# CentOS vs Windows - Quicksync video quality **URL:** \ **Category:** Wowza Streaming Engine\ **Created:** [December 14, 2012, 3:29pm UTC](https://community.wowza.com/t/centos-vs-windows-quicksync-video-quality/35760 "2012-12-14T15:29:19Z")\ **Posts on this page:** 4\ **Page:** 1
**Author:** ![Matthew\_Vinson](https://avatars.discourse-cdn.com/v4/letter/m/eb9ed0/32.png) [@Matthew\_Vinson](https://community.wowza.com/u/Matthew_Vinson)\ **Post date:** [December 14, 2012, 3:29pm UTC](https://community.wowza.com/t/centos-vs-windows-quicksync-video-quality/35760/1 "2012-12-14T15:29:19Z")
We recently switched our server to CentOS with QuickSync built from source per the Wowza 3.5 instructions and have noticed a considerable shift in quality of the resulting streams. While our Windows server was able to deliver near flawless transcodes of 4 HD streams the new CentOS server has severe banding and artifacting in large color fields. The quality is very poor in comparison to the Windows QuickSync experience. Do you have any suggestions for improving stream quality on Linux? ---
**Author:** ![Charlie\_Good](https://sea2.discourse-cdn.com/flex002/user_avatar/community.wowza.com/charlie_good/32/383_2.png) [@Charlie\_Good](https://community.wowza.com/u/Charlie_Good)\ **Post date:** [December 14, 2012, 3:47pm UTC](https://community.wowza.com/t/centos-vs-windows-quicksync-video-quality/35760/2 "2012-12-14T15:47:30Z")
The current instructions are pointing to the staging source depot of the Intel VPP library. At the time of writing of the article this depot contained the first cut of the source code that included support for the main profile. I believe this version of the code has been released and there is a chance the staging area now contains new code that is less stable. I am working on revising instructions for the updated source code. I will report back when I have a more stable build process. Can you provide a sample of the bad looking stream? If possible please send a URL to support@wowza.com and reference this forum thread. Charlie ---
**Author:** ![Charlie\_Good](https://sea2.discourse-cdn.com/flex002/user_avatar/community.wowza.com/charlie_good/32/383_2.png) [@Charlie\_Good](https://community.wowza.com/u/Charlie_Good)\ **Post date:** [December 15, 2012, 7:34am UTC](https://community.wowza.com/t/centos-vs-windows-quicksync-video-quality/35760/3 "2012-12-15T07:34:28Z")
I did investigate this a bit more today and it looks like the most recent stable release from Intel still does not include support for main profile video encoding ([http://intellinuxgraphics.org/2012Q4.html](http://intellinuxgraphics.org/2012Q4.html)). So I do not have an improved set of instructions at this time. I really am not sure when main profile support will be included in a stable release build from Intel. Hopefully it will show up in the next drop. Charlie ---
**Author:** ![Matthew\_Vinson](https://avatars.discourse-cdn.com/v4/letter/m/eb9ed0/32.png) [@Matthew\_Vinson](https://community.wowza.com/u/Matthew_Vinson)\ **Post date:** [December 20, 2012, 11:30am UTC](https://community.wowza.com/t/centos-vs-windows-quicksync-video-quality/35760/4 "2012-12-20T11:30:47Z")
The banding and artifacts do not seem as bad in the last few days. I rebuilt the Main Profile QuickSync libraries per the Wowza article after I noticed they weren’t available after a reboot. Is there a specific way to start the server to ensure that the QuickSync loads properly? What is the best way to set up the server for restarting Wowza with QuickSync after a reboot? I tried to send you a private message with one of our streams, the quality is definitely better than the first day or two with QuickSync on Linux but I am still encountering banding and artifact issues with large color fields. It seems you have no space for private messages… and we can’t publicly list the feed.