# ?Transrate a transcode audio only?

**URL:** <https://community.wowza.com/t/transrate-a-transcode-audio-only/50557>\
**Category:** Wowza Streaming Engine\
**Tags:** transcoder\
**Created:** [January 12, 2018, 10:48pm UTC](https://community.wowza.com/t/transrate-a-transcode-audio-only/50557 "2018-01-12T22:48:15Z")\
**Posts on this page:** 6\
**Page:** 1

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**Author:** ![Jeffrey\_Snell](https://avatars.discourse-cdn.com/v4/letter/j/ba9def/32.png) [@Jeffrey\_Snell](https://community.wowza.com/u/Jeffrey_Snell)\
**Post date:** [January 12, 2018, 10:48pm UTC](https://community.wowza.com/t/transrate-a-transcode-audio-only/50557/1 "2018-01-12T22:48:15Z")

</div>

I need to be able to take a single, high quality ,audio only, mp3 stream . . . convert it to ACC and create several different rates for an HLS audio stream Is this possible using Wowza Transcoder?

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<div class="post-metadata">

**Author:** ![system](https://sea2.discourse-cdn.com/flex002/user_avatar/community.wowza.com/system/32/447_2.png) [@system](https://community.wowza.com/u/system)\
**Post date:** [January 12, 2018, 10:59pm UTC](https://community.wowza.com/t/transrate-a-transcode-audio-only/50557/2 "2018-01-12T22:59:34Z")

</div>

We have an article on how to deliver an audio only stream using Transcoder. You can add different bitrates as appropriate to your audio only Transcoder template.

[https://www.wowza.com/docs/how-to-transcode-only-the-audio-channel-of-an-incoming-stream](https://www.wowza.com/docs/how-to-transcode-only-the-audio-channel-of-an-incoming-stream)

Please make sure that you follow the instructions in the article below to have audio only HLS content to be played back.

[https://www.wowza.com/docs/how-to-configure-wowza-server-to-stream-audio-only-apple-hls-using-transport-stream](https://www.wowza.com/docs/how-to-configure-wowza-server-to-stream-audio-only-apple-hls-using-transport-stream)

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<div class="post-metadata">

**Author:** ![Jeffrey\_Snell](https://avatars.discourse-cdn.com/v4/letter/j/ba9def/32.png) [@Jeffrey\_Snell](https://community.wowza.com/u/Jeffrey_Snell)\
**Post date:** [January 12, 2018, 11:21pm UTC](https://community.wowza.com/t/transrate-a-transcode-audio-only/50557/3 "2018-01-12T23:21:09Z")

</div>

I have followed that article (and am able to transcode the file) but how do I take that newly transcoded audio and make three lower bit rate streams that can then be bound up in a SMIL file for HLS?

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<div class="post-metadata">

**Author:** ![system](https://sea2.discourse-cdn.com/flex002/user_avatar/community.wowza.com/system/32/447_2.png) [@system](https://community.wowza.com/u/system)\
**Post date:** [January 12, 2018, 11:45pm UTC](https://community.wowza.com/t/transrate-a-transcode-audio-only/50557/4 "2018-01-12T23:45:17Z")

</div>

Below is an audio only Transcoder template I just created that disables all video conversion and converts the audio to AAC at 48Kbps, 64Kbps, 128Kbps, and 192Kbps.

It was created via Wowza Streaming Engine Manager / live / Transcoder / Add Template after copying the audio stream name from the “Audio Only (Default)” template.

