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

[Paul B Mahol]

On 9/23/13, Andrey Aleksandrovich <andrey.aleksandrovich at googlemail.com> wrote:
> I also try:
> -filter:v select=mod'(n,372)',crop=in_w-20::11:,scale=320:240
> but it's the same
>
> [Parsed_select_0 @ 0x543d35fc90] [Eval @ 0x3bd5b30b370] Missing ')' or
> too many args in 'mod(n'
> [Parsed_select_0 @ 0x543d35fc90] Error while parsing expression 'mod(n'
> [AVFilterGraph @ 0x543d2dfed0] Error initializing filter 'select' with
> args 'mod(n'

You need to add '\' after every ',' in expressions.