[FFmpeg-user] How to drop every Nth frame?

[Andrey Aleksandrovich]

Sorry to You, my fault.
All is working now.

On 9/21/13, Andrey Aleksandrovich <andrey.aleksandrovich at googlemail.com> wrote:
> I am sorry but it doesn't cut any frames at all.
> ffmpeg -y -i original-5614-frames.avi -filter:v "select='mod(n,24)'"
> out.avi
>
> The original video is 5614 frames and the output video is 5614 ones.
> I expect that output must be 5381 frames (I need to cut/drop 233
> frames - every 24th from 5614).
>
> On 9/21/13, Sam Logan <shapableline at gmail.com> wrote:
>> On 9/21/13, Andrey Aleksandrovich <andrey.aleksandrovich at googlemail.com>
>> wrote:
>>> oh, thanks, but I can't understand syntax of select filer:
>>> Example from manual:
>>> # select one frame every 100
>>> select='not(mod(n,100))'
>>>
>>> But how to set - "select 23 frames every 24"?
>>
>> mod() is the modulus function. So mod(n, 100) returns positive for any
>> value of n except for multiples of 100, so Boolean negation of that
>> will return false for everything except multiples of 100, thereby
>> selecting one frame per hundred. So to select 23 frames per 24, do:
>>
>> select='mod(n,24)'
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>