[vorbis] Video codec

[Bob Miller]

Chrissy and Raul wrote:

> >Likewise, we're not worrying that 30 fps isn't really 30 fps in NTSC
> >video?
> 
> The difference is small enough to not be a problem.

It would be a problem if your video is sync'd with audio.  After only
sixty seconds, a 29.97 Hz video played at 30 Hz will be 60 msec ahead
of the sound track.  That's enough to make a talking person's lips look
unsynched, I think.  (A 90 minute movie would be 5 seconds out of
sync.)

May I sugest using the DDA algorithm (used to draw diagonal lines in
2D graphics) to calculate frame repeats (or skips) anytime the source
frame rate doesn't exactly match the output device's rate?  It's
extremely fast, and it's exactly accurate if the ratio of frame rates
is a rational number.

-- 
                                        K<bob>
kbob at jogger-egg.com, http://www.jogger-egg.com/

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