bugbear wrote:
(repost to pick up extra group)

"bugbear" <bugbear@trim_papermule.co.uk_trim> wrote in message
news:zPGdnQwfl9gMNq_VnZ2dnUVZ8j6dnZ2d@plusnet...
Once you get used to them, Virtual Dub (or one of its
extended versions) and/or AviSynth 2.5 provide a free
and often quick method of doing a very large number
of things to "AVI" of various flavors.

They do their magic using "Filters"; both the ones that come
with the programs and the vast number of 3rd party filters
available for both programs.

For just cropping though, you would use the Vdub "Null
transform" filter, and then the "cropping..." button will be
active. ( It becomes active with the other filters as well,
but you only mentioned the crop and this way the video
"Full processing mode" acts more like the "Direct stream
copy" mode.)

1. Load your "AVI".

2. Click on the "Video" tab then on "Full processing mode"

3. Click on the "Video" tab again then on "Filters..." [Notice
the grayed out "Cropping..." button on the right side near the
bottom.]

4. Click on the "Add..." button. [ Ignore the "Load..."
button, that is for adding 3rd party Filters you can download,
to the list. (or your own, if you really get into it)]

5. Scroll down the list and click on "null transform". [ Notice
the description at the bottom.] Now double-click on it and
you will be back at the "Filters" window with the "Cropping..."
button no longer grayed out.

6. Click on the "Cropping" button and adjust the offset boxes
to effect your crop. When you have it the way you want, click
the "OK" button. You should now be back at the "Filters"
window, with the dimensions in the null transform entry now
set to that of your crop. Click "OK".

7. You should now be back in the main window with the original
sized "Input" video display and a gray box the size of your crop
for the "Output" display. Click on the "Edit" tab, then on "Refresh".
The "Output" should now show the cropped video frame.

8. Now you can use the "File" tab and "Save as..." to render your
cropped video to a file. I always render to uncompressed RGB and
use dedicated encoding programs to compress the results.

Luck;
Ken

In message <sIydnao9hK5Usq7VnZ2dnUVZ_r6rnZ2d@giganews.com>, Ken Maltby
<kmaltby@sbcglobal.net> writes
You might notice that he says he's using Linux (fc = Fedora Core), not
a Windows-based OS. VDub and its variants don't run under Linux, and
they are idiosyncratic enough wrt external codecs etc. that producing a
usable Linux executable from the source code is very difficult.

I think VLC has a frame-server option, depending on the graphics card
and its available modes, and that might permit you to get the frame and
save it for processing to identify the bird in question. Alternatively
you could transfer the .avi to a Windows box and use VDub to grab the
frame in question.
--
To reply, my gmail address is nojay1 Robert Sneddon

"Robert Sneddon" <fred@nospam.demon.co.uk> wrote in message
news:WLkyAApm00MIFw5C@nospam.demon.co.uk...
Then this might be the answer as it is touted as a substitute for
VDub, when using Linux;

http://www.videohelp.com/tools/AviDemux

http://fixounet.free.fr/avidemux/

http://www.avidemux.org/admWiki/inde...eo_filter_Crop

Luck;
Ken