MediaPortal Wiki > MediaPortal 1 > Support > Troubleshooting > Stuttering Playback

Stuttering Playback

    Table of Contents

    Author: Te3hpurp

    Created: Jul 4, 2010

    Updated: Jan 20, 2013


    This guide is written to help users solve playback problems on their own. It is not possible to cover every system, however the guide provides an overview of what things might affect playback quality. There is also a very detailed and complete guide in AVS forum for building HTPC.

    Please remember that recommendations in that guide are slighly off for Mediaportal, because of the way Mediaportal handles Graphical User Interface. Mediaportal GUI requires more GPU power than for example DVBViewer.


    At first we should make ourselves familiar with some of the terms that are often used in Team MediaPortal forums.


    Integrated GPU, meaning display adapter is integrated  into motherboard.


    Means that video freezes for a short period of time. This can happen for a number of reasons.


    Means that there is thin line that cuts screen and upper and lower parts are drifted apart. In most cases this is because wrong refresh rate. This can also happen if AERO is disabled in Vista and Windows 7, or DirectX exclusive mode is Off in Windows XP, or VMR9 is used in Windows Vista and Windows 7.




    Corrupted Video frame / Pixellation




    It’s an API built on top of Direct3D that gives application an easy way to draw video to screen. It is used mainly in Windows XP. It also exists in Windows Vista and Windows 7, but it is not recommended in Windows Vista and Windows 7 and it is not supported by the team in those Operating systems.


    The enhanced video renderer (EVR) is a component that displays video on the user's monitor. It is used by Windows Vista and Windows 7. It can be installed into Windows XP by installing .NET framework 3.5, but it is not recommended to use it in Windows XP and it is not supported by the team in Windows XP. Using EVR in Windows XP is software mode only, so DXVA hardware acceleration is not possible.

    Refresh rate

    Refresh rate is: how often image is drawn to screen by Display itself. Common refresh rates are 50 Hz and 60 Hz that are used with TV set or Monitor. Also 100 and 75 Hz are used. It is quite common that FPS and refresh rate do not match and it produces some visible errors to picture. In Europe PAL is used, so Ine should set refresh rate to 50Hz. In America 60Hz is in use. And then there is movie files,dvd's and blu-ray's which could have almost any FPS as could be imagined. That is why MediaPortal supports Dynamic Refresh Rate, More of that later in this document.


    Frames per second indicate how many images per second are in source material, like in video DVD or in LiveTv.


    Standard Definition video. 480p, 480i, 576i and 576p


    High Definition video. 1080p/50,  1080p/60, 720p/50 and 720p/60

    DXVA, DXVA 2

    Is a specification that allows video decoding to be hardware (GPU) accelerated.

    Display Adapters

    There are mainly two manufacturers that produce display adapters suitable for HTPC use. NVIDIA and ATI, Intel is also trying to push itself into market with i5 and i7 platforms.

    All modern graphics adapters are capable of playing SD content.  HD content on the other hand requires powerful CPU if HD content is to be played without graphics adapters help. This can be done by using for example CoreAVC codec. Most enjoyable and recommended is to use good Graphics adapter and DXVA capable codec. MediaPortal requires more powerful graphics adapter than for example PowerDVD recommends. This because MediaPortal GUI is much more advanced than in PowerDVD and it requires some slice from the GPU power to GUI handling.


    Some soft and hardware manufacturers suggest that NVIDIA card with VP1 PureVideo support is good for HD content. This not entirely true becuase of the GUI handling in Mp, and second thing is that marketing man wants to sell cheap product with HD capability, So it needs to be at least VP2, but recommended is VP3 or VP4 PureVideo capable Graphics adapter. You can check NVIDIA adapters and their HD capability from Wikipedia.


    With ATI’s terminology Hardware assisted decoding is UVD. UVD 2 revision at least is recommended. Check your adapter’s capability from Wikipedia:


    With INTEL one should have at least G45 chipset. i5 and i7 platforms are also very good.

