# changing aspect ratio, GOP size and frame rate

**URL:** <https://community.wowza.com/t/changing-aspect-ratio-gop-size-and-frame-rate/40643>\
**Category:** Wowza Streaming Engine\
**Created:** [July 8, 2013, 1:00am UTC](https://community.wowza.com/t/changing-aspect-ratio-gop-size-and-frame-rate/40643 "2013-07-08T01:00:57Z")\
**Posts on this page:** 4\
**Page:** 1

<div class="post-metadata">

**Author:** ![Manoj\_Prasath](https://avatars.discourse-cdn.com/v4/letter/m/b3f665/32.png) [@Manoj\_Prasath](https://community.wowza.com/u/Manoj_Prasath)\
**Post date:** [July 8, 2013, 1:00am UTC](https://community.wowza.com/t/changing-aspect-ratio-gop-size-and-frame-rate/40643/1 "2013-07-08T01:00:57Z")

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Hi,

I need to change the GOP size and capped VBR of an incoming stream.

Is it possible with WOWZA? If so please let me know the configuration I need to do.

GOP

M frames

N frames

GOP mode

closed GOp

VBR

Min rate

Max rate

Thanks

Manoj

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**Author:** ![sal\_jefferson](https://avatars.discourse-cdn.com/v4/letter/s/6de8d8/32.png) [@sal\_jefferson](https://community.wowza.com/u/sal_jefferson)\
**Post date:** [July 8, 2013, 6:59am UTC](https://community.wowza.com/t/changing-aspect-ratio-gop-size-and-frame-rate/40643/2 "2013-07-08T06:59:20Z")

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Hi Manoj, you will need the Wowza Transcoder for this.

You can set the bitrate and GOP, and create multiple renditions with different bitrates.

Salvadore

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<div class="post-metadata">

**Author:** ![sal\_jefferson](https://avatars.discourse-cdn.com/v4/letter/s/6de8d8/32.png) [@sal\_jefferson](https://community.wowza.com/u/sal_jefferson)\
**Post date:** [July 8, 2013, 7:35am UTC](https://community.wowza.com/t/changing-aspect-ratio-gop-size-and-frame-rate/40643/3 "2013-07-08T07:35:00Z")

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Manoj,

These settings are located in the /transcoder/templates/transrate.xml and transcode.xml files.

You can set frame size:

```auto
<FrameSize>
	<!-- letterbox, fit-width, fit-height, crop, stretch, match-source -->
	<FitMode>fit-height</FitMode>
	<Width>640</Width>
	<Height>360</Height>
	</FrameSize>

```

Key Frame interval:

```auto
<KeyFrameInterval>
	<FollowSource>false</FollowSource>
	<Interval>60</Interval>
	</KeyFrameInterval>

```

And StreamNameGroup for Variable bitrate:

```auto
<StreamNameGroups>
   <!-- Note: Play stream using stream name ngrp:[stream-name] -->
      <StreamNameGroup>
      <Name>all</Name>
      <StreamName>${SourceStreamName}_all</StreamName>
      <Members>
	<Member>
   <EncodeName>source</EncodeName>
	</Member>
	<Member>
	     <EncodeName>720p</EncodeName>
	</Member>
	<Member>
	     <EncodeName>360p</EncodeName>
	</Member>
	<Member>
	     <EncodeName>240p</EncodeName>
	</Member>
	<Member>
	    <EncodeName>160p</EncodeName>
	</Member>
	</Members>
	</StreamNameGroup>
<StreamNameGroup>

```

For more information you can refer to the [Transcoder User Guide](https://www.wowza.com/resources/WowzaTranscoderAddOn_UsersGuide.pdf)

Salvadore

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<div class="post-metadata">

**Author:** ![Manoj\_Prasath](https://avatars.discourse-cdn.com/v4/letter/m/b3f665/32.png) [@Manoj\_Prasath](https://community.wowza.com/u/Manoj_Prasath)\
**Post date:** [July 8, 2013, 5:10am UTC](https://community.wowza.com/t/changing-aspect-ratio-gop-size-and-frame-rate/40643/4 "2013-07-08T05:10:27Z")

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Hi Salvadore,

I have the transcoder Addon too.

But I cant find documentation on how to set GOP and variable bit rates.

Could you please post me a link or a document?

Thanks

Manoj