[FFmpeg-user] Create webm, m4v and swf slideshow of images

[Pascal]

Hi,

I would like to create an image slideshow on the fly with background 
music. As an added bonus I don't know each time I have to create the 
slideshow how many pictures will be in it. I want to embed these formats 
in jplayer so (almost) all different browsers will be able to see the video.

Creating the m4v and an ogv is not a problem. Although with m4v when I 
use the -shortest command for the mp3 background music ffmpeg suddently 
decides to add at least twice the time and plays the second half without 
the music. The image loop is not longer than the music. So that's strange.

When I create webm format the solution for images to stay on screen (-r 
1/5) gives an error. And without that option it works but each 
individual image ofcourse is not visible long enough. Is there a 
solution for this or perhaps a workaround if it's not ffmpegs problem 
but webm?

As I don't know up front how many images there will be in the slideshow, 
is it also possible to either repeat the music if the slideshow is 
longer as well as loop the slides when the music is longer?

I hope someone can shine a light on this and bring me a bit further.

If it is relevant, I use ffmpeg static build by relaxed on Ubuntu 12.04.

Thank you!

Sincerly,
Pascal