Improved video playback quality (1 Viewer)

splatterpop

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  • December 17, 2007
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    This is certainly for the enthuisiasts only (like myself), but the results are striking.

    I was looking up info about the so-called "100Hz" technology implemented in most TV sets and the algorithms which provide it. At some point, I came across some scripts for AVIsynth which provide such functionality.

    I went on to some experimenting and managed to come up with a setup, not yet perfect, but easy to implement, and I decided to share my results.

    The AVIsynth script will take any video source with frame rates below 31fps and upscale it to 50Hz (or whatever refresh rate), using motion vector estimation and image interpolation. I limited the processable image size due to limited CPU resources (passive cooling). So far, the setup looks quite stable.

    The solution is based on AVIsynth 2.6 and mvtools 2.5.11.3. ffdshow is used as decoder for SD material. All codecs are set to libavcodec.

    I find the results remarkable, imo SD video image quality improvement is way beyond what is achievable with sharpening/denoising only.

    Current problems / downsides:
    • does not appear to work with DXVA or QuickSync - hardware decoding must be disabled
    • start of video stream / tv program change / seek produces flicker
    • does not use all of the cores of the CPU
    If there are any AVIsynth buffs around, let me know how to improve the script.

    Cheers,
    splatterpop
     

    Attachments

    • refps_dvd_codecs.png
      refps_dvd_codecs.png
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    • refps_tv_codecs.png
      refps_tv_codecs.png
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    • refps_video_codecs.png
      refps_video_codecs.png
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    • refps.avs.txt
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    • ffdshow.reg.txt
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    Last edited:

    splatterpop

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    I think it aplies to all sorts of material, however I was only able to test it on my own system. The limitations are built into the script (fps < 31, image height < 601) as well as the target frame rate of 50Hz, which should be set according to the monitor.
     

    splatterpop

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  • December 17, 2007
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    Ok I want to share my latest learnings here.
    1. SVP Project
    http://www.svp-team.com/ provides a refactored version of mvtools, along with a control program. While some problems, like artefacts, persist, others are solved, such as distorted image during seek, adapting to HD material and the necessity of avs coding.
    2. HDMI limitations
    As far as I was able to find out, HDMI specifications do not allow refresh rates beyond 50Hz at 1080p resolution. There are reports about attempts at tweaking the EDID or overclocking the graphics adapter, but it seems there are as many reports of failures. My conclusion is that for the classic living room combination of HTPC, HDMI cable and HD monitor, 50Hz is the limit.
    3. Higher refresh rates
    Refresh rates such as 100Hz and beyond are possible only if frame interpolation is shifted away from the HTPC into the monitor hardware. It would be interesting to learn which monitors have such capabilities accessible through HDMI (not just the internal tuner, like mine does)
    Cheers,
    splatterpop
     

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