[Kdenlive-devel] External Video rendering

[Marco Fleckinger]

Hello,

On 11/12/12 19:05, Dan Dennedy wrote:
> On Tue, Dec 11, 2012 at 2:26 AM, Marco Fleckinger
> <marco.fleckinger at wikipedia.at>  wrote:
>> Is it possible to export a melt command line from a kdenlive
>> project, so I could render the project also on another machine
>> without needing to install a graphical user interface?
>
> You can save a render script, but that uses kdenlive_render, which
> is little more than a wrapper around melt for some special things
> like making dual pass appear as one job. You do not really need it.

AFAIK not.

> Basically, you can just render the kdenlive project file directly
> with melt.

Just had a look at such a file and found out that it's indeed looking like

http://www.mltframework.org/bin/view/MLT/MltXml

So <kdenlivedoc /> will be ignored by MLT? As there are just some very
small thumbnails and other small files in the thumbs directory the
project-file is referring to, I assume that those are just for the work
with kdenlive?

> The kdenlive render script will show you the melt avformat parameters
> for the encoding after kdenlive has done some variable substitutions
> based on project and render dialog settings.

Ah, you mean the output-profile I would use with melt's consumer? Here I 
have a problem on Debian Wheezy: The profile "OGG/Theora" doesn't work. 
I have to replace several parameters. So instead of

"Theora/Originalversion": acodec=libvorbis aq=3 vcodec=libtheora vq=8 
vb=1024k r=25 aspect=%dar pass=%passes

I needed to use

-acodec vorbis -aq 3 -vcodec libtheora -strict experimental -sameq -vb 
1024k -r 25 %1.ogv

when I worked with ffmpeg/avconv. Even compiling ffmpeg from the sources 
didn't work. I didn't know what aspect=%dar means, therefore I didn't 
use it at all in my tests.

But actually it is not possible to change this profile permanent at all. 
At least I could find out how to do so yet. I'm really new to 
video-processing but am locking from a IT-view on this. This helps a lot.

It'd also be really great to help webm and vp8 to get more popular, but 
I couldn't find a default profile for it.

> Thus, you can prototype it in kdenlive, make a render script, and
> then copy the parts of the render script for your own custom
> melt-only script.
>
That was actually the idea: Prototyping in kdenlive using small 
resolution video files. The final resolution will be rendered on a 
server or workstation somewhere in a data-center with better internet 
connection. So many people can work with the same files distributed.

> Please be aware that not everything works in a typical headless
> configuration. Things like kdenlivetitle and SVG loading require the
> QtGui module that does not work without an X11 session, but you can
> use the xvfb virtual X11 server!
>
Hm, actually it should run on a server machine, maybe I could arrange 
that somehow. Otherwise I need to generate the videofiles containing the 
results of this routines by using other ways.

>> WikiTV-Team
>
> intriguing project name
>
Yes, since the preparations for the 10th anniversary of Wikipedia on 
January, 15th 2011 there is also a WikiTV project forming. It should be 
a sister project to Wikipedia as e.g. Wikibooks, Wiktionary, etc. We 
also cooperate with a guy from the ORF (Austria's national broadcaster).

As we want to support Free Knowledge, we also think that recording Open 
Source talks are relevant for us, as well as some Wikimedia Events. At 
the moment we only operate in the German-spoken area, but would also be 
glad if this was more international.

Less than 6 persons we're looking for people who'd like to join us.
So if anybody is interested into this project, we would welcome you to 
join us!

There is also a strong reference to Linux and FOSS. The two main people 
visiting different events operating for WikiTV are Linux-Users including 
me :)

Marco