    In INTEL platform there is one flaw that should be mentioned. In 23.976 fps material there is lot of stuttering reported. Refer to this forum for more information:

    Display Refresh Rate what and why ?

    At first we need to define the difference between Monitor and TV's refresh rate and frame rate of source material. There these standards that are used in TV and movie industry:

    • 50i is interlaced 50 frames per second film, but it has only half of original vertical resolution. Resolution is then restored in de-interlace process.
    • 60i is 59.94 (60000/1001) to be precise, but it has only half of original vertical resolution. Resolution is then restored in de-interlace process.
    • 30p is progressive i.e. non-interlaced frame rate. It was introduced to bring clarity into high speed images like in sports.
    • 23.976p (24000/1001) is frame rate used in Blu-ray systems.           
    • 29.97p (30000/1001) is NTSC film definition.
    • 24p is also non-interlaced format. It is slowed down to 23.976 for NTSC and speed up for PAL/SECAMsystems.
    • 25p is non-interlaced format derived from PAL 50i standard to gain some “Cine"-look and feel. 50i has better motion response in fast moving objects.
    • 50pand 60p are HDTV formats. Even they are not part of DVB or ATSC standards, they are commonly used by broadcasters. These can be also be marked as 1080p/50 , 1080p/60, 720p/50 and 720p/60 Also Blu-ray and HD-DVD uses these formats.
    • So frame rate is actually frames per second, which is actually same as Hz (Hertz = 1/s). Frame rate and Refresh rate are two sides of same thing. When Frame rate represents the speed of how many images are filmed per second into source material(DVD, Video file, Live TV) and refresh rate defines how many images TV-set or monitor displays in second. Best quality is achieved when we can set these rates to match each other. It is not always possible to achieve this, because not all displays support all frame rates that source material can have.

    Dynamic Refresh Rate changer

    One way to ease MediaPortal’s job is to use refresh rate changer built-in into MediaPortal. That way your monitor/TV set and Display adapters refresh rate is changed to match source materials frame rate. This can be done in MediaPortal configuration:




    As of MediaPortal v1.3. Final, the default settings for refresh rate changer are optimized for Blu-ray, NTSC & ATSC.

    The table looks like this, if display can handle all these refresh rates:



    Frame rate(s)

    refresh rate


























    If display cannot handle all these refresh rates, table should be modified so that refresh rate is as close as possible to the frame rate For example Philips 5532D supports only 24p,50p and 60p refresh rates, so table should look like this:



    Frame rate(s)

    refresh rate


























    This of course applies only if your monitor or TV set is capable of using that refresh rate. Also Display adapters have some restrictions on refresh rates. At this point it is necessary to check both Display’s and graphic adapter’s manuals for options you have to use Dynamic refresh rate control. And moreover In PAL countries most safe setting is to set refresh rate for 50Hz and in NTSC countries to 60 Hz.


    You can check by yourself how MediaPortal behaves with your video material and your screens refresh rate by pressing shift+1 i.e. “!” character. Here is example image where display refresh rate does not match fps of the video. See how graphs are jumping up and down. These should be as straight as possible, but it is not always possible to achieve that. So MediaPortal is “retiming” single video frames so that video is played smoothly.



    Cleaning Drivers

    Vista and Windows 7

    Now it’s time to a bit advance things to ensure that your display adapter’s driver is really using the dll’s that was in driver package. A bit of background first. In Windows Vista and 7 there is a hidden place called Driver cache or Driver repository where Windows stores all drivers that you have ever installed into windows. It could be good thing sometimes, but in most cases when user installs and de-installs drivers to find best for video playback it just messes things up. When you install driver, then installer is not always able to determine which dll to update and that leads to unstable system. Especially this cleanup is needed when downgrading driver pack. 99% of the driver installers are not meant for downgrading and they don’t handle dll version comparing backwards. If up/downgrading has been done few times, it is almost sure that there is dll’s of wrong version.

    We need to clean up that repository before installing display driver, by using little utility in Windows Vista and 7. It is called pnputil. Open up command prompt with administrator privileges and execute “pnputil -e”. This should list all drivers ever installed into system.



