Le mardi 29 novembre 2011 20:19:16, Dan Dennedy a écrit : > Christophe, if you are interested in continuing to work in this area, > perhaps consider to make a GEGL plugin for MLT as it is continuing to > build on its usage of OpenCL: > http://libregraphicsworld.org/blog/entry/gegl-developer-sponsored-to-improv > e-hardware-acceleration-support
Hi Dan, I have a lot of video shots stored, waiting to be edited. So yes, i'm still interested :) My first task is to learn openCL. Unsurprisingly, the spec looks quite similar to openGL. So i expect the same benefits and the same caveat, ununified memory. So even with this solution, we would still have to stay as much as possible on the same rendering path (until unified memory comes to real life). As soon as possible, I will make some openCL bench to compare to openGL. After that, i will look deeper into gegl, but a first look makes me think that its tile based design does not map very well to openCL. And i don't think that we are interested in 16/32bit in video world where you finally render to yuv420 :) > On Mon, Nov 14, 2011 at 1:49 PM, Dan Dennedy <[email protected]> wrote: > > On Mon, Nov 14, 2011 at 12:23 PM, Christophe Thommeret <[email protected]> wrote: > > > Hi, > > > > > > First, thanx for this great work, I'm using MLT with the Kdenlive > > > frontend to edit video (mainly avchd) and it does its job quite well. > > > But even with low res video (i use kdenlive's "proxy clip" feature), > > > adding a simple effect like contrast makes the preview to drop frames. > > > I sure don't have the strongest cpu around but i think a E8500 is not > > > so bad. > > > I've recently played a bit with opengl and found that a simple nvidia > > > GT220 can run several glsl filters (say 6, like > > > contrast,brightness...) on a 1920x1080, while still displaying 50fps > > > (deinterlaced 25i) ! So you can imagine what could be done on lowres ! > > > Having a flawless preview is really comfortable :) > > > > > > I see that opengl is in MLT's todo. So i wonder if you have already > > > some thoughts on what should be done and how it should be done. > > > I would be happy to help. > > > > There is already a WebVfx plugin that supports GLSL via JS in > > QtWebKit's WebGL. Recently, I added a shader for YCbCr-to-RGB color > > conversion for the OpenGL output in a new project I am working on, and > > I see its benefit. > > > > In general, it seems difficult and costly performance-wise to fit GPU > > effects into the framework unless you use them entirely. Otherwise, > > you end having to do some on the CPU and also keep the full > > flexibility and expression of arbitrary filter ordering. Also, one > > should consider OpenCL and how either can be combined with hwaccel > > decoder output in vendor-independent VA-API, which is still not > > integrated. I am not willing to lend much effort to a NVIDIA-only > > solution. Also, my experience with VDPAU shows it gets tricky to keep > > things stable when you combine it with multiple video tracks, > > transitions, and parallel processing, which is why it is not enabled > > by default. > > > > I am slowly learning more about where I want to go with this, but not > > aggressively. Feel free to contribute. You might want to contribute > > VA-API integration or improve upon VDPAU to get started. Once you want > > to move into filters, we will need an image type to represent a > > surface or PBO and its converters with the other image types. > > > > -- > > +-DRD-+ > > -- > +-DRD-+ -- Christophe Thommeret ------------------------------------------------------------------------------ All the data continuously generated in your IT infrastructure contains a definitive record of customers, application performance, security threats, fraudulent activity, and more. Splunk takes this data and makes sense of it. IT sense. And common sense. http://p.sf.net/sfu/splunk-novd2d _______________________________________________ Mlt-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/mlt-devel
