured.**2.) I created a Stream File: A udp-stream coming from a public ip with port 10000 and I add some parameters (where AudioPID 37 = english).

3.) I “Connect to the stream” and then the engine list me the “incoming streams”.

Now the final questions are:

a.) Should I create more applications for each language?

b.) Can I copy the Stream Files, set the parameters for each language and then connect all Stream Files?

c.) And/or should I work with the transcoder templates and if yes, how I realize that?

Can someone help us please?

Many Thx,

Rob

Hey Robin sounds like a great workflow and I do have some advice for you:

You’re on the right track with creating separate .stream files with each referencing a different audio pid. And then use that info in the alternative tracks article to tie them all together for playback.

The article shows how to use a separate startup smil file to make sure all streams start at the same time.

If the audio is already the right format then there’s probably no need to transcode.

unless you want different video renditions.

As far as Engine: Transcode multiple audio channels and split each stereo pair (left/right) into two mono channels.

Looks like it can be done on the encode side of the transcoder. Two encodes, one for left & one for right.

You can see this post for reference:

https://www.wowza.com/community/questions/1943/transcode-audioleftright-channels-to-two-mono-stre.html

If you still need a hand, please feel free to submit a support ticket to us and the engineers can walk you through it.

Thank you!

Thank you for the advise!

It was very helpful! Thank you!!

Glad it helped you out! :slight_smile:

Sorry for the pedantic question. I am new in the process and still going through the article you have usefully shared. I am trying to understand the rationale but I wanted to make sure I could stream one video + 5 audio channels using my encoder Epiphan Pearl2. The point is that from the Epiphan I have to launch one streaming flow for each language channel, which translates into several applications on the Wowza Engine side, it’s not easy for me to understand how the smil will group all these flows together. We use HLS protocol. thank you and sorry for the confusion.

That’s ok, it’s actually considered a more advanced workflow. We do have the article on how to have multiple audio tracks for one video stream over HLS here.

https://www.wowza.com/docs/how-to-use-alternative-audio-or-video-tracks-with-apple-hls-streams

As far at that Epiphan Pearl2 encoder, I believe the only requirement is to have the timecodes aligned per the article.

I strongly advise you to submit a ticket so an engineer can walk through this with you. That’s what we’re here to do, help with configurations and it could save you a lot of time potentially. Hope it gets running successfully for you soon!