[kdenlive] Copying Kdenlive projects and Preview Rendering

[Harald Albrecht]

Hi Jean-Baptiste,

good to hear your perspective, as it is very similar to what I tried to 
analyze. I agree that a totally automatic mechanism isn't possible, so I 
see two ways to handle cloning (both may be actually coexisting):

1. cloning from inside Kdenlive as part of the "Save as..." operation. 
In this case I would (hopefully) correctly assume that we should then 
automatically update the document ID as part of a Save-as operation. I 
don't think that we would need an option for this in the save-as dialog, 
but I may be wrong. :)

Adding a clone option in addition to save as has the potential to create 
confusion. While writing this post I asked myself several times whether 
clone creates an independent project, while save-as does not ... or 
would it be the other way round? So I think that keeping save-as is the 
proper way to proceed from here.

2. cloning outside Kdenlive (using a file manager, etc). In case we 
detect that either the location or name of the project has changed 
outside Kdenlive's control then we could ask the user whether the 
project is going to be a new, independing project. With a third "I don't 
understand" that would default to changing the document ID to be on the 
safe side, which wouldn't hurt users anyway.

Option 1. is hopefully a simple thing to do and would be needed anyway. 
Option 2 could act as some safeguard but has also the potential to 
create confusion with inexperienced users as the relocation dialog did 
already in the past. Don't get me wrong: the relocation dialog is fine 
and absolutely required. It's just that the don't-care type of users 
will click it away without thinking, as we've seen in the past several time.

Best regards,
Harald

Am 20.06.2016 um 12:26 schrieb jb:
> Le 20.06.16 à 12:14, Harald Albrecht a écrit :
>> Hi,
>>
>> just want to ask here before filing a bug report: just started work 
>> on two new Kdenlive projects. For convenience, I cloned the first 
>> project in an early stage to be used as the starting point for the 
>> second project. And then I noticed something concerning preview 
>> rendering...
>>
>> 1. While working on the first project, I preview rendered the first 
>> few seconds consisting of the titling for this episode #23. So far, 
>> so good.
>>
>> 2. Then worked on the second project and replaced the title for this 
>> separate episode #24. Now, the fun starts: when preview rendering the 
>> same zone for the titling, Kdenlive happily picked up the preview 
>> rendering from episode #23, which I can clearly see as preview now 
>> uses the wrong titling.
>>
>> So, this brings me to my question: does the document identity 
>> correctly change when I copy a project?
>>
>
> Good question! I also thought about it and have not found a solution yet.
> The project id is created when the document is first created and 
> consists of a timestamp.
> This timestamp is then used to create a temporary folder in 
> $HOME/.cache/kdenlive, and the audio/video thumbnails and preview 
> files are stored in this folder.
>
> This way, the project file can be renamed / moved without losing the 
> temporary data. However if you create a copy of the project (either to 
> try a different edit or to start a new project based on the current 
> one), the document id is not changed, so the same temporary folder is 
> used, leading to potential conflicts of preview files (but on the 
> other hand it can be nice to have the audio/video thumbs already 
> created).
>
> I cannot think of a way to automatically handle this...
>
> Maybe we could introduce a "clone" feature that would set a new 
> document id and copy temp data to that new folder ?
>
> Any idea/comment is welcome.
>
> jb
>
>> Best regards,
>> Harald
>>
>> PS: As always, doing actual projects on the bleeding edge...
>
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