[Kdenlive-devel] image clips improvements

[Carsten Pfeiffer]

On Saturday 30 December 2006 19:23, jb wrote:

Hi,

> I just checked and in fact the streched resizing is done by Kdenlive. By
> default, MLT proportionally resizes the image, which is of course probably
> better.
>
> Kdenlive adds an "aspect_ratio" parameter to the image producer so that it
> is streched to completely fill the project's frame size. (you can find this
> in docclipavfile.cpp line 383 for clips showed on the clip monitor and in
> clipmanager.cpp line 599 for the timeline clips)

Indeed. Simply removing those calls makes it work pretty nicely. The images 
are scaled properly and have a black background. Are you going to remove 
these in SVN?

> When MLT resizes the image, it does not fill the borders with another
> color. Instead it creates a video clip with the image size.
> Let's say you have an image with size 200x576, the resulting image clip
> will keep this size. The problem is that if you attempt to make a push
> transition between a normal clip and this image clip, you will get weird
> results since the transition movements are defind in % of a frame.

Hmm, I couldn't notice any problems in the transitions I tried. It all looked 
good.

> The best solution would probably be as you suggested to offer an option in
> the MLT image producers to fill the borders of an image with a definable
> color. If you want to have a look, there are 2 main image producers in MLT:
>
> pixbuf found at: modules/gtk2/producer_pixbuf.c and
> qimage found at: modules/qimage/producer_qimage.c

I hacked the qimage producer for a start but it seems to me that mlt still 
resizes the frame, as it automatically inserts a "normalizing" resize filter, 
which calculates an appropriate frame size based on producer (image size) and 
consumer (output size) (in filter_resize.c). That way, the qimage producer 
always gets a request in refresh_qimage() with a width and height that are 
different from the output size. So it can never create an image of the output 
size, e.g. to fill the background in black.

Cheers,
Carsten