add canvas to portrait in 4/3 relation

[klausj]

dear all,
my TV show only black screen for portrait slides with YUV port.
Now I am going to add a black canvas to all portrait slides by calculating X = Y *4 / 3. However for thousands of existing slides I'd prefer something automatic. It seems that xn only manage a percentage of x or y instead of calculating x in relation to y.
Any ideas?

thank you,
Klaus

[xnview]

dear all,
my TV show only black screen for portrait slides with YUV port.
Now I am going to add a black canvas to all portrait slides by calculating X = Y *4 / 3. However for thousands of existing slides I'd prefer something automatic. It seems that xn only manage a percentage of x or y instead of calculating x in relation to y.
Any ideas?

Yes, currently you can do that, calculating X in relation of Y. I'll try to add it

[klausj]

thanks Pierre; that would be of much help