Gettinging smoother playback of video/tv/dvd

Discussion in 'Tips and Tricks' started by Frodo, July 24, 2005.

  1. Frodo
    • Team MediaPortal

    Frodo Retired Team Member

    Joined:
    April 22, 2004
    Messages:
    1,518
    Likes Received:
    121
    Occupation:
    Professional .NET developer
    Location:
    The Netherlands
    Ratings:
    +121 / 0
    Home Country:
    Netherlands Netherlands
    Setting your windows desktop to a higher refreshrate
    makes watching tv/video/dvd smoother.



    You can check this by playing some media and pressing !
    note the jitter value

    This was 21 when i used 50Hertz as refreshrate
    This is now 3 with windows desktop set to 100Hertz

    Offcourse if your monitor does not support 100Hertz,
    then you can just choose the highest frequency supported
    (for example 70,75,80Hertz)

    Frodo
     
  2. Google AdSense Guest Advertisement



    to hide all adverts.
  3. SurFan

    SurFan Portal Member

    Joined:
    August 7, 2005
    Messages:
    9
    Likes Received:
    0
    Ratings:
    +0 / 0
    hi,

    sorry frodo, but you get only best results, if you choose an EXACT multiple of the framerate of the playing video. If you play a PAL DVD (25fps) you have to chose 50, 75, 100. The VERY best results you get, if you use Powerstrip (www.entechtaiwan.com) to set the refresh rate correctly to 1/1000 hz.

    But as the video renderer always syncs itself to the audio renderer, you can even get judder in this case. Here comes ReClock in (reclock.free.fr). Reclock replaces the audio renderer and syncs the audio to the video. This works even with SP/DIF passthrough, as Reclock duplicates or drops audio frames if necessary. This is not a problem, if you have set powerstrip up correctly.

    I have a front projector as display type where every single dropped/repeated frame is horrible. Whith the combination of powerstrip and reclock, I have in 90-95% not a single dropped/duplicated frame throughout a whole DVD

    Ralph
     
  4. rtv
    • Team MediaPortal

    rtv Retired Team Member

    Joined:
    April 7, 2005
    Messages:
    3,622
    Likes Received:
    301
    Occupation:
    CTO at ES2000
    Location:
    Osnabruck
    Ratings:
    +301 / 0
    Home Country:
    Germany Germany
    Show System Specs
    I disagree - you can get small glitches which most people are more sensitive to than video juttering..
     
  5. shawnwc

    shawnwc Portal Member

    Joined:
    August 11, 2006
    Messages:
    30
    Likes Received:
    0
    Occupation:
    Telecom Engineer
    Location:
    Boston, MA
    Ratings:
    +0 / 0
    What about HD?

    This may be a stupid question, since HD isn't exactly the same... But here goes...

    I'm pushing 720p out my DVI port on my video card... Refresh rates isn't an option then - correct?
     
  6. knutinh

    knutinh Portal Pro

    Joined:
    September 4, 2005
    Messages:
    558
    Likes Received:
    2
    Ratings:
    +2 / 0
    I have read lots of info on this around the net. Getting a complete understanding is difficult.

    Cinema movies are shot at 24 frames/second. This is enough to capture the motion itself, but cinema projectors use shutters to project those frames 48 or 72 times a second. This reduce flickering, and relie on a mechanism called "image retention" in our vision.

    Now, tv-systems are 50Hz in countries that use 50Hz power supply, and 60Hz in those countries that use 60Hz power supply. The reason is both that CRT tv elechtronics could use the power supply as a stable clock, but also that movies taken with 50Hz light bulbs using a 60 Hz camera will flicker!

    So, how do you present 24fps movies on a telly? For PAL (50Hz) countries, this is usually done by speeding up the film by 25:24 so that it is actually about 4% shorter. The same is of course done to audio to keep sync. Then each interlaced half-frame will contain odd or even lines of its corresponding source frame. In NTSC-land (60Hz), a special "cadence" called 3:2 is used where a source frame will either result in 3 or 2 interlaced half-frames. This introduce a slight stutter or uneven progression. It is possible to reverse this process so that 24p->60i-24p conversion can be done with no loss (in theory). In practice, many SD broadcasters will filter interlaced transmissions to avoid "jumping" meaning that some information is lost.

