# Is this an appropriate use of the transcoder? If not, alternative method?

**URL:** <https://community.wowza.com/t/is-this-an-appropriate-use-of-the-transcoder-if-not-alternative-method/46419>\
**Category:** Wowza Streaming Engine\
**Created:** [December 27, 2015, 6:23pm UTC](https://community.wowza.com/t/is-this-an-appropriate-use-of-the-transcoder-if-not-alternative-method/46419 "2015-12-27T18:23:18Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![aaaaa\_cccccc](https://avatars.discourse-cdn.com/v4/letter/a/3ab097/32.png) [@aaaaa\_cccccc](https://community.wowza.com/u/aaaaa_cccccc)\
**Post date:** [December 27, 2015, 6:23pm UTC](https://community.wowza.com/t/is-this-an-appropriate-use-of-the-transcoder-if-not-alternative-method/46419/1 "2015-12-27T18:23:18Z")

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My goal was to retrieve a preview thumbnail image of a live stream in progress. After some research, I found [a method](https://www.wowza.com/docs/how-to-get-thumbnail-images-from-wowza-transcoder-with-an-http-provider). After enabling the transcoder, I set the audio and video to ‘passthrough’, but that doesn’t work; an encoding (240p, 480p…) must be selected for the transcoder to yield a thumbnail. I chose the option that matches the broadcast. It works, I get the preview thumbnails, but my concern is the CPU overhead incurred as a result of the transcoder running. Is this approach recommended? If not, what other route can I take?

Although I have found other solutions, they were in outdated threads and, frankly, hackish.

[https://www.wowza.com/docs/how-to-take-a-single-frame-snapshot-of-a-live-stream-for-thumbnail-creation-modulecreatesnapshot](https://www.wowza.com/docs/how-to-take-a-single-frame-snapshot-of-a-live-stream-for-thumbnail-creation-modulecreatesnapshot)

> [@Custom module to create single frame snapshots of live and VOD stream](http://community.wowza.com/t/-/38):
>
> Below is a sample Wowza Pro custom module to create a single key frame .flv file (snapshot) of either a live or video on demand stream. To use this code, download and install the Wowza Pro IDE and follow the instructions in the included User’s Guide. package com.wowza.wms.plugin.test.module; import java.io.\*; import com.wowza.util.\*; import com.wowza.wms.module.\*; import com.wowza.wms.amf.\*; import com.wowza.wms.application.\*; import com.wowza.wms.client.IClient; import com.wowza.wms.stream.\*…

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**Author:** ![Michelle\_B](https://sea2.discourse-cdn.com/flex002/user_avatar/community.wowza.com/michelle_b/32/394_2.png) [@Michelle\_B](https://community.wowza.com/u/Michelle_B)\
**Post date:** [December 30, 2015, 5:18pm UTC](https://community.wowza.com/t/is-this-an-appropriate-use-of-the-transcoder-if-not-alternative-method/46419/2 "2015-12-30T17:18:54Z")

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Hi,

In order to retrieve a frame from a live stream, it would need to be decoded by Wowza, which requires enabling the Transcoder. A passthru rendition does not trigger the transcoder, but specifying an output rendition would. The downside, unfortunately, is the load on your CPU. The alternative to getting a thumbnail frame without a transcoder are the ones you have found already, which essentially grabs a single-frame recording of the live stream. If you find that you are using a more than 60% of your CPU resources using transcoding, you may want to consider going through the alternative route instead.

Michelle