On domingo, 11 de março de 2012 14.54.14, Daniel França wrote: > Hi, thanks for the answer. > low level functions I mean things like: > get video fps > change things like if a video is showed interlaced, etc > render subtitles on video, etc.
FPS as in "frames per second" does not change depending on interlacing. You
may be confusing frames with fields.
The original TV spec from the United States (standard M) used the electrical
grid's 60 Hz to drive displaying of 60 fields per second. Each field contains
half of the lines, so two fields are required to form one frame, by interlacing
them. That's 30 fps.
In Europe and in other parts of the world where the electrical grid is 50 Hz,
the TVs display 50 fields per second or 25 frames per second.
The 24 fps value comes from the movies, whereas 29.97, 24.975 and 23.976 come
from the previous three frequencies slowed down by 1 frame in 1000, to avoid
intermodulation interference with the colour subcarrier.
In other words, none of those values are relevant today on TV monitors and
digital TVs (LCD, LED, Plasma).
--
Thiago Macieira - thiago.macieira (AT) intel.com
Software Architect - Intel Open Source Technology Center
Intel Sweden AB - Registration Number: 556189-6027
Knarrarnäsgatan 15, 164 40 Kista, Stockholm, Sweden
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