# HLS Problem
**URL:** https://community.wowza.com/t/hls-problem/39711
**Category:** Wowza Streaming Engine
**Created:** [March 15, 2014, 5:40am UTC](https://community.wowza.com/t/hls-problem/39711 "2014-03-15T05:40:08Z")
**Posts on this page:** 5
**Page:** 1
### Author:  [@Mehrdad\_Armanpour](https://community.wowza.com/u/Mehrdad_Armanpour)
#### Post date: [March 15, 2014, 5:40am UTC](https://community.wowza.com/t/hls-problem/39711/1 "2014-03-15T05:40:08Z")
Hi,
I just recently switched from HDS to HLS, but since then my movie not playing well!
I mean while you’re watching movie unreasonably it moves forward or backward when bit-rate switching happening.
For example, I’m watching movie in 00:00:10, then player decide to play better quality. When bit-rate switching happening, movie goes forward without any reason and start playing the new bit-rate on 00:00:20. Or sometimes it goes back and play from 00:00:05!
Can you please help me with this.
Thanks a lot.
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### Author:  [@Daren\_Johnson](https://community.wowza.com/u/Daren_Johnson)
#### Post date: [March 14, 2014, 9:44pm UTC](https://community.wowza.com/t/hls-problem/39711/2 "2014-03-14T21:44:22Z")
Hi,
What you are describing sounds very much like a key-frame alignment problem between the live streams or vod files (depending whether this is live or vod streaming).
This is how to [troubleshoot keyframe alignment for live](https://www.wowza.com/docs/how-to-debug-encoder-multi-bitrate-keyframe-alignment) streaming:
If you want to troubleshoot vod alignment, you’ll need to go through these steps first, [make multi bitrate vod streams live](https://www.wowza.com/docs/how-to-do-scheduled-adaptive-bitrate-streaming-using-stream-class-streams) while running the debug.
Daren
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### Author:  [@Richard\_Lanham](https://community.wowza.com/u/Richard_Lanham)
#### Post date: [March 16, 2014, 1:00pm UTC](https://community.wowza.com/t/hls-problem/39711/3 "2014-03-16T13:00:56Z")
You need a file encoder that will encode renditions of your stream that are key frame aligned. We have documentation for [Expression 4 Encoder here](https://www.wowza.com/docs/how-to-encode-video-on-demand-content). Note that you need a Expression 4 suite (web or ultimate) to enable the h.264 encoding feature of Expression 4 Encoder.
Richard
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### Author:  [@Zoran](https://community.wowza.com/u/Zoran)
#### Post date: [March 16, 2014, 2:58pm UTC](https://community.wowza.com/t/hls-problem/39711/4 "2014-03-16T14:58:59Z")
Hi,
Yes, you will need to make sure that the VOD files are properly key-frame aligned during the encoding process.
You can take a look at this forum post for an example on how to use FFMPEG to generate properly key-frame aligned VOD files:
> [@Frequently requested FFMPEG command examples for Wowza](http://community.wowza.com/t/-/36326):
>
> Example commands and information for using FFmpeg as a live video/audio encoder with Wowza Media Server. Updated for FFmpeg Build git-a85b4a5 64-bit Static (2012-07-30) Note: Wowza Media Systems provides these instructions on as “AS-IS” basis. FFmpeg is not a Wowza Media Systems product. If you have problems getting FFmpeg to work properly it is best to contact FFmpeg support through their forums or wiki. The information collected here is a brief overview of common FFmpeg solutions. It is int…
Zoran
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### Author:  [@Mehrdad\_Armanpour](https://community.wowza.com/u/Mehrdad_Armanpour)
#### Post date: [March 16, 2014, 12:32pm UTC](https://community.wowza.com/t/hls-problem/39711/5 "2014-03-16T12:32:14Z")
Thanks for your reply.
So, how can I perform the key-frame alignment in each VoD stream?
Is it some kind of configuration on the streaming side? Or I have to do the key-frame alignment when I’m encoding things?
Thanks a lot.