    Most flatscreens (almost all HD-ready screens are plasma or lcd here in europe) can only do 60Hz. Some, notably Pioneer plasmas will accept 24p input and do a 3:3 pulldown, just like the movie theaters.

    AFAIK, VGA cannot do 50Hz. As many flatscreens tell you to use VGA for PC, this renders them less usefull for playback of PAL material from PC.

    For me, this has major implications as I want to replace my surround receiver with pure software audio decoding so that I can use Reclock with full fidelity.

    Upcoming HD-DVD and Bluray formats store the HD video content as 24p and then the playe hardware will render this as (typically) 1080@60i at its outputs. I am curious as to how this will be implemented on PCs.

    regards
    KNUT
     
  7. flyblackbox

    flyblackbox Portal Member

    Joined:
    August 30, 2006
    Messages:
    6
    Likes Received:
    0
    Ratings:
    +0 / 0
  8. NLS

    NLS Portal Pro

    Joined:
    April 26, 2006
    Messages:
    922
    Likes Received:
    0
    Occupation:
    IT
    Ratings:
    +0 / 0
    Home Country:
    Greece Greece
    I have my 1920x1080 progressive LCD set to 50Hz (can also do 60), exactly because of PAL TV
     
  9. knutinh

    knutinh Portal Pro

    Joined:
    September 4, 2005
    Messages:
    558
    Likes Received:
    2
    Ratings:
    +2 / 0
    My 40" LCD will do 1366x768 at 1:1 pixel only at 66Hz - at least that is what I have accomplished tweaking powerstrip.

    It will do 720p@50Hz and that looks a lot better for PAL material even though it is passed through a 2nd pass of scaling.

    The frustrating thing is that most manufacturers and customers dont care. They dont know what 1:1 pixel is, dont know the importance of correct framerate etc. As long as the "HD-ready" logo is there, they will gladly accept poor black levels, jumping camera pans and bad internal scaling/deinterlacing :-(

    regards
    Knut
     
  10. NLS

    NLS Portal Pro

    Joined:
    April 26, 2006
    Messages:
    922
    Likes Received:
    0
    Occupation:
    IT
    Ratings:
    +0 / 0
    Home Country:
    Greece Greece
    indeed

    man it's tough... 66Hz is bad for PAL/NTSC/HD/you name it

    anyway this is how I got my nice AMOI 37" 1920x1080P LCD... I first talked to China and made sure they made a new firmware that actually locks 1:1 on 1920x1080 through the HDMI (at 30/50/60Hz)... they did and then I got it. :) (sound Utopia, well this is what happened)
     
  11. KRA

    KRA Portal Pro

    Joined:
    July 5, 2005
    Messages:
    145
    Likes Received:
    5
    Ratings:
    +5 / 0
    Home Country:
    Norway Norway
    framerate

    I thought the PAL/NTSC/movies/1080i framerate issue wasn't such a big problem when using the WMR9 render? I do get terrible tearing in MP though on my 60hz LCD TV, but this is a problem with all framerates so I believe it's an unrelated issue. Because DX Exclusive mode completely removes the tearing if vsync is on.

    I wish MP would be able to use vsync without using DX Exclusive mode.
     
Loading...

Users Viewing Thread (Users: 0, Guests: 0)

  1. This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
    By continuing to use this site, you are consenting to our use of cookies.
    Dismiss Notice
  • About The Project

    The vision of the MediaPortal project is to create a free open source media centre application, which supports all advanced media centre functions, and is accessible to all Windows users.

    In reaching this goal we are working every day to make sure our software is one of the best.

             

  • Support MediaPortal!

    The team works very hard to make sure the community is running the best HTPC-software. We give away MediaPortal for free but hosting and software is not for us.

    Care to support our work with a few bucks? We'd really appreciate it!