The effect of changing framerate isnt quite that straightforward, as most web formats use temporal compression. Instead of each frame being compressed in full, only keyframes contain the full image info. The frames that arent keyframes, just contain info about what has changed since the previous frame. This can be a highly effective technique, and means that how often you have keyframes will likely determine the necessary bitrate more than your frames per second will.
This is one reason why I have always suggested people try experimenting with higher framerates in their vlogs, dont assume that it will make the compression articfacts twice as bad if you double the framerate, or that you need to make the bitrate twice as high to compensate for having twice as many frames. Nor should twice the framerate automatically be assumed to require twice as much CPU power, battery power etc to decode. Its also another example of Apples advice differing from the historical advice given by most in this group. Apple have never recommended using 15fps but thats often been the advice here. Certainly I couldnt declare 'everyone should use 25 or 29.97 or 30 fps' because 15fps is going to work better for some under certain circumstances, there is no 'right answer' although I expect higher framerates will become the norm eventally, as most portable devices can handle them ok there is no hardware barrier to this, more perception than anything else) Cheers Steve Elbows --- In [email protected], "Bill Cammack" <[EMAIL PROTECTED]> wrote:Your only way > around that is to encode at a lower FPS so that you retain quality at > the expense of smooth, fluid motion, say, coming down from 30 fps or > 29.97 to 15fps. That way, you could get twice as much data per frame > because you're outputting half the number of total frames in the same > amount of time.
