Black field when switching movie

voxdeserti's picture

Hi everybody! The thing what I'm trying to struggle with now is when I have Movie Importer and switch between videos Quartz blackens for a while all rendering data - even front layers. It is not good because when I want to switch video in background mode (kind of VJ software simulation) the effect of that switching is still visible...

Do you have any ideas to make Quartz to switch between videos smoothly?

(Video chain: Directory Scanner>Structure Index Member>Structure Key Memeber>Movie Importer>Billboard)

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cybero's picture
Re: Black field when switching movie

I'm assuming first of all that you aren't wanting to view one entire movie and then play another in its entirety.

What about using a Multiplexer patch and switching the source index, either by number or a named index system?

See attached example.

I hasten to add, I couldn't reproduce your problem. I found the two movies I used switched quite seamlessly for me.

See if this still reproduces your problem, in which case, I'd ask are you using a .mov or .mp4 or other that has a keyframe for each frame? Adds to the size of the file, makes for much smoother running, which is what my .mov filess were [ProRes codec, and not an H.264 [bundled frames]].

Oops - just realised I'd not attached the requisite exemplar. [better late than never?]

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switchmoviesimplex.qtz29.48 KB

jrs's picture
Re: Black field when switching movie

I'm not 100% clear on what you mean - can you post a composition?

The attached composition is what I use to solve what sounds like a similar problem and may help - you might need to adjust the alpha of the backing colour if you want to see things behind the current rendering layer.

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fix blank images.qtz3.5 KB

voxdeserti's picture
Re: Black field when switching movie

Here' s a comp. Set Time in input parameters to 1 and specify movies folder. Then switch movies by left/right arrows. You'll see blacking instead of shader image is present.

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Xfadesample.qtz47.72 KB

voxdeserti's picture
Re: Black field when switching movie

It means that Quartz blackens viewer window while loading a movie.

shaker08's picture
Re: Black field when switching movie

maybe you can fix it with kineme video player ... for me work fine

jrs's picture
Re: Black field when switching movie

The dissolve patch need two images which it doesn't get for a frame or two during the changing of the movie - you could use the patch I posted before to make sure its always getting an image or just use two billboards and some alpha like in the attache comp

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Xfadesample-fixed.qtz49.44 KB

voxdeserti's picture
Re: Black field when switching movie

I see the difference but still switching a movie freezes shader's frame. It is just strange that every simple vj software does it smoothly and Quartz doesn't...

gtoledo3's picture
Re: Black field when switching movie

So where are you at with this? Are you using Video Tools? Are you using the Video Player that was pointed out, and looking at the patch info/setting Frame History Size and Cached Files per the patches instructions for when one wishes to vary play rate?

(edit: I keep mixing this up with the other thread about 3D fractal movies, but the sentiment is similar though you aren't varying play rate)

A shader compiles on the fly; if there's no image present at the input and it needs one, it will turn off. When it gets info at all of the inputs, it stays on. You may be doing something that keeps image from outputting one of the patches for a moment, so that the whole shader is restarting. If you programmed it so that there's an image present + you handle the buffering of your video correctly + the machine isn't underpowered, and this likely will not be a problem.

Another thing that may help, may not, is for you to place your file paths in a multiplexer set to "string" instead of searching for them with a Directory Scanner.

boya's picture
Re: Black field when switching movie

If you do not need sound you can get switching working seamlessly in you turn of Asynchronous mode. If you need sound, try running that in a separate file.

Running from an SSD you will have no visible delay.