[Kdenlive-devel] new HEAD

[Jason Wood]

On Sunday 26 Jan 2003 7:12 pm, Rolf Dubitzky wrote:
> This led to some other considerations. You might want to try utils/pplay
> with all kinds of different dv formats (PAL/NTSC/4x3/16x9) and you will
> hopefully see that it not only works, but you also get the correct aspect
> ratio. In case of PAL this doesn't really matter, but in case of NTSC this
> makes a huge difference. Now, kdenlive should not create an XWindow without
> knowing the aspect ratio of the target format. Already now you can request
> a XWindow with specific size. just add width="123" height="345" to the
> <creatXWin..> command,

Urk, no, I don't like this. The window size should not be specified by 
kdenlive, but rather by the user when he resizes the window. Piave should 
automatically set itself to a draw area that works (i.e., maintains aspect 
ratio). Does piave recieve window resize (x11, not VEML) events at the 
moment? If it doesn't, then that is where the problem lies (either that 
kdenlive isn't telling piave to resize the window properly, or that SDL has 
been set up with a fixed window size).

(On a similar note, I am unsure as to why Kdenlive currently doesn't allow you 
to "scale down" the video window, even when the piave instance that was 
contained within it dies. I'm looking into this.)

We may need to add some options - for instance, should the renderer maintain 
aspect ratio? And should the renderer resize to fit the window, or remain at 
a fixed (and specified) resolution? This would be useful for e.g. maintaining 
half-dv image size.

> _but_ it makes no sense to do that before the user
> has specified the target format (or kdenlive knows the aspect of the input
> file it wants to display).

Ok, I can understand this problem, but I consider it unrelated to the problem 
of window size - I think we need a command for "set target format" or "set 
aspect ratio", I think. In the case of the clip monitor, it could vary 
depending on what clip is displaying - consider for example if you want to 
see a 'clip' of a 4096x768.png (say your going to add an effect to it so you 
can pan around it as part of your pal video)? It doesn't make sense to have 
to destroy the video window and recreate it to be able to achieve this, nor 
would you want the aspect ratio to be displayed incorrectly.

> piave uses 4x3 by default and will open a
> windows with half DV PAL size. I think kdenlive can live with that for now
> (will notwork for wide screen, but for PAL and NTSC), but you can prepare
> to change that. I would be cool to have something like "Use
> <some_input_file> format as target format" next to a manual selection.
> <getFileProp..>  returns alread something like:

Yes, this is what I agree with.

>   <stream filename="../samples/4x3-PAL.dv">
>       <container format="rawdv" />
>       <videocodec aspect="1.333333" format="DV"
>                   fps="25.000000" height="576"
>                   system="PAL" width="720" />
>       <audiocodec emphasis="off" format="PCL" frequency="32000"
>                   num_channels="2" quantization="12"
>                   sampling="2" />
>   </stream>
>
> Note that width/height != aspect !

Something I have just noticed : that container "contains" the videocodec and 
audio codec, so can you change the xml to reflect that? i.e. :

<stream filename="../samples/4x3-PAL.dv">
	 <container format="rawdv">
		<videocodec aspect="1.333333" format="DV"
				fps="25.000000" height="576"
				system="PAL" width="720" />
		<audiocodec emphasis="off" format="PCL" frequency="32000"
				num_channels="2" quantization="12"
				sampling="2" />
	</container>
</stream>

> We have to think about how to communicate the render size as soon as we
> have effects. The render size might be different from the source size for
> preview mode (samller -> faster/poorer) .

Ok, I've got a little bit of catching up in Kdenlive to do first though :-)

> Also,  the '-f rgb' option is gone. You can specify the target with the
> <creatWin...> command with <creat...   visual="rgb" >  .  The default is
> "xv" and piave will use rgb automatically if no yuv overlay is available.

Ok, that's good.

Cheers,
Jason

-- 
Jason Wood
Homepage : www.uchian.pwp.blueyonder.co.uk