[FFmpeg-user] Using ffmpeg to blur moving objects

[Francois Visagie]

> -----Original Message-----
> From: ffmpeg-user [mailto:ffmpeg-user-bounces at ffmpeg.org] On Behalf Of
> Boris T
> Sent: 01 November 2016 22:47
> To: FFmpeg user questions
> Subject: Re: [FFmpeg-user] Using ffmpeg to blur moving objects
> 
> Hello,
> 
> Thanks for the reply.
> 
> An example use case of what I'm trying to do is to blur faces in a video.
> I've already managed to detect the areas I want to blur, now I'm trying to find
> the most efficient way of doing it.
> 
> When using this type of command:
> [0:v]crop=160.00:160.00:94.40:96.00,boxblur=10[
> step0];[0:v][step0]overlay=94.400:96.00:repeatlast=0:enable=
> 'between(t,0.073,7.55839409433962)'[step0_overlay];
> 
> The first part:
> [0:v]crop=160.00:160.00:94.40:96.00,boxblur=10[step0]
> creates the blur over a 100 x 100 area of the video.
> 
> And then the second part:
> [0:v][step0]overlay=94.400:96.00:repeatlast=0:enable='between(t,0.073,7.
> 55839409433962)'[step0_overlay]
> applies it.
> 
> I assume what you're suggesting Cley is to have a completely separate tool
> do the blurring?

If you're doing (limited) motion blurring for aesthetic purposes as opposed to completely obscuring moving parts, the Avisynth QTGMC() filter does exactly that with high accuracy (and built-in motion detection).

>
> Thanks!
> 
> 
> 
> 
> 
> On Tue, Nov 1, 2016 at 3:40 AM, Cley Faye <cleyfaye at gmail.com> wrote:
> 
> > 2016-10-31 15:23 GMT+01:00 Boris T <boris.t.richard at gmail.com>:
> >
> > > Yes, I already have the moving objects' coordinates (x, y values,
> > > the
> > box's
> > > width and height, as well as the duration of the blur). I only need
> > > to
> > use
> > > ffmpeg to blur that object in the video according to the provided
> > > coordinates. I have a working solution, but it becomes very slow the
> > > more blurred overlays I have.
> > >
> >
> > ​I am not sure I'm getting the whole picture of what you're doing, but
> > if you have a lot of blurring to do on each frames, maybe a script
> > that output each video frames into another tool doing the blur, which
> > in turns output into a second ffmpeg process for transcoding could
> > avoid you a cascade of overlays.
> > _______________________________________________
> > ffmpeg-user mailing list
> > ffmpeg-user at ffmpeg.org
> > http://ffmpeg.org/mailman/listinfo/ffmpeg-user
> >
> > To unsubscribe, visit link above, or email
> > ffmpeg-user-request at ffmpeg.org with subject "unsubscribe".
> >
> _______________________________________________
> ffmpeg-user mailing list
> ffmpeg-user at ffmpeg.org
> http://ffmpeg.org/mailman/listinfo/ffmpeg-user
> 
> To unsubscribe, visit link above, or email ffmpeg-user-request at ffmpeg.org
> with subject "unsubscribe".