Frames per second question

[odin24]

Why do some Blus have a fps of 23.976, and some 24... and will this effect playback on a 60Hz TV.

Thanks.

[Ghitulescu]

Why do some Blus have a fps of 23.976, and some 24... and will this effect playback on a 60Hz TV.

23.976 is a so called DF TC (Drop Frame Time Code), while 24 is a NDF TC. I suggest you to have a quick look in google for these if you need more details. 24fps was the standardised movie fps (before was 16fps), while 23.976 came as a result of introducing color on NTSC TV sets.

I'm not sure what do you mean by 60Hz TV, but if you consider NTSC as 60 Hz, there is no problem in displaying both formats (google for TeleCine). BTW, NTSC is 60i in BW but 59.96i in color.

However, if you think of an LCD, here the biggest problem is deinterlacing and not fps, which is oversampled (2x for 60Hz, 3x for 72 and so on). Plasma TVs can do 24p natively.

[neuron2]

BTW, NTSC is 60i in BW but 59.96i in color. Wrong.

[Ghitulescu]

Wrong.

That's correct, but you can elaborate if you think I'm wrong.
Meanwhile, NTSC was 60i because that was the mains frequency. With the introduction of color, this frequency became undesired and they figured out a nice value, 1000/1001, to deviate from it. More info is in History of TV, Wiki, google etc.

[neuron2]

NTSC is 59.94 always, whether the content is color or not.

You first wrote "is", now you're saying "was". I corrected your first statement as it was wrong and may mislead people.

You also wrote "59.96", which is also wrong.

[mpucoder]

This whole thread needs to start over.
Drop-frame and non-drop frame timecodes have nothing to do with framerate, rather framerates which are not integer values can have timecodes expressed in either format. Using non-drop timecode does not alter the framerate (eg NTSC DVDs are 29.97fps, but use non-drop timecode)

23.976fps movies are the result of having been telecined for NTSC, while 24fps movies are the result of a direct transfer. Neither one is missing any frames, but the duration will be different, and the audio may be incorrect in pitch.

As Neuron2 said, NTSC is always 59.94 fields per second. NTSC is the standard which replaced the 60 field/second monochrome standard.

Sony makes LCD televisions which display 24P.

[Ghitulescu]

NTSC is 59.94 always, whether the content is color or not.

You first wrote "is", now you're saying "was". I corrected your first statement as it was wrong and may mislead people.

You also wrote "59.96", which is also wrong.

Sorry about these errors, I have net only at work, and I'm not supposed to use it extensively, so I have to rely on my memory for most facts. Which failed for numbers. You're faster than me in correcting them ...

MPUcoder is right about everything except one, NTSC is not a color standard but a committee - I'm European, so I have to rely on books - one of them, the history of television said precisely that NTSC set the BW system in 1940 or 1941 (I don't recall now, before the WWII) then chose the RCA color system against the CBS one in early 50ies, after the Korean war.

So NTSC was black and white and had 60i.
BW transmissions in NTSC color system are always 59.94i.

And time code is very important, everthing that is muxed, has to have a time code stamp for the decoder to be able to synch two or more streams.