[QLab] caching of video files

[Dan Scully]

Hi-

Interesting thing just happened in tech. I was playing a movie file,
and copied a new version of the file over the existing version. When
I stopped the cue and replayed, it played the old version. "Aha", I
said to myself, "It must be cached or in memory." So I quit QLab and
restarted it, and played the cue. Again the old content. I
eventually had to retarget the cue to the same file to get it to
pickup the new content.

Is that the expected behavior?

Dan Scully

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[ole kristensen]

i suspect that it relates to the way mac os handles file references. the 'handle' given to the software as default actually sees an 'inode' - a unique identifier for the file, which on a lower level rewrites it's destination reference to allow users to eg move files around the filesystem while they are open in applications. and let the app survive accidental file moves.

in your case this would mean that the 'inode' filereference would rewrite itself to the file now in the garbage bin, maybe as an effect of the file being open by an application, ie qLab.

if you emptied your garbage bin, i suspect that it would be clever enough to find the file at it's original location again, but i'm not sure about that.

anyway - there are options for the application coder to override this default behaviour...

just guessing / ole

--
o...@kristensen.name

http://ole.kristensen.name

[Christopher Ashworth]

Hi Dan,

On Dec 5, 2009, at 10:33 AM, Dan Scully wrote:
>
> Interesting thing just happened in tech. I was playing a movie
> file, and copied a new version of the file over the existing
> version. When I stopped the cue and replayed, it played the old
> version. "Aha", I said to myself, "It must be cached or in memory."
> So I quit QLab and restarted it, and played the cue. Again the old
> content. I eventually had to retarget the cue to the same file to
> get it to pickup the new content.
>
> Is that the expected behavior?

No, that wouldn't be expected behavior. Ole mentioned the use of
inodes tracking files as they are moved, but that should apply only
when the file was moved to the trash, not when it is actually deleted/
overwritten.

I'm honestly not sure how it would have played the old content after a
restart if the original file did not even exist anymore---that's
really weird. :/ Which OS version was this?

-C

[Dan Scully]

Snow leopard.

When I get some notes time I'll do some more testing to see if I can
recreate it. Maybe I was mistaken about it existing post-restart.

ds

[Luka Mustafa]

HI Chris,

I can confirm this behavior, I have ran across it only twice in the version 2.2.5. The source files were overwritten, but the content remained unchanged. Than QLab restart did the trick. I can not confirm if the update fixed the problem or not.

Best regards
Luka Mustafa

[Christopher Ashworth]

One thing that *ought* to be useful here is the Refresh Files button
in the toolbar. Worth a shot if you encounter this again.

-C

[Adrian Meier]

I know, this is an old thread but i still have this problem with version 4.4.5.

I can not found any button like Refresh File