# resolveStreamAlias not called for MediaCaster stream

**URL:** <https://community.wowza.com/t/resolvestreamalias-not-called-for-mediacaster-stream/102247>\
**Category:** Wowza Developer Dojo\
**Created:** [October 30, 2024, 7:19pm UTC](https://community.wowza.com/t/resolvestreamalias-not-called-for-mediacaster-stream/102247 "2024-10-30T19:19:26Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![Andrew\_O\_Hara](https://avatars.discourse-cdn.com/v4/letter/a/c5a1d2/32.png) [@Andrew\_O\_Hara](https://community.wowza.com/u/Andrew_O_Hara)\
**Post date:** [October 30, 2024, 7:19pm UTC](https://community.wowza.com/t/resolvestreamalias-not-called-for-mediacaster-stream/102247/1 "2024-10-30T19:19:26Z")

</div>

**Background**

I have two wowza apps:`rtp` and `rtp-cr`. Both of them use the `MediaCaster` API and rely on a `IMediaStreamNameAliasProvider3` to resolve a stream alias. Both apps have unique custom java modules; each of which overrides `onAppStart` to call `setStreamNameAliasProvider`. There are some differences between them:

1. `rtp-cr` is for recording 24/7 streams and has historically used stream files to save static RTSP URIs
2. `rtp` starts streams on demand, and terminates them after a few minutes. Streams are started exclusively via the mediaCaster API

We’re on Wowza version 4.8.28. We can’t upgrade due to outstanding issues in future wowza versions that break certain devices.

**Problem**

We now have some devices with dynamic RTSP URIs, so `rtp-cr` cannot rely on static stream files for these devices. Instead, we’ll have a daemon start the stream with the MediaCaster API, and rely on stream aliasing to resolve the device URI.

In practice, the `rtp` app calls `resolvePlayAlias` and `resolveStreamAlias` as expected. But the the`rtp-cr` app only calls `resolvePlayAlias`. So when I used the Media Caster API to start a stream for `rtp-cr`, I end up with an `Incoming Stream` stuck in the `Waiting For Stream` state. This is the problem I’m trying to solve.

**Analysis**

Here are the relevant logs when starting a stream on each app:

```auto
# rtp-cr
2024-10-30 17:33:41 UTC INFO -> 200 ApplicationInstance.startMediaCasterStream[rtp-cr/_definst_]: Stream started: mp4:device1 - - - 5.848
2024-10-30 17:33:41 UTC INFO -> 200 RTPMediaCaster.Reconnector[1964503668:rtp-cr/_definst_:device1]: start: 1 - - - 5.853
2024-10-30 17:33:41 UTC INFO -> 200 RTPSessionDescriptionDataProviderBasic.getStreamInfo[rtp-cr/_definst_]: /usr/local/WowzaStreamingEngine/content/device1 - - - 5.954
2024-10-30 17:33:41 UTC WARN -> 200 RTPSessionDescriptionDataProviderBasic.getStreamInfo: SDP file missing: /usr/local/WowzaStreamingEngine/content/device1 - - - 5.954

# rtp
2024-10-30 17:26:48 UTC INFO -> 200 ApplicationInstance.startMediaCasterStream[rtp/_definst_]: Stream started: mp4:device1 - - - 1956.056
2024-10-30 17:26:48 UTC INFO -> 200 StreamNameAliasProvider.resolveStreamAlias: device1 -> rtsp://<url> - - - 1956.156  

```

The logs suggest that `rtp-cr` is trying and failing to look up the stream URI from a nonexistent stream file.  
This isn’t surprising, since that was the intended workflow up until now. But if it’s causing trouble, then how can I avoid that lookup for specific streams?

**Unsatisfactory Workaround**

One workaround I’ve tried is to resolve the RTSP URI before invoking the mediaCaster API, but this results in an `Incoming Stream` with a name that matches the URI. This is not ideal; we’d like the stream name to be the device id, for debugging purposes. If there was a Media Caster method allowing us to set the stream name and URI independently, this could work.

The decompiled wms jars show an undocumented `startMediaCasterStream` operation that accepts an additional String argument. I had hoped this was a stream name, but trial and error show it seems to be a port.

`boolean startMediaCasterStream(String var1, String var2, String var3);`

**Conclusion**

I’m hoping someone can help me understand what factors and configuration settings may lead to `resolveStreamAlias` not being called for this one app. Unfortunately, there’s a lot of code, which can’t be easily shared.

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<div class="post-metadata">

**Author:** ![Andrew\_O\_Hara](https://avatars.discourse-cdn.com/v4/letter/a/c5a1d2/32.png) [@Andrew\_O\_Hara](https://community.wowza.com/u/Andrew_O_Hara)\
**Post date:** [November 6, 2024, 2:19pm UTC](https://community.wowza.com/t/resolvestreamalias-not-called-for-mediacaster-stream/102247/2 "2024-11-06T14:19:51Z")

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Since no one was able to assist, I had to make a duplicate Wowza application to handle this new workflow. As far as I can tell, they have identical configurations, but the new app works as you’d expect.