On 2018-11-01 15:02, S Andreason wrote:
Jim DeLaHunt wrote:
.
I want to generate an overlay to zoom in, have the input png start
small, and grow to half the video size, like from 20 to 320 in
width. Starting the zoompan at z=0.1 does not seem to work.
Take a look at the *pad* filter
<http://ffmpeg.org/ffmpeg-all.html#pad>. That generates an output
frame which consists of an input frame with padding around it.
I suppose that could work, if it would accept the frame number as a
variable, so that the x,y,w,h could change over time, and allow the
padding color to be transparent.
So, I still see no filters to start small, without disturbing the rest
of the frame, and have it grow over time to full size, replacing the
video on the lower layer.
I see the problem. The *pad* filter doesn't let you use the frame number
/n/ as a parameter for expressions defining /width/, /height/, /x/, and
/y/. In contrast, the *zoompan* filter does give you both an input frame
number and output frame number to use in expressions. I have used
*zoompan* to animate a video by writing ridiculously complex expressions
for /x/ and /y/ and /zoom/ based on frame number.
You have confirmed zoompan won't shrink less than 1.0 in size factor.
For example zoom value of 0.1 should enlarge the input stream x10 and
with x and y I could select where in the stream[0] to place the
(growing/shrinking) stream[1].
I have the impression that *zoompan* was designed with one use in mind,
panning over a large still image, and so they missed the chance to make
a more flexible and useful tool. I would love it if someone would make
an "animate" filter, which could do arbitrary affine coordinate
transforms on frames of an incoming video, based on a set of key frames,
with bézier interpolation between the keyframes.
That tool would sure serve my needs better. Maybe it would serve yours
also. Should we raise money for a bounty to write it?
Also if the first filter was successful, I need to crop it so that
it grows over time. I am having trouble getting crop to adjust based
on the frame number. From my testing it seems n in this case starts
at 0 when the enable between starts, instead of the output video
frame number like the other filters I have been using.
I'm not sure I follow what you mean by "when the enable between starts".
Sorry, I'll re-word it;
when the "enable='between(t,#,#)'" begins
I was experiencing something more than just 0 to 2 frames offset. I'll
work up another example once I have a moment to re-create it.
Thank you. That phrase is much clearer when accompanied by punctuation.
Sorry, I've never used the /enable/ parameter, so I don't know what
effect it has on other parameters.
Best regards,
—Jim DeLaHunt, software engineer, Vancouver, Canada
_______________________________________________
ffmpeg-user mailing list
ffmpeg-user@ffmpeg.org
http://ffmpeg.org/mailman/listinfo/ffmpeg-user
To unsubscribe, visit link above, or email
ffmpeg-user-requ...@ffmpeg.org with subject "unsubscribe".
--
--Jim DeLaHunt, j...@jdlh.com http://blog.jdlh.com/ (http://jdlh.com/)
multilingual websites consultant
355-1027 Davie St, Vancouver BC V6E 4L2, Canada
Canada mobile +1-604-376-8953
_______________________________________________
ffmpeg-user mailing list
ffmpeg-user@ffmpeg.org
http://ffmpeg.org/mailman/listinfo/ffmpeg-user
To unsubscribe, visit link above, or email
ffmpeg-user-requ...@ffmpeg.org with subject "unsubscribe".
