Hello Mathieu and Boris,
1) Sometimes I get those artifacts when not using a "Clear" patch even if any
of the other Billboards and Sprites are rendering full screen. When you don't
clear the buffer you are rendering in first, it could be that there is some
texture garbage with z-buffer garbage in it. This happens when the graphics
card rearranged its memory blocks. The "Clear" (don't forget to set it up to be
rendered first ;-) ) will erase the destination buffer and make sure that in
every render cycle it looks the same.
2) Of cause the CoreImage kernels are rendered in the GPU. Only in some rare
cases QuartzComposer decides to render something on the CPU (e.g. some core
image code can't be processed by the used GPU). Then it falls back to software
rendering which causes the frame rate dropping dramatically. I am sure you
would notice this too. If you are getting the memory issues within your
application you can use Instruments to monitor the memory usage and drill down
to the very object which allocated the memory blocks.
best,
Achim Breidenbach
Boinx Software
On 27.03.2012, at 11:35, Mathieu BEN wrote:
> Hello Achim,
>
> I'm joining the discussion as I've been working on this issue with Boris.
>
> Actually we've been facing 2 problems with Quartz Composer:
>
> 1. The first one was something like 'ghost' images appearing in a composition
> frame where images from a QuickTime source movie were rendered. The rest of
> the composition is made of still images representing banners, logos,
> illustration images, etc.. . The QC composition is quite complex and the
> total number of rendering patches (Sprites or Billboards) reaches 15 and even
> more (more than 15 levels of overlayed images).
> We use the QC composition in a Cocoa application with a QCRenderer
> initialized 'off-screen', and we write images (NSImage objects) from the
> source movie (via a QTMovie object) on a published image input of the
> composition. Then we call the snapshotImage: method of the QCRenderer to get
> ouput images from the composition and put them in an ouput QTMovie.
> As explained, we sometimes (not always) have 'ghost' images appearing in the
> output movie, in the frame where the source video is rendered. This ghost
> images randomly and sparsely occur (3 or 4 times per minutes of generated
> video), and they correspond to other images used in the composition (banners,
> logos,..), always appearing in their original side, color, orientation, etc.,
> so they may correspond to input image buffers, substituing an output
> buffer... . Furthermore, these ghost images usually appear in groups of 3 or
> 4, each separated from the following one with a single 'expected' source
> movie image.
> We had no memory leak issue with this setup, only 'ghost' images
>
>
> 2. The second problem was the one explained by Boris: to by-pass the first
> problem of 'ghost' images, we tried to reduce the number of rendering modules
> (sprites and/or billboards) in the composition and using Core Image filters
> embeded in the composition to do the image compositing (image overlay). We
> tried 2 things for that : 1) simply using a CISourceOverCompositing filter in
> the 'edit filter function' of the Core Image Quartz Composer patch. 2) coding
> the following Core Image kernel in the CI QC patch :
>
> kernel vec4 coreImageKernel(sampler bckImage, sampler topImage)
> {
> vec4 bckPix, topPix;
> topPix = sample(topImage, samplerCoord(topImage));
> bckPix = sample(bckImage, samplerCoord(bckImage));
>
> return topPix + (1.0 - topPix.a) * bckPix;
> }
>
>
> Both of these solutions did the overlay work correctly but both lead to a big
> memory leak, in particular with HD source movie images, rendered in HD ouput
> images: in this case the 24 GBytes of our MacPro was eaten in a few tens of
> seconds, while our Cocoa application doesn't use more than 1,5GBytes of
> memory (according to the activity monitor of the Mac).
>
> My hypothesis is that Quartz Composer actually does the image compositing in
> GPU when using the rendering patches like sprites and billboards, but that
> Core Image filters embeded in a QC composition does not, thus working in RAM
> and causing the observed memory leak.
>
> I have no idea now how to do our compositing work with these to issue, wich
> really look like bugs in Quartz Composer...
> Any suggestion would be appreciated.
>
> Best,
>
> Mathieu
>
>
>>> De : Achim Breidenbach <ac...@boinx.com>
>>> Objet : Rép : Quartz Composer memory leak
>>> Date : 27 mars 2012 09:28:04 HAEC
>>> À : Boris Rousseau <boris.rouss...@powedia.com>
>>> Cc : quartzcomposer-dev@lists.apple.com
>>>
>>> Hello Boris,
>>>
>>> in my experience QuartzComposer does all the graphics processing in the GPU
>>> not in the CPU. If your RAM goes up, this is usually caused by the inputs
>>> you are using. E.g. a H264 video has a big memory footprint. Can you
>>> describe in more detail, what your composition does and what sources are
>>> you using? What does "suddenly" mean to you (after certain seconds,
>>> randomly)?
>>>
>>> best,
>>>
>>> Achim Breidenbach
>>> Boinx Software
>>>
>>> On 27.03.2012, at 08:42, Boris Rousseau wrote:
>>>
>>>> Hello,
>>>>
>>>> I am facing a memory leak while using Quartz Composer to process and
>>>> generate videos.
>>>> Quartz Composer starts processing the video in HD starting from 700Mb and
>>>> suddenly raises over the RAM limit until the Mac Pro swaps.
>>>> Apparently, the issue is probably link to Core Image processing while
>>>> converting or rescaling images to HD but I am not sure about it.
>>>>
>>>> Did anyone already have this problem, please ?
>>>> How do I debug Quartz Composer memory leak, please ?
>>>>
>>>> Thanks for your help.
>>>>
>>>> --
>>>> Boris Rousseau
>>>> <Pièce jointe Mail.png>
>>>>
>>>> 12A Avenue des Peupliers
>>>> 35510 Cesson-Sévigné, France
>>>> fixe: +(33) 2 30 96 12 83
>>>> mobile: +(33) 6 19 12 65 54
>>>> www.powedia.com
>>>>
>>>>
>>>>
>>>>
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>>
>
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