[Kdenlive-devel] Notes for renderer window design

[Stephane Fillod]

Thu, Mar 01, 2007 at 06:42:33PM +0100, Juan M skribis:
> - First of all, I think it's a great idea to use ffmpeg as renderer engine.
> For me is the best !

Indeed, even though stability of releases is an issue. 

> - I do not think we need to let the user choose between PAL & NTSC when
> rendering. This information is already in the project settings, so take it
> from there. If the user is working in PAL and decides to change to NTSC for
> rendering (or viceversa), then only he needs to do is changing project
> settings.
> 
> - For the same reason, I do not think we need to take care about fps.

Good idea.

Should the metadata be defined in the project properties (but
overridable in export window) ?

> - The first decission for the user is where & what he wants to render. He
> needs to select the location (dir) to place the file and the filename (no
> need for an extension. Should be automatically added). Also he needs to

Could the export folder default to the project folder?

> decide if want to render video+audio, only video or only audio. And if he
> wants to render the full timeline or just a part (based on selection or
> marks)

I like the current ability to export zone (selection/guide).


> - This info should be in the main window. Render option (Video+audio, video
> & audio) should be tabs that will include their own parameters.
> 
> - Once in the selected tab, the user should have the choice to select a
> "template". In ffmpeg terms this should be a target type. We should define
> the most usual (DV, DVD, SVCD, MPEG, ...) and if the user select any of
> them, the rest of parameters will be defaulted.

Juan, what you think of the existing profiles of Kdenlive? I agree with you,
there should be more. Can we make a list?

> - If the user do not want to select a template or want to change something,
> we'll have also the most usual options in the screen. For me, they are:

Are you refering to the current Export tab "customize"?
It works pretty well, but I still have a problem to set the video bit
rate. It looks like it is not taken into account by ffmpeg, even though
MLT get the right values (I traced it).

> - Video: Codec to be used, size, aspect, number of pass, video bitrate, min
> & max quantization (for VBR fans. Maybe also min & max bitrate ?)
> - Audio: Codec to be used, frequency, audio bitrate and no. channels

Some help text about the advanced paramters would be helpful.

> - For the rest of options, we may have an "Advanced options"  part, but I do
> not think it's necessary if we follow next point.
> 
> - For advanced users, I think the best option is to have an additional tab
> where they can select the preferred encoder (mencoder, ffmpeg, transcode,
> ...) (is it possible to work with different encoders in kdenlive ?) and then
> pass the rest of options they want as a parameter list for this encoder.


Can it be made possible to render two videos at the same time? 
In most of my projects, I have to render 2 versions, one in Flash
with low quality (for Internet download with low speed) and one
version in PAL for people with high speed download. Right now,
I do it with ffmpeg/avidemux. MLT should be able to have 2 consumers,
that would be a convenient feature of kdenlive, factorising
the producer and effect stack.

In the eye-candy departement, that would be cute if the export progress
bar could also appear in the KDE task bar when kdenlive is minimized.
That would allow the user to know when to stop playing frozen-bubble
because then rendering completed :)

-- 
Stephane