Change ratio of titles

Hi

I shoot in PAL 16:9 but I did not pay attention and I did a projet in PAL 4:3. Only after I saw the black bands.
I changed the project preferences. All went well for videos, but the titles are flattened... And when I edit one, it tells me it was not created in the correct format, but does not propose to change the format.
The problem is that I have more than one hundred titles (subtitles).
How to fix this without retyping all the titles ?

Thank You

It would be interesning to add a function "change the format of the title". Isn't it ? (or change automaticaly...)

I just tryed to fend for myself...
I edited the project with gedit and it seemed that each title was written as:

<kdenlivetitle width="768" height="576" out="125" LC_NUMERIC="fr_FR.UTF-8">
<item z-index="0" type="QGraphicsTextItem">
<position x="45,91304347905795" y="434,2173913120772">
<transform>1,0,0,0,1,0,0,0,1</transform>
</position>
<content font-color="255,255,255,255" font-outline-color="0,0,0,255" font-pixel-size="23" font-italic="0" font-underline="0" font-weight="75" font="DejaVu Sans" font-outline="1,2">Vengo en bicicleta desde Alaska
y así llegué a Nicaragua.</content>
</item>
<startviewport rect="0,0,768,576"/>
<endviewport rect="0,0,768,576"/>
<background color="0,0,0,0"/>
</kdenlivetitle>

Then, after a bakup, I changed all the lines :

kdenlivetitle width="768" height="576" out="125"

by:

kdenlivetitle width="768" height="432" out="125"

and all :

768,576

by:

768,432

When I open a title, I still have the error message, but the text is not flattened.
I just put back the texte over a dotted line that has appeared and the text is again correct in the preview.

I did a test export : no problem, the subtitle is good.

I'm happy because that's a lot less work than retype everything...

But, is my hack seem reliable for you ?

Can I count on ?

Thank you.