--- On Sun, 4/8/12, Ichthyostega <[email protected]> wrote:
From: Ichthyostega <[email protected]>
Subject: Re: [CinCV] Confused about ffmpeg -vf crop=h:w:x:y
To: [email protected]
Received: Sunday, April 8, 2012, 10:50 PM
Am 09.04.2012 03:43, schrieb Murray Strome:
> I think the scale has to come before the crop (at least this worked, whereas
> when I tried it before with the crop before the scale, the crop was
> completely ignored).
As I wrote you: it was ignored, because we (both) used the wrong syntax.
Append all filters separated just with comma, and they won't be ignored.
Of course you can scale first if you like; in this case, obviously, you must
base your numbers for cropping on the size of the already scaled image, not
the input size. And also (obviously) you're wasting work (you calculate scaled
pixels just to crop them away). In many cases this won't matter much, though.
Cheers,
Hermann
PS: did the command line I wrote you work as expected?
Hi Herman,
Thanks for your help. You are correct, I can (and should) put the "scale=..."
after the crop. Using the WinFF command as a template, I have now done
something a little differently, which is more efficient and seems to work very
well. I now import the video directly from the DVD without copying the .VOB
files to the Hard Drive. This is the form of the command that I last used quite
successfully (once I had done a cd to the directory where I wanted my
{OUTPUT_FILE} to be located:
cat /media/DVD*/VIDEO_TS/VTS_01_1.VOB /media/DVD*/VIDEO_TS/VTS_01_2.VOB
/media/DVD*/VIDEO_TS/VTS_01_3.VOB /media/DVD*/VIDEO_TS/VTS_01_4.VOB | ffmpeg -i
- -vf crop=iw-0-0:ih-64-64:0:64,scale=720:480,unsharp -aspect 16:9 -b 8500k -g
12 -trellis 1 {OUTPUT_FILE}.mpg
I don't completely understand the -trellis option; I have looked at lots of
descriptions of this encoding but don''t really understand it well enough to
know if it offers any advantage. Since WinFF put it in, I decided to include
it. It does not seem to hurt anyway.
Since I am making a standard NTSC DVD, the 1028X720 was really overkill, so I
don't really need it. I have tried the "unsharp" for the first time, to see if
it makes the video any sharper.
I understand the -g option, but probably do not need it.
My first few attempts at this seem to be producing good results so far.
Now on to figuring out how to use Cinelerra and other LINUX tools to do my
editing etc. in LINUX so I do not have to resort to Pinnacle Studio in
Windows!!!
Thanks again for your patience and assistance.
Murray
