Hi Thiago, I know that, I need the fps because it's for a subtitling application. I've to set the subtitle in the right frame, advance frames, etc. the interlaced stuff was only an example, I know it has nothing to do.
On Sun, Mar 11, 2012 at 3:05 PM, Thiago Macieira <thiago.macie...@intel.com>wrote: > 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 > > _______________________________________________ > Interest mailing list > Interest@qt-project.org > http://lists.qt-project.org/mailman/listinfo/interest > >
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