[Kdenlive-devel] GPU effects?

[Collin Kidder]

Hello, I'm brand new to both KDEnlive and this list. So, I figured I'd
start out with really tough stuff first...

What are the odds of getting GPU based effects? Specifically I'd like to
have hardward motion comp and deinterlacing. Adobe Premiere on windows
can do this. It really makes DV video look a lot better. Eventually
other shader type effects would be nice. I do intend on looking into
this myself but to start me off let me ask this: Should this be done
through an existing framework such as MLT? I think that a range of the
current effects could be done on the GPU. Sepia, black and white,
embossing, etc. Current day 8x and 16x PCI-E cards have plenty of
bandwidth up and down to process 30FPS DV video in realtime.

I tried to search this list for prior discussions on this subject. I did
not find much of anything. Is no one interested in GPU acceleration?

To be clear, I'm not really asking someone else to do it. I'll try
myself. But any pointers toward where to look, what should be possible,
etc would be appreciated.

[Dan Dennedy]

Post by Collin Kidder
Hello, I'm brand new to both KDEnlive and this list. So, I figured I'd
start out with really tough stuff first...
What are the odds of getting GPU based effects? Specifically I'd like to

I am pessimistic about the odds, but the odds don't really matter.
Let's just say, it is not on the near-to-midterm roadmap for any
Kdenlive/MLT developers as far as I know. (I am the MLT lead
developer.)

Post by Collin Kidder
have hardward motion comp and deinterlacing. Adobe Premiere on windows

motion compensation for what - decoding? If so, I refer you to FFmpeg.
They are currently trying to integrate VDPAU patches from NVIDIA. That
might take a while:
http://http.download.nvidia.com/XFree86/vdpau/doxygen/html/index.html

It might be nice to have something more generic, but at least Roman
Shaposhnik, the FFmpeg DV developer is working on a more generic,
comprehensive multi-threading capability in ffmpeg/libavcodec.

Post by Collin Kidder
can do this. It really makes DV video look a lot better. Eventually
other shader type effects would be nice. I do intend on looking into
this myself but to start me off let me ask this: Should this be done
through an existing framework such as MLT? I think that a range of the
current effects could be done on the GPU. Sepia, black and white,

Kdenlive's video filters and transitions come from MLT and MLT's
bridge to the frei0r plugins. There is a project called FreeFrame that
is a plugin interface and set of plugins, some of which are
OpenGL-accelerated. It seems more suited towards VJ apps, but maybe it
will work here. In that case, use the MLT frei0r module as inspiration
for a bridge component to these FreeFrame.

Post by Collin Kidder
I tried to search this list for prior discussions on this subject. I did
not find much of anything. Is no one interested in GPU acceleration?

Definitely interested, but I you know the expression: "you gotta walk
before you can run." I am currently addressing bugs and fundamental
issues with the framework at the moment instead of the modules. Some
of the changes underway are to make it easier to integrate alternative
implementations of image scalers, deinterlacers, colorspace, and
sample format converters that would facilitate your interests. It can
be be done today, but not so cleanly.

Post by Collin Kidder
To be clear, I'm not really asking someone else to do it. I'll try
myself. But any pointers toward where to look, what should be possible,
etc would be appreciated.

Sounds great; go for it!