NTSC <-> PAL framerate conversions

[Frodo]

hi all,

we probably all know that ntsc encoded movies are choppy when viewed on a pal box and vice versa
problem is that ntsc movies are encoded in framerates like 23.97fps or 29.978 fps while pal is 25.0 fps
this means that frames must be skipped/duplicated which results in choppy/jerky playback

however, what if we play a movie faster/slower to match the 25.0fps

take for example a 23.97fps movie. if we play this 25/23.97 times faster then normal, so at 1.0429x then its excactly 25.0 fps and should play perfectly smooth.
same for 29.97fps if we play that 25/29.97 at 0.83394x its 25.0 fps

sure the movie plays back a bit faster or slower, but would anybody notice this? i dont think so

anyway let me know your thoughts about this
if more ppl think this is a nice idea i can implement it in xbmc
frodo


frodo

[kraqh3d]

could this be made optional so we can play around with both modes to compare them?

[Nickman]

Originally Posted by (frodo @ dec. 29 2003,15:28)

however, what if we play a movie faster/slower to match the 25.0fps

take for example a 23.97fps movie. if we play this 25/23.97 times faster then normal, so at 1.0429x then its excactly 25.0 fps and should play perfectly smooth.

hehe. should work. the japanese have this system in some dvd players. but not to get around the ntsc/pal issue. just to save time. :d

so how can millions o japanese be wrong go for it!

[zilvershadow]

what about the audio stream?
isn't that going to get out of sync?

[Frodo]

i added the option to xbmc
you can disable/enable it under settings->screen with the
'adj. framerate' button

(remember you gotta restart the movie b4 when changing this setting)

i tried several 23.97fps movies on my pal box and with this option enabled they play much smoother then before.

the movie plays a bit faster then normal (1.042x),
but i dont notice it.

frodo

[Frodo]

dont forget to disable pal60;-)

frodo

[zordon]

whats the harm in adding it if it can be disabled. personally, i would prefer to user this option, hey with the movie playing faster it give me more time for other stuff:-)

[AlCapone]

i would like to suggest this behavior:

when attempting to play 29,97 fps movie on an 25fps system player should say:

---------------------------
you are about to play an ntsc (xx.xfps) movie in pal (25fps) mode would you like to:

a - play as usual (leave me alone)
x - switch to ntsc mode
y - play this movie at ntsc speed in pal mode.
---------------------------

this would make "everybody" happy- of course - this dialog box should also handle user playing pal on ntsc system.

[tslayer]

alcapone,

i think the current way is fine. having an extra popup is a pain. i would just like to click on a movie and have it play right away.

why would you decide that some should be left alone and some should not be? i think most people would be comfortable with the current way of setting the option.

just my 2 cents.

ts

[MrMario64]

this indeed works mighty fine.
super smooth playback.