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Old October 29th 18, 10:32 PM posted to rec.photo.digital,alt.windows7.general
Paul[_10_]
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Posts: 64
Default Cropping 50 images to the same bottom left corner

George P wrote:
I need to crop 50 Windows screen shots to the bottom left corner.
The initial screen shots were taken with Irfanview on Windows.
I can't do them again as the conditions have changed.
Is there an easy method to crop 50 images using the same dimensions?


If the composition of the shot is not changing,
then Irfanview itself has a batch processor with
crop capability.

if the crop target is moving, and you want to
zoom into some moving portion of the tutorial, you'd
need a different tool flow for that. I think some
video editing tools have had "trajectory" capabilities,
to follow moving stuff. But I've never needed such a thing.

It's important to compose your tutorial shots, so that
the post-editing will be easy. Once I start a tutorial, I
try not to move the focus of the session around on the
screen.

*******

I would never printscreen 50 times. I use FFMPEG and
the gdigrab screen recording capability, and record
video as individual pictures ("A00001.jpg" "A00002.jpg"...).
I've recorded as many as 60,000 images in a single
folder, using FFMPEG for capture.

Then, I use Avidemux 2.5 to walk through the video.
I take the frame count off the bottom of the screen,
then flip over to the folder of images and pull the
corresponding A00xxx.jpg picture. In that way, I only
have to "fish" for the exact images I want. Rather than
processing 50 images and throwing away most of them,
I have a tremendous trove of pictures, and the
time I spend, is the time to locate each desired
image after the tutorial is done. Maybe I only have
to note the frame numbers of five frames, then
go grab the like-named file from its folder for
my uploads.

Avidemux has a crop capability. You could crop the
entire folder of images.

I can even capture a few seconds worth and show an example.
In a Command Prompt window...

cd /d F:\TEMP2 # holds ffmpeg.exe and my images

ffmpeg -framerate 1 -f gdigrab -i desktop -f image2 -q:v 1 -c:v mjpeg a%05d.jpg

Press control-c to end capture.

Then I can capture a particular frame later.

I just made my meta tutorial.

1) setting the crop filter in Avidemux 2.5

crop-filter.gif

https://i.postimg.cc/tg7RCwM2/crop-filter.gif

2) Use Avidemux to open the folder of jpegs.
Set the Crop Filter. Save the entire bucket of frames
as an AVI movie sequence.

Open the AVI file again with avidemux.
Save the (cropped) AVI as a sequence of individual frames again.

In the example, I want the name to be a00xxx style, and I only
have to type the letter "a" for the filename, as Avidemux will
append the unique portion after that.

select-jpeg-sequence-to-save.gif

https://i.postimg.cc/VvPzg6LV/select...ce-to-save.gif

3) Now that I have my second folder of cropped JPGs,
I can go back to reviewing the AVI movie (out.avi), frame by frame.
Here, I think frame 11 captures my point well, so
I note I need picture number 11 from the output folder

preview-the-movie-look-for-candidates.gif

https://i.postimg.cc/nrxt7P38/previe...candidates.gif

4) Here, I've double-clicked a0011.jpg in the crop output folder,
and examine my handy work. It opens in Picture and Fax viewer.
The image looks good, so I'm ready for upload (or something).

verify-cropped-image-is-a-good-one.gif

https://i.postimg.cc/L52rhZs2/verify...a-good-one.gif

HTH,
Paul