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

[Tamas Selmeci]

On 06/30/2010 03:15 PM, Nicolas George wrote:
> Le duodi 12 messidor, an CCXVIII, Tamas Selmeci a écrit :
>> 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...
>
> AFAIK, most DVD editors do not bother to do that. The sound just gets 0.72
> half-tones higher.

Hmmm... not the best, since in my opinion the human ear is rather 
sensitive to such differences.

Here's what I'm going to do:
- video if being recoded at 25 fps, not allowing frame duplication --> 
4% faster video playback;
- audio is being speed up with 4%

So mencoder command line is something similar:
mencoder \
	input.avi -o output.avi \
	-ofps 25 \
	-ovc xvid \
	-mc 0 -noskip \
	-xvidencopts max_key_interval=50 \
	-af scaletempo=scale=1.04 \
	-srate 48000 \
	-channels 2 \
	-oac mp3lame \
	-lameopts cbr:br=128

And now it seems to be alright. One thing I have to examine, the A/V 
sync at the end of a long movie.

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