Achim, George - thanks for the quick and useful tips.
We were able to get it working with some experimentation : instead of using
MovieImporter with external timebases, instead we used the normal timebase but
took the output image and stored that with a Sample & Hold patch, after which
the movie is effectively no longer in the active patch chain. Doing this, we
don't see the movie load failures, and performance is great. I don't know why
this alternative method works and the other method doesn't, but there seems to
be a lot of voodoo when doing QC programming.
On Jun 23, 2013, at 12:11 PM, George Toledo <gtole...@gmail.com> wrote:
> In addition to Achim's advice -
>
> For this kind of thing it can sometimes be good to activate the down-sampled
> image for a moment, inside of a render in image patch with feedback rendering
> enabled, and then make sure that chain is no longer evaluating once the color
> buffer was filled with that image (sometimes this might require feeding a
> blank string to file paths or careful multiplexing/demultiplexing). That
> allows the texture to stick around with a minimal amount of patches
> processing.
>
> On Jun 23, 2013, at 2:59 PM, Achim Breidenbach <ac...@boinx.com> wrote:
>
>> Hello Michael,
>>
>> 1) AFAIK the movie patch is only triggered if it's inputs are changing,
>> because of performance optimization. If you put in always the same "Patch
>> Time=0" it only gets called once and so it is just able to call QuickTime to
>> to load a movie, but this won't render it yet. You should be able to
>> "jiggle" the patchTime=0 with some really small random number (+/-0.0001
>> secs), so that QuickTime don't has to load a new frame, but gets always
>> called on each render cycle in QC. (To do so use a Random patch and a
>> Math-patch to add the random number to the pathTime you are feeding into the
>> Movie Importer)
>>
>> 2) Since there is no correct error message (error null) we can't be sure
>> what this means. However it could be the explanation why you don't see an
>> image at the first (and only) render cycle.
>>
>> 3) When a movie gets loaded QuickTime is preparing a lot of media data in
>> advance in order to have some frames already in the buffer. This may take
>> some time (too much to load 12 movies simultaneously). It may lead to a time
>> out for movie loading trying to keep QC alive.
>>
>> 4) Just a guess: If this "loading load" from issue 3 is causing a time out
>> then in the next render cycle QC tries to load the movies again, maybe with
>> the same timeout again. And finally keeps timing out every loading of the
>> movies for ever.
>>
>> My suggestion: Is it important that the movie thumbnails are present very
>> quick when you start the composition? If not, you can try to develop a
>> composition that steps through the files list, selecting one movie file
>> after the other, just using one movie importer to read in one thumbnail at a
>> time. You may use a "Que" patch to store those images in a structure. If you
>> have a structure of thumbnails it may be a lot easier with an "Iterator"
>> patch, to display all those thumbnails with a dynamical count. For playback
>> you will need to have two more movie importer patches (which makes three in
>> total regardless of your movie count).
>>
>> best,
>>
>> Achim Breidenbach
>> Boinx Software Ltd.
>>
>>
>> On 23.06.2013, at 17:01, Michael Diehr wrote:
>>
>>> We have an QTZ composition which scans a folder using DirectoryScanner for
>>> movie files, and loads each movie file into a MovieImporter patch, using
>>> external timebase with time set to 1.0 seconds. This is to present a
>>> static "thumbnail" of the movie file to allow the user to choose which
>>> movie they want to play back.
>>>
>>> We've discovered a number of issues with this and are looking for
>>> tips/advice/help:
>>>
>>> * Issue 1 - PatchTime: When MovieImporter.PatchTime does not change, the
>>> movie will not display at all. For example, if MovieImporter.PatchTime=0,
>>> nothing shows up on the billboard. If you then change
>>> MovieImporter.PatchTime to 1.0, then the movie will display: however, the
>>> frame that shows up is from time=0.0, not 1.0. So the bug seems to be
>>> "MovieImporter with external timebase, image displays only after PatchTime
>>> changes, and then only shows the prior time"
>>>
>>> * Issue 2 : Errors - for some reason, we get a bunch of error messages in
>>> the log. I'm not sure if this is related to Issue 1 or not. The errors
>>> look like this:
>>>
>>> Quartz Composer[12282]: *** Message from <QCQuickTimePlayer =
>>> 0x7fe2b97535f0 "QuickTimePlayer_1">:
>>> Failed retrieving image from movie <QTMovie: 0x7fe2b7439990 time scale =
>>> 2997, duration = 60000, rate = 0.000000, tracks = { 0x7fe2b76ae0e0 }>
>>> (error (null))
>>>
>>> * Issue 3 : Load Failures : in a simple composition where there only a few
>>> movies, it works fine. However, when we make it much more complex (e.g. 8
>>> banks of 12 movies) then there appears to be some sort of timeout problem:
>>> some of the movies load, some of them don't.
>>>
>>> We also see these errors, possibly related:
>>>
>>> WindowServer[117]: CGXDisableUpdate: UI updates were forcibly disabled by
>>> application "Quartz Composer" for over 1.00 seconds. Server has re-enabled
>>> them.
>>>
>>> * Issue 4: Variable Performance : Sometimes, the composition loads all the
>>> movies normally, and will happily play at a solid 60fps (this is with 2
>>> banks of 12 thumbnails displayed, 2 movies selected and playing in
>>> billboards, and one billboard which mixes the 2 movies with some simple
>>> effects). Other times, it bogs down to 30fps or even lower. There
>>> appears to be some correlation between performance and Issue 3 - when some
>>> of the movies didn't load, then performance was worse.
>>>
>>> This is all tested under the latest version of QC: 4.6 (148) Framework 5.1
>>> (284). The movie files are all PhotoJPEG 640x480 short duration loops (1
>>> to 20 seconds long).
>>>
>>> Any ideas?
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>>
>>
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