# Wowza VOD with AC3 Audio
**URL:** https://community.wowza.com/t/wowza-vod-with-ac3-audio/49243
**Category:** Wowza Streaming Engine
**Created:** [July 20, 2017, 2:12pm UTC](https://community.wowza.com/t/wowza-vod-with-ac3-audio/49243 "2017-07-20T14:12:11Z")
**Posts on this page:** 3
**Page:** 1
### Author:  [@Brittney\_Shotwell](https://community.wowza.com/u/Brittney_Shotwell)
#### Post date: [July 20, 2017, 2:12pm UTC](https://community.wowza.com/t/wowza-vod-with-ac3-audio/49243/1 "2017-07-20T14:12:11Z")
I’m attempting to play mp4 files that have AC3 audio using Wowza VOD (AC3 is a must for the client). I know that Wowza doesn’t decode the codec, but I have been able to do live streams through Wowza using the AC3 pass through option. (I’m using Wowza 4.2.0.)
Is there a way to use Wowza to play these files out as HLS? This forum post leads me to believe that it is possible, but I have not been able to make it work:
[http://community.wowza.com/community/questions/802/ac3-audio-hiccupsinterruption-at-the-start-of-ever.html](http://community.wowza.com/community/questions/802/ac3-audio-hiccupsinterruption-at-the-start-of-ever.html)
Also, does Wowza only record the audio of incoming streams as AAC? Is there a way to record the incoming stream if it has AC3 audio so that the mp4 file has AC3 audio? This would eliminate the need to record the files I’m wishing to play out via the VOD application using a separate program.
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### Author:  [@Brittney\_Shotwell](https://community.wowza.com/u/Brittney_Shotwell)
#### Post date: [July 24, 2017, 11:14am UTC](https://community.wowza.com/t/wowza-vod-with-ac3-audio/49243/2 "2017-07-24T11:14:22Z")
Hi Alex,
Thanks for the confirmation that AC3 works with VOD. How do I ensure that the Wowza is set to passthrough mode? I can turn on/off the setting for the live application, but I can find no such thing for VOD. Is the audio passthrough a defualt? As for the player and protocol, I am using the same as when I do a livestream, hls to a Roku, so that should not be the issue.
Thanks,
Brittney
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### Author:  [@Brittney\_Shotwell](https://community.wowza.com/u/Brittney_Shotwell)
#### Post date: [July 31, 2017, 3:11pm UTC](https://community.wowza.com/t/wowza-vod-with-ac3-audio/49243/3 "2017-07-31T15:11:01Z")
How exactly do you set the VOD application for passthrough mode? I have been looking, but I have not found where to specify that. Is it a custom property that has to be added?