[FFmpeg-user] Converting a 23.98p source to 29.97i ProRes w/interlaced 3:2 pulldown?
barsnick at gmx.net
Mon Oct 26 23:30:30 CET 2015
On Mon, Oct 26, 2015 at 12:06:30 -1000, Mel Matsuoka wrote:
> So is the bottom line that FFmpeg favors overt pedanticism in regards to
> defining frame rates, hence the need for the user to actually provide it
> with the actual math required to define a true NTSC framerate?
No, YOU should be pedantic or precise for your own sake. No good taking
30000/1001 input and making 29.97 out of it (not that the numbers
differ very much). ffmpeg will do whatever you tell it to, for better
Apart from that, making a "more" standard conformant file might just be
better for some cases. Some people tend to use "30" instead of 29.97,
just because it's easier. Apart from the actual frame dupes, I don't
know if e.g. a DVD mastered with that rate is actually fine by strict
OTOH, if your material is any other rate, and you just want to play in
a SW player, I don't see a point in actually *converting*. But when
creating new content, just be precise. My $0.02.
> Is it bad form to simply use the "ntsc" and/or "ntsc-film" aliases,
> instead of using the fractional forms?
In my opinion: Not at all. That's exactly what they're designed and
useful for. (And save you remembering the fractions.)
But this drifted off the original topic: Carl Eugen pointed out that
the output rate of the filter should already be correct, assuming a
correct input rate, so no need to "transform" to 30000/1001 using "-r".
Have you been able to confirm or deny?
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