    As you can see drivers are named as oemX.inf, but you can use “Driver package provider :”  and “Class:” lines to determine which is display driver.

    I suggest that you have only one driver installed for display adapter. Here is how:


    1. First Uninstall current driver:



    2.  Then delete all instances of Display drivers with “pnputil –d –f oemX.inf” or “pnputil –d oemX.inf”, where X is driver identifier. “-f” in command states that driver deletion is forced. When you reach the point when no display drivers are listed with pnputil –e, next step is to reboot to check what driver windows loads. If it’s standard VGA driver, then we are in good road. If not then there is still something in Driver repository and they need to be deleted. This should be repeated as long as Windows loads standard VGA driver at start-up.

    At this point 3D guru’s driver sweeper should be used to clean leftovers from installation dirs.

    It can be downloaded here:

    When this is done, it is time to install correct driver for display adapter.


    In XP it should enough to uninstall driver and then use 3D guru’s driver sweeper.

    Choosing display driver

    I’m not going to give you any driver versions for your system, but instead I encourage you to do the cleaning part, as instructed above, while testing, and if you don’t find good driver, give a try to manufacturer’s version of the driver for your Os, I mean the driver that came with card in installation disk. Reason for this is that manufacturers often tweak reference drivers for their own purposes and maybe there is something in Hardware that they have fixed with own version of the driver.


    Other way to start finding good driver is to try the latest and then go back version by version until good one is found. When good driver is found it is not encouraged to update driver just because there is one.


    NVIDIA graphic adapters seem to be very sensitive for hardware/driver combination, so absolutely correct answer is impossible to give, so test and try.


    It seems that Ati is not so sensitive for driver versions, although there are some restrictions in Ati drivers like reference frame count. Currently ATI has also problems with Vista and Windows 7 also. Video may appear heavily corrupted. Hope they fix these soon.

    VMR9 vs. EVR

    In Vista and in Windows 7 AERO has to be enabled and EVR used as renderer. In XP Renderer should be VMR9. If you suffer from Tearing, you should enable V-Sync in 3d settings in Graphic Card driver’s control panel. This because the way Windows XP, Vista and 7 are designed by Microsoft. EVR can also be installed into XP with .NET framework 3.5, but it won’t use DXVA at all.

    EVR is more resource hungry rendering system than VMR9, but it is only supported rendered in Windows Vista and 7.

    External helper software

    HTPC has one disadvantage over STB and standalone DVD/Blu-ray players. It is the fact that Audio and Video hardware uses different crystals to generate reference clock which are used to timing of audio and video samples. Even Graphic cards that are able to produce audio output use different crystals for audio and video. These crystals are not in sync and they have tended to drift apart. This can cause problem to playback experience. Playback software tries to keep lip-sync, and if Video and audio speeds are slightly different (because of the differences in crystal) it must be compensated somehow. That is why many users use Reclock as audio renderer. With current MediaPortal versions Reclock should be used with Vsync disabled in ReClock setup, as it interferences with MediaPortal Vsync handling. Instead let ReClock to do audio re-sampling and slight speed adjustment so that audio follows video nicely. ReClock is not recommended for LiveTv although some users have good experiences with LiveTv also.

    There are currently sub-projects ongoing to provide similar functionality into MediaPortal so that ReClock is no longer needed. You can check them from these threads: and

    Some of the users have reported that EVR presenter of above thread has helped a lot for playback quality. New EVR presenter will in Mp from 1.1.2 onwards.

    Anyway recommended configuration for ReClock:








    Although slowdown and speedup default % might not be enough. I increased it into 10%, but that is quite extreme. On another hand TV companies do it all the time when they have to fit certain movie into timeframe in schedule.

    You must also set Reclock as audio renderer for video types that you want to use it:





    AERO is component / GUI rendering technology of Windows Vista and 7. The way it is implemented into display architecture that EVR won’t work very well without it.  That is because V-sync managed by AERO and MediaPortal snaps timing from there.  If MP installation reports that AERO is disabled, or if you  suspect problems with AERO, this article may help you.


