That's what I found.
For those video files that DOpus can calculate, you have to give it time to work out what is going on. How long it takes depends on the number of files involved. And video files are big, so need time.
Not all video files work. Just AVI.
If DOpus cannot show the "Duration" if you set the folder format to Movies, then, as you would expect, it doesn't seem to be able to calculate the total playing time for the files in the folder.
Hmm... Not sure what is going on there.
Give this status bar config a try; it's what I use and seems to work for me at least:
{i:dir} {sd} / {td}
{i:file} {sf} / {tf}
{h!} <#FF0000><b>{hi} hidden</b></#> {h!}
{h!} {smp3} /{h!}{h!} {tmp3} {h!}
{sba} / {tba} {rpad}
{busy}
{ls}
{fl}
{h!} {df} {bg+w=50,f=2,c1=#68f040,c2=#f06840,g=0}{h!}
Oh, one other thing:
What you're seeing could be explained by Flat View being turned on. (If Flat View is on, calculation of the duration for the status bar may only happen if some other thing, like an info-tip, forces the calculation. This is done to avoid causing thousands of files to be inspected, or having to have special Status Bar configs for Flat View that avoids the duration calculation.)
Make sure Flat View is turned off, like this:
Thank you, I've tried it but I get same problem, it seems my computer doesn't want to work with video files 
Instead of showing 00:00 I get this:
(Broken image link)
I have flat view off like you.
What happens if you select all of the files at once? (i.e. Ctrl-A)
But still selecting videos I get 00:00 (with your script I get total time of the folder):
If you switch to Details mode and turn on the Movie -> Duration column, what's it show for all the files?
I can see the duration of all Avis 
:
And still 00:00 in the status bar when you select some files in details mode with the duration column showing?
Nope, it works fine in detailed view. The problem is with list view 
.
I can confirm this.
10.0.1.0.4185.x64
My default is Details view. I pick a folder and I see total times filled in. I switch to List view and I can still see total times. If i select some files, I get times for selected and total times (I have both in my config... "{smp3}/{tmp3} (Selected/Total)"). If I refresh the page while in List view, total times goes to 00:00 and I can't get it back unless I switch to Details view. Selecting files also remains 00:00
Here's my status bar:
{i:dir}{sd}/{td}
{i:txt}{sf}/{tf}
{h!}<#FF0000><b>{hi}hidden</b></#>{h!}
{sba}/{tba}
{smp3}/{tmp3} (Selected/Total)
{rpad}
{h!}FREE: {df} {bg+w=50,f=2,c1=#68f040,c2=#f06840,g=0}{h!}
{ls}</#>
{fl}I think is a problem with List view only, because with Thumbails and Tiles it works well. I only get the problen with List view.
I cannot reproduce the problem here, even in list mode:
Ok 
Thanks anyway for your help
My guess is that the background thread which calculates the lengths of the files is getting stuck sometimes.
The calculation depends on video codecs, and some (versions of) some codecs can go wrong (or simply take a long time) on certain files. That could also explain why I don't see it on my machine (as I probably have different codecs).
This is just a guess, though. It could be something else that I haven't thought of, maybe tied to a configuration option somewhere. It does not seem to be List mode by itself, though. (There was an issue with List mode behaving this way but it's been fixed for quite a while now.)
I don't have video codecs installed because I use VLC Media Player which has built-in codecs, maybe that's the problem? However in other view modes it works fine, so it is strange.
@platanos
As an additional or optional or alternative method to display audio file durations in the status bar i've just(!) created a new DO10 button with
cd C:\Programme\TagRename
@async:C:\Programme\TagRename\TagRename.exe {sourcepath}
The software has a fine status bar which i wasnt able to reproduce with DO10 commands. DO10 status bar displays durations of some audio file formats (e.g. MP3) but not all (e.g. APE, FLAC, WMA, etc.). My media collection consists of all kinds of file formats (M4A, MP4, AAC, WMA, MP3, FLAC, APE, MPC, OGG, ..) that's why the DO10 status bar isnt of much use on my PC. So on your PC you may want to think of creating a button too (Tagnrename was just a suggestion because it's a well-known and popular music file tagger).
i havent tried your status bar code so i cant tell if it etc. i am happy with my button and my motto is "Dont touch a running system." 
Thanks Plunder, does it work with video files? I'm interested in AVI files because I have many videos in my computer. If it works I'll give it a try 
Every machine has video codecs installed. 
Windows comes with some, programs you install may add some, etc. even if you don't explicitly install any yourself.
(If there were no video codecs, Opus wouldn't be able to inspect the files at all.)