25 and 30 fps to 24 conversion

Discussion in 'ReClock' started by pacemaker1000, Jan 8, 2011.

  1. pacemaker1000

    pacemaker1000 Well-Known Member

    I am in Pal land and have used the invaluable Reclock since its beginning to give smooth playback
    I set my video card to 720px50Hz and Reclock to 25fps locked. All blurays and 30hz stuff looks great through mpc and TMT

    I am upgrading to a 1080p24 display and want to set my video card to 1080px24hz so my question is will Reclock work in reverse. That is output 25 and 30 fps material to 24 correctly or should I leave things as they are?
  2. James

    James SlySoft Development Team Staff Member

    You should playback PAL material at 24 fps anyway, so you can hear the sound the way it should be heard:


    30 fps stuff won't work at 24 Hz.
    Last edited: Jan 8, 2011
  3. pacemaker1000

    pacemaker1000 Well-Known Member

    unless i lock the output to 25fps i get stutter as my display will not do 24/48hz only 50/60hz
    if it did then surely i would not need Reclock?
    i thought that in order to get smooth video i had to put up with the +4% speed up
    i just tried 'auto' with pal slow down and the clock stays amber plus i get micro stutter

  4. James

    James SlySoft Development Team Staff Member

    Didn't you say "I am upgrading to a 1080p24 display" ? :confused:
  5. pacemaker1000

    pacemaker1000 Well-Known Member

    yep, but still stuck with the old one for a while and thought i was missing out on something :)
  6. Jong

    Jong Well-Known Member

    I know you did not mean this James, but for the casual reader(!), real PAL material should not be played back @24fps. Only PAL versions of 24fps movies should be slowed down i.e PAL DVDs and PAL recordings of (most) movies and US drama.

    If you have a 25p/24p display and are interested in real PAL material as well as movies/US shows there is really no completely automatic way of choosing the right speed. You either need to do it manually each time, or sort/name your videos in a way that allows you to automatically set refresh rate.

    You should not need to "lock" Reclock, though, to get correct playback @25Hz. All you should need to do is set your refresh rate to 50Hz, set Reclock to "auto" (unlocked) and max speedup to 5% (max slowdown to 5% for PAL sped-up movies @24fps). This will make working at variable refresh rates much easier. Then all you need to do is:

    - set refresh rate to 24Hz for Blu-ray, NTSC movies/Drama, PAL Sped-up movies

    - Set refresh to 50hz for "real" PAL material

    - Set refresh rate to 60Hz for NTSC video (30fps/interlaced) material.

    Reclock will then do what is needed without any change to its config.
    Last edited: Jan 11, 2011
  7. pacemaker1000

    pacemaker1000 Well-Known Member

    many thanks
    when i get my 24 capable projector i will of course set it to 24hz
    at the moment though i am stuck with 50Hz. i tried 'auto' but then the clock does not go greeen?
  8. Jong

    Jong Well-Known Member

    Make sure your max speedup is set to 5% and "guess better speed when hardware refresh rate does not match" is ticked. Then auto should work fine.
  9. pacemaker1000

    pacemaker1000 Well-Known Member


    i have no idea what changing the default 1% to 5% in the max speedup value does but in auto now everything goes green
    placing i tick in pal speed down does nothing anymore but everything now sounds right

    this would seem a better option than setting by htpc output to 24hz even when i have the display to handle it as at least now my pal stuff/tv works ok

    Last edited: Jan 13, 2011
  10. Jong

    Jong Well-Known Member

    What it says really. It allows Reclock to speed up the video up to 5% in order to get smooth playback. 24fps + 4.2% = 25fps, so you need slightly less than 5% speedup (but much more than 1%) to play 24p material smoothly @50hz.

    Glad it worked!
    Last edited: Jan 14, 2011
  11. pacemaker1000

    pacemaker1000 Well-Known Member

    i cant believe this is not made clearer or default for PAL users!
  12. James

    James SlySoft Development Team Staff Member

    Because it is a "Bad Thing(tm)" to do. :D Speeding up 24fps to 25fps (PAL) will result in "chipmunk voices".

  13. Jong

    Jong Well-Known Member

    Not a bad thing if you have a PAL (50Hz) display!
  14. James

    James SlySoft Development Team Staff Member

    True, but a very bad thing if you don't. ReClock really doesn't know (it could, but at the moment it doesn't).

    I personally would even prefer a 60Hz display (all should do that) and let ReClock run at 24fps. Just a matter of personal taste. Chipmunk? Or 2:3 pull-down stutter? I'll take the micro stutter.
    Last edited: Jan 14, 2011
  15. Jong

    Jong Well-Known Member

    I think this is a common thing.

    Most who live in PAL land, are used to PAL speedup on DVD and, still, on TV, find 3:2 pulldown judder horrible and prefer altered pitch.

    Those who live in the NTSC world barely notice 3:2 pulldown and prefer correct pitch.

    But, I may be missing something, but I really cannot see what is wrong with setting a 5% default for max speedup. With normal refresh rates and media speeds it only kicks in if someone IS using 50Hz AND plays 24p material. In this case speedup must be better than playing @24fps. The only time someone would want to change this is if they are using Reclock scripts to change the refresh rate; Then they want the yellow event to generate the switch. But if they are savvy enough to use scripts (small minority) they can surely change the speedup figure themselves, no?
  16. James

    James SlySoft Development Team Staff Member

    ReClock would stay "green" so it wouldn't change your refresh rate to 24Hz.
  17. Jong

    Jong Well-Known Member

    i realise that. But that only matters if you are using scripts. And you need to manually edit the script yourself to use it, so its reasonable to expect someone doing that to also know how to change the speedup to 1%, isnt it?

    Better that the default gives smoothest playback for the novice, which would mean using PAL speedup when playing 24p @50Hz?