[MPlayer-users] please help test my mplayer widescreen converter wrapper script

[Daniel Manjarres]

On 7/2/06, RC <rcooley at spamcop.net> wrote:
>
> On Sat, 1 Jul 2006 21:13:48 -0500
> "Daniel Manjarres" <danmanj2 at gmail.com> wrote:
>
> > Cool, but not a complete solution.  I have files at "4:3" which are
> > letterboxed with VERTICAL bars too.
>
> On a widescreen display, pan&scan would work perfectly for removing
> those.



Would that work for a non wide-screen display? I wrote this script in a
general enough way that it also works for 4:3 screens.


> I have ntsc video captures that have a "black" level _above_ a
> > cropdetect threshold of 35.
>
> How are you capturing these?  I've done literally thousands of files
> over the past few years, and none have had any problems.  In fact I use
> a threshold of 30.



I am not capturing them, they are histrocial files off the internet, that I
can't find anywhere else. Basically people's vidcaps off of 10-20 year old
VHS tapes. I have a choice of manually permanently re-equalizing them, or
making a script that is smart enough to deal with them, and then use
playback picture controls. By my way of thinking re-equalizing them would be
cheating, since I want 100% coverage, and they make a great example case of
gray letterbox bars.


> Let me rephrase: It samples an adaptive number of frames at 5
> > different points in the file adaptively selected according to the file
> > length.
>
> Still, it's quite easy to script cropdetect to do that.


Ok, now do it with white letterbox bars and I'll be happy. Honestly, right
now I am more interested in the video signal processing needed to do this
correctly 100% of the time than the mechanism of how it gets done. Hopefully
eventually it can be done right in mplayer instead of through a script, and
it will run much faster.


> The part of the script that is brittle is the crop detect.
>
> Speaking of which, a round parameter of "1" won't work.  2 is the
> minimum.  Few formats can be cropped to odd dimentions.


Oh yeah, It was 2 before, but crop detect outputed a y size of 404 and a y
offset of 2 for a file with a height of 405 (404 + 2 = 406, 406 > 405) so it
wouldn't play, so I changed it to a round of 1 with -zoom to make it work on
that file. Of course that file is a shock music video that I don't like and
was going to delete but now I have to keep it around now as a test case.


> Even if it crashes mplayer it will still at least play,
>
> Same here (scripting cropdetect).


I am curious about your script, why don't you post it so I can try it out?
I would be surprised if it worked on ALL of my files, but it would be
interesting to see how much time getting the last n% to work has cost me. I
am specifically curious about negative crop detect paramaters. If the sample
point in the file is all black I get negative y size and x sizes, which
mplayer will NOT play, so I catch that case and reset them to the movie size
if they are negative, do you handle that case, or is there some paramater to
force cropdetect to not print crazy numbers?