As I created each audio rendition I made sure to disable video and change audio from passthrough to AAC.

```auto
<?xml version="1.0" encoding="UTF-8"?>
<Root>
    <Transcode>
        <Description></Description>
        <Decode>
            <Video>
                <Implementation>default</Implementation>
                <Deinterlace>false</Deinterlace>
            </Video>
        </Decode>
        <Encodes>
            <Encode>
                <Name>48K</Name>
                <Enable>true</Enable>
                <Description></Description>
                <StreamName>mp4:${SourceStreamName}_48k_aac</StreamName>
                <Video>
                    <Codec>Disable</Codec>
                    <Implementation></Implementation>
                    <GPUID>-1</GPUID>
                    <Profile></Profile>
                    <Bitrate>0</Bitrate>
                    <KeyFrameInterval>
                        <FollowSource>false</FollowSource>
                        <Interval>0</Interval>
                    </KeyFrameInterval>
                    <FrameSize>
                        <FitMode></FitMode>
                        <Width>0</Width>
                        <Height>0</Height>
                        <Crop></Crop>
                        <SourceRectangle></SourceRectangle>
                    </FrameSize>
                </Video>
                <Audio>
                    <Codec>AAC</Codec>
                    <Bitrate>48000</Bitrate>
                </Audio>
            </Encode>
            <Encode>
                <Name>64k</Name>
                <Enable>true</Enable>
                <Description></Description>
                <StreamName>mp4:${SourceStreamName}_64k_aac</StreamName>
                <Video>
                    <Codec>Disable</Codec>
                    <Implementation></Implementation>
                    <GPUID>-1</GPUID>
                    <Profile></Profile>
                    <Bitrate>0</Bitrate>
                    <KeyFrameInterval>
                        <FollowSource>false</FollowSource>
                        <Interval>0</Interval>
                    </KeyFrameInterval>
                    <FrameSize>
                        <FitMode></FitMode>
                        <Width>0</Width>
                        <Height>0</Height>
                        <Crop></Crop>
                        <SourceRectangle></SourceRectangle>
                    </FrameSize>
                </Video>
                <Audio>
                    <Codec>AAC</Codec>
                    <Bitrate>64000</Bitrate>
                </Audio>
            </Encode>
            <Encode>
                <Name>128k</Name>
                <Enable>true</Enable>
                <Description></Description>
                <StreamName>mp4:${SourceStreamName}_128k_aac</StreamName>
                <Video>
                    <Codec>Disable</Codec>
                    <Implementation></Implementation>
                    <GPUID>-1</GPUID>
                    <Profile></Profile>
                    <Bitrate>0</Bitrate>
                    <KeyFrameInterval>
                        <FollowSource>false</FollowSource>
                        <Interval>0</Interval>
                    </KeyFrameInterval>
                    <FrameSize>
                        <FitMode></FitMode>
                        <Width>0</Width>
                        <Height>0</Height>
                        <Crop></Crop>
                        <SourceRectangle></SourceRectangle>
                    </FrameSize>
                </Video>
                <Audio>
                    <Codec>AAC</Codec>
                    <Bitrate>128000</Bitrate>
                </Audio>
            </Encode>
            <Encode>
                <Name>192K</Name>
                <Enable>true</Enable>
                <Description></Description>
                <StreamName>mp4:${SourceStreamName}_192k_aac</StreamName>
                <Video>
                    <Codec>Disable</Codec>
                    <Implementation></Implementation>
                    <GPUID>-1</GPUID>
                    <Profile></Profile>
                    <Bitrate>0</Bitrate>
                    <KeyFrameInterval>
                        <FollowSource>false</FollowSource>
                        <Interval>0</Interval>
                    </KeyFrameInterval>
                    <FrameSize>
                        <FitMode></FitMode>
                        <Width>0</Width>
                        <Height>0</Height>
                        <Crop></Crop>
                        <SourceRectangle></SourceRectangle>
                    </FrameSize>
                </Video>
                <Audio>
                    <Codec>AAC</Codec>
                    <Bitrate>192000</Bitrate>
                </Audio>
            </Encode>
        </Encodes>
    </Transcode>
</Root>

```

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<div class="post-metadata">

**Author:** ![Jeffrey\_Snell](https://avatars.discourse-cdn.com/v4/letter/j/ba9def/32.png) [@Jeffrey\_Snell](https://community.wowza.com/u/Jeffrey_Snell)\
**Post date:** [January 18, 2018, 6:50pm UTC](https://community.wowza.com/t/transrate-a-transcode-audio-only/50557/5 "2018-01-18T18:50:00Z")

</div>

Brilliant, Thanks Kevin. Works like a charm.

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<div class="post-metadata">

**Author:** ![system](https://sea2.discourse-cdn.com/flex002/user_avatar/community.wowza.com/system/32/447_2.png) [@system](https://community.wowza.com/u/system)\
**Post date:** [January 19, 2018, 2:21am UTC](https://community.wowza.com/t/transrate-a-transcode-audio-only/50557/6 "2018-01-19T02:21:11Z")

</div>

You will need to install the MultiTrackVOD module to switch between audio tracks when video is included.

[https://www.wowza.com/docs/how-to-select-multiple-tracks-from-a-vod-file-modulemultitrackvod](https://www.wowza.com/docs/how-to-select-multiple-tracks-from-a-vod-file-modulemultitrackvod)

Apple HLS:

[https://www.wowza.com/docs/how-to-use-alternative-audio-or-video-tracks-with-apple-hls-streams#vodsmil](https://www.wowza.com/docs/how-to-use-alternative-audio-or-video-tracks-with-apple-hls-streams#vodsmil)

MPEG-DASH:

[https://www.wowza.com/docs/how-to-use-alternative-audio-or-video-tracks-with-mpeg-dash-streams#vodselective](https://www.wowza.com/docs/how-to-use-alternative-audio-or-video-tracks-with-mpeg-dash-streams#vodselective)