[MEncoder-users] duplicate frames - shortening video?

[Lobster]

On 5/06/2012 11:01 a.m., hans at netupgrades.com wrote:
> Hi -
>
> Videos are being shortened (losing frames?).
>
> My source video is a desktop recording of me scrolling down a web page,
> and I wait for a few seconds each time before I scroll down further.
>
> I think mencoder is optimizing these "similar" frames and drops them.
>
>
> I have tried many variations to keep my long scroll pauses intact:
>
> mencoder out.ogv -audiofile myfile.mp3 -ovc lavc -oac mp3lame -fps 5 -o
> test.avi
>
> mencoder out.ogv -audiofile myfile.mp3 -ovc lavc -oac mp3lame -fps 15
> -o test.avi
>
> mencoder out.ogv -audiofile myfile.mp3 -ovc lavc -oac mp3lame -fps 15
> -vf harddup -o test.avi
>
> mencoder out.ogv -audiofile myfile.mp3 -ovc lavc -oac mp3lame -vf
> harddup -o test.avi
>
> These are the type of messages I see:
>
> 1 duplicate frame(s)!
> Pos:  10.9s    151f (93%) 16.10fps Trem:   0min   2mb  A-V:-0.133
> [1406:210]
>
>
> Each time, I see duplicate frames being dropped, and my video is a very
> fast scrolling down the web page.
>
> I thought -vf harddup made it not lose frames?
>
> How do I keep the same video length as my source file?

use -ofps to force the output frame rate.
I.E `mencoder out.ogv -audiofile myfile.mp3 -ovc lavc -oac mp3lame -vf 
harddup -ofps 15 -o test.avi`