[MEncoder-users] 23.976 --> 25 fps conversion problem

[Tamas Selmeci]

On 06/30/2010 02:42 PM, Grozdan wrote:

>> Is there any way I can produce 25 fps movie output from 23.976 fps material
>> with frame interpolation/appropriate telecine/pullup? -vf pullup did not
>> solve my problem. That annoying "stop" in movie flow must not be present at
>> all.
>
> Not with mencoder. You can do the reverse (eg, 25 ->  23.976) but not
> what you ask. There are no filters/ways current to do that with
> mencoder

That's a pity...

> also note that -mc 0 *completely* disables the mencoder A/V sync algo,
> so the probability of having sync issues increases (dramatically in
> some cases)

Yes, I also saw it in the manpage.

>> (My rescue idea is to recode video at 25 fps without frame duplication, thus
>> the movie duration will decrease by ~4% [23.976/25], and the audio is
>> resampled at a 4% higher frequency to keep A/V sync)
>
> This is a very common used technique, even by major studios. They just
> speed it up

A 1-hour movie lasts ~2.5 minutes sooner with this technique, this is 
not that dramatic speedup that a spectator would realize. However, I'd 
like to resample audio to keep the pitch... mencoder refuses to resample 
my input at 50050 Hz (+4%):

-af resample=50050:1:2 -srate 48000

so I'll have to use other tools too.

Regards,
-- 
Selmeci, Tamas
http://www.open-st.eu