    This is how Microsoft explains it:

    DirectX Video Acceleration (DXVA) is an API and a corresponding DDI for using hardware acceleration to speed up video processing. Software codecs and software video processors can use DXVA to offload certain CPU-intensive operations to the GPU. For example, a software decoder can offload the inverse discrete cosine transform (iDCT) to the GPU.

    In DXVA, some decoding operations are implemented by the graphics hardware driver and are executed in the GPU. This set of functionality is termed the accelerator. Other decoding operations are implemented in software and executed in the CPU. The set of functionality implemented in software is termed the host decoder. Processing performed by the accelerator is called off-host processing. Whenever the accelerator performs a decoding operation, the host decoder must convey to the accelerator buffers containing the information needed to perform the operation.

    The DXVA 2 API requires Windows Vista or later. The DXVA API is still supported in Windows Vista for backward compatibility. An emulation layer is provided that converts between either version of the API and the opposite version of the DDI:


    ·         If the graphics driver conforms to the Windows Display Driver Model (WDDM), DXVA API calls are converted to DXVA 2 DDI calls.

    ·         If the graphics drivers use the older Windows XP Display Driver Model (XPDM), DXVA 2 API calls are converted to DXVA DDI calls.


    API Version


    Video Renderer Support


    Windows 2000 or later

    Overlay Mixer, VMR7, VMR9 (DirectShow only)

    DXVA 2

    Windows Vista and Windows 7

    EVR (DirectShow and Media Foundation)


    In our point of view smooth HD playback almost always requires DXVA to be used. Although with some codecs it is possible to have good HD playback if CPU is powerful enough. More about DXVA in codecs section.

    Update Motherboard Bios

    Motherboards with integrated graphic adapter might need bios update to solve playback problems. One should remember when dealing with bios versions or driver versions that latest is not always the best choice.

    Check other source of interference

    DVB-T is less resistant to interference than DVB-S or DVB-C. There have been reports that Wlan can disturb DVB-T signal badly. So if it is possible, I Suggest you move it as far as possible from dvb tuner.

    DPC Latency

    Bad drivers can cause DPC latency. It can be checked with DPC Latency checker that can be obtained here: It is easy to use. Just run it and it will tell the result.



    Windows 8 Compatibility: The DPC latency utility runs on Windows 8 but does not show correct values. The output suggests that the Windows 8 kernel performs badly and introduces a constant latency of one millisecond which is not the case in practice. DPCs in the Windows 8 kernel behave identical to Windows 7. The utility produces incorrect results because the implementation of kernel timers has changed in Windows 8 which causes a side effect with the measuring algorithm used by the utility. Thesycon is working on a new version of the DPC latency utility and will make it available on this site as soon as it is finished.

    Alternatively you could use LatencyMon.

    DMA mode

    On some cases DVD drive or HDD has been in “non – DMA” mode. This might happen if IDE cable is not good enough, or Bios setting is wrong, or it is set wrongly in windows device manager.




    Bad signal

    One source of bad quality TV picture is signal. It is quite easy to check it by yourself, for example by testing time shifting in TV Server Configuration->Manual Control.




    Like always there is always but, and so is this time. Not all tuner cards and drivers provide signal quality information in correct manner, so that it could be displayed. If you have doubts and possibility to check it with dedicated hardware like TV set or STB, please do so, so that one source of bad experience can be ruled out.


    This is probably hardest part to give any specific answers. On most cases XP drivers are in good shape. It takes longer to get good drivers for new Os versions like Windows 7 now.  And some manufacturers do it better that others. It’s a matter of testing which driver works for you.

    Network Provider

    There are Windows versions that come with Media Centre and in those versions there is a “generic network provider” for all types of tuner cards. In regular windows versions there are network provider specific for each tuner types, like dvb-t, dvb-s etc. In most cases the default network provider is good, and in fact you can change it only in windows containing MCE, but in some rare cases, like old pinnacle 70e dvb-t tuner the “generic network provider” did not work at all in Vista and Windows 7, but worked good with dvb-t network provider. So it is worth of try if anything else won’t work.


