[FFmpeg-user] Fade in filter and alpha channel fade in text

Paul B Mahol onemda at gmail.com
Mon Aug 13 10:23:26 EEST 2018

On 8/12/18, Joshua Grauman <jnfo-c at grauman.com> wrote:
> Hi all,
> I am combining various effects, and I noticed that when I fade in a video
> using the [in]fade=t=in:st=2:n=24[out] syntax, and I fade in text using
> alpha='if(lt(t,2),0,if(lt(t,3),t-2,1))', that they both fade in roughly at
> the same time, but both are not linear. I'm guessing the fade=in uses a
> sine wave or something to fade in the video, while clearly the text fade
> is based on a linear fading of the alpha channel. Am I correct that the
> video fade in is a sinusoidal fade? Does anyone know offhand how I could
> get the text fade to match the video one?

Fade is always linear in this filter.

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