[Interest] Moving to Qt Mobility

Thiago Macieira thiago.macieira at intel.com
Sun Mar 11 19:05:58 CET 2012

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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