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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