This may have already been answered.. but I'm struggling to search for it!
I have a set of images, of varying dimensions that I've created a 'fade affect' with, using imagemagicks convert command.
convert *.jpg -delay 20 -morph 20 %06d.transition.jpg
this generates about 50 images of varying dimensions.
I then use avconv to generate a video..
avconv -r 10 -i %06d.transition.jpg -vcodec libx264 yourmovie.mp4
The problem is, avconv will set the video size as the dimensions of the first image. So if the first image is large, and the second is small, the second will be stretched.
ideally, i want to 'letter box' (i think thats the term?) smaller images so that they're surrounded by a black nothing-ness, maintaining their ratio.
i've tried the -s, but this just stretches ALL the images.
Please help! :(