    Time shifting buffer

    On some cases bad experience can be due to HDD performing poorly. There are few things that can be tried. Using RAM Disk is one, if user has enough RAM. It can be obtained for example here:

    User should also check that DMA mode is used for HDD that is used for time shifting. Refer to chapter 2.10. Every Windows versions use page file and TEMP folders to store temporary data and/or extend free RAM. If user has more than one HDD these should be redirected to different HDD that is used for time shifting.

    Page file

    Page file can be set in computer properties:




    Temp folders

    Temp folders can be redirected here:




    Codecs are probably most important thing with Graphic card itself that affect video quality. Many users prefer codec packs because they are easy to use. put it this way. There are good and bad packages. I prefer to install only codecs I need for file types i’m using. This is not going to be a fully covered instruction what codes to use, but observations that have worked well.  See our Codecs Guide for the full instructions.

    Whatever codecs you are planning to use, it is good practice to check codecs with filmerit, so that errors can be avoided:

    Suggestion of codecs is just a list that has worked for me, so it is not to be taken too seriously. Instead Best codec depends on OS, HW & driver combination. So it is just matter of trying.

    On Windows XP:

    • Mpeg-2 Video Decoder: MPC – MPEG-2, Cyberlink 7 – 10, NVIDIA video decoder
    • H.264 Video decoder: Cyberlink H.264/AVC Decoder (PDVD8) & 9, CoreAVC (With NVIDIA Cuda capable card, or powerful CPU)
    • MPEG / AC3 audio Decoder: MPC – MPA Decoder filter, AC3 filter, FFDshow

    On Windows Vista:

    • Mpeg-2 Video Decoder: MPC – MPEG-2, Cyberlink 7 – 10, NVIDIA video decoder
    • H.264 Video decoder: Cyberlink H.264/AVC Decoder (PDVD8) & 9, CoreAVC (With NVIDIA Cuda capable card, or powerful CPU)
    • MPEG / AC3 audio Decoder: MPC – MPA Decoder filter, AC3 filter, FFDshow

    On Windows 7:

    • Mpeg-2 Video Decoder: Microsoft DTV-DVD Video decoder, Cyberlink 7 - 10
    • H.264 Video decoder: Microsoft DTV-DVD Video decoder, Cyberlink 7 - 10
    • MPEG / AC3 audio Decoder: Microsoft DTV-DVD Audio decoder, MPEG / AC3 audio Decoder: MPC – MPA Decoder filter, AC3 filter, FFDshow

    Something else might be necessary to install for different source material, like DivX, Mkv and Flv. There are more of source filters than decoders to containers. I prefer to install them only if needed.

    DXVA is it needed?

    On SD material not necessary, But for excellent HD quality it is Must.

    DXVA capable codecs

    Cyberlink codecs have proven to be quite good and stable in most cases. In Windows 7 Microsoft’s own codecs support DXVA and DXVA 2. FFDshow and MPC-HC has DXVA capable codes too. Archsoft and WinDVD provide also DXVA capable codecs.

    Checking that DXVA really is used

    First of all you should check that your video card, driver, OS combination is capable of using DXVA. You can check it by running DXVA checker. It can be obtained from

    Author’s site:




    ATI owners are probably happy with ability to tweak AVIVO on for all material:

    Right Click of the rows in window.





    With load button there is also Avivoall file provided with DXVAChecker that is tailored for ATI cards. 

    Next you can run MediaPortal in windowed mode and start some HD video and pause it by pressing spacebar. Start Monogram GraphStudioNext. In Vista and Windows 7 it must be started with “run as administrator”. GraphStudioNext can be downloaded here:

    In Windows Vista and Windows 7, you also need to do install proppage.dll

    and from there look for post #9 to obtain






    Right click Video decoders output pin (which ever it is: Microsoft, Cyberlink etc...) and choose properties:



    Look for the field biCompression. Some codecs tell here right away that DXVA is in use. Some others tell for example NV12. In that case you should check DXVAChekers screen if that format is supported for DXVA:




    In these example images it is, and I’m sure DXVA is in use, but my mobility Radeon x1300 is so underpowered that CPU usage is still around 50%.

