Fps settings

Question

*for the sake of this debate let's say I download a video that was originally set at 30fps and want to run it at 60p fps, my understanding is that if I just run it at 60p fps then frames will be added.*
120Hz refresh rate
The digital display technologies (LCD, plasma, DLP, LCoS, etc.) that have replaced picture tubes are progressive scan by nature, displaying 60 video frames per second — often referred to as "60Hz." HDTVs with 120Hz refresh rate employ sophisticated video processing to double the standard rate to 120 frames per second by inserting either additional video frames or black frames. Because each video frame appears for only half the normal amount of time, on-screen motion looks smoother and more fluid, with less smearing. It's especially noticeable viewing fast-action sports and video games. This feature is available on an increasing number of flat-panel LCD TVs.
*Now, let's say I take the video into photoshop cs4 add frames then export it to QT and save at 60p fps will it still add frames or will it run the frames it has at 60p fps on my apple cinema screen?*

Answer 1

for the sake of this debate let's say I download a video that was originally set at 30fps and want to run it at 60p fps, my understanding is that if I just run it at 60p fps then frames will be added.
If you simply "run" it at 60 fps, then nothing is added and the clip will play twice as fast in half the time of the original. On the other hand, if you export/re-compress the file using normal routines such as found in the QT Pro Player, each frame of the original clip will be duplicated and play back at twice the original frame rate but retain the original playback duration.
Now, let's say I take the video into photoshop cs4 add frames then export it to QT and save at 60p fps will it still add frames or will it run the frames it has at 60p fps on my apple cinema screen?
It would likely depend on what you started with (30p fps or 30i fps), what you are doing (field doubling, 'tweening, frame duplicating, interleaving black frames, adding subliminal messages/images, etc.) and the work flow used to "mix/merge" your results (motion clip, still image sequence, etc). Basically, if the source to be sequenced already has a time reference that equates to something other than 60 fps, then it will add or drop frames as needed to comply with your export target fps. If manipulated as a sequence of stills, then you are free to select an fps that will add the proper timing reference equivalent to 60 fps assuming you have added the proper number of new/duplicated/modified frames in proper sequence.