    But probably easiest way is to keep MediaPortal windowed and play HD material. Then open task manager and look CPU usage. It should be less than 30% for MediaPortal with good graphic adapter.

    DVD playback

    If you have problems with DVD title menus, you should disable DXVA in DVD codecs section in MediaPortal configuration:


    System cleaning and keeping in shape

    Keeping system running smooth you should defrag your HDD regularly. Most important this is when your system, recordings and time shifting folders are in same partition. Recordings seem to be naturally heavily fragmented.

    Don’t bloat your start-up. It is wise to try to keep automatically started software in minimum, as well as whole system. So minimum number of background tasks is always the best solution.

    Try to keep epg grapping in such time of the day that you are not using the system, as it might generate huge amount of activity in Sql server.

    Check other software that might disturb playback experience. Like antivirus.

    Once you have good running system it would be good to make a backup with method that is suitable for you OS. For example Restore point, Ghost image backup etc. Whichever is easiest for you to get system back on its feet in case it is messed up.

    System requirements

    General note: At least 256 Mb of display memory recommended to in any graphic adapter listed below.

    DVD, SDTV and Video


    • Intel
      • Minimum - Pentium 4 2.4 GHz
      • Recommended - Pentium 4 3.0 GHz or above
    • AMD
      • Minimum - Sempron 2600+ 1.6GHz
      • Recommended - Athlon 64 2800+ 1.8GHz or above


    • AGP or PCI Express graphic accelerator supporting DirectX 9.0 or above.

    1080p based Blu-ray, HD-DVD, HDTV and HD Video


    • Intel
      • Minimum 
        Intel® Core™ 2 Duo CPU E4400 2.00GHz or
        Intel® Core™ Duo T2600 2.16G
      • Recommended 
        Intel® Core™ 2 Duo E6400 2.13GHz or
        Intel® Core™ 2 Duo T7400 2.16GHz
    • AMD
      • Minimum - AMD Athlon™ 64 X2 4600+ 2.4GHz
      • Recommended - AMD Athlon™ 64 X2 5600+ 2.8GHZ


    • NVIDIA
      • Recommended - GeForce 8600 GT or higher
    • AMD
      • Recommended - ATI Radeon HD 3800 Series or higher
    • Intel
      • Recommended - Intel G45 with help of powerful CPU , i5 is at least on safe side. Also note that Intel GPU’s has some stuttering problems in certain material. Refer to Chapter 2.

    1080i based Blu-ray, HD-DVD, HDTV and HD Video


    • Intel
      • Minimum 
        Intel® Core™ 2 Duo CPU E4400 2.00GHz or
        Intel® Core™ Duo T2600 2.16G
      • Recommended 
        Intel® Core™ 2 Duo E6400 2.13GHz or
        Intel® Core™ 2 Duo T7400 2.16GHz
    • AMD
      • Minimum - AMD Athlon™ 64 X2 4600+ 2.4GHz
      • Recommended - AMD Athlon™ 64 X2 5600+ 2.8GHZ


    • NVIDIA
      • Recommended - GeForce 8800 GT or higher
      • Recommended - GeForce 9600 GT or higher
      • Recommended - GeForce GT 220 or higher
    • AMD
      • Recommended – From HD 3xxx series HD 3800 or higher
      • Recommended – From HD 4xxx series HD 4550 or higher
      • Recommended – From HD 5xxx series HD 5670 or higher
    • Intel
      • Recommended - Intel G45 with help of powerful CPU, i5 is at least on safe side. Also note that Intel GPU’s has some stuttering problems in certain material. Refer to Chapter 2.

    Running the latest version?

    V1.15.0 - released June 2016
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