[Pkg-scicomp-devel] Bug#487638: opencv FTBFS

[Ludovico Cavedon]

Nicolau Werneck wrote:
> So let me list some facts, and please tell me if I forgot something,
> or if I got anything wrong:
> 
> 1_ The whole problem started because OpenCV uses some function in
> ffmpeg that became obsolete after i-don't-know-what version.

yes, opencv isusing the img_resample API that after at a while being
deprecated has been removed from the ffmpeg library. Applications should
use the swscale API instead. Unfortunately I do not know more details
about that :(

> 3_ Debian has some restrictions regarding ffmpeg, and the official
> version has a number of relevant modifications from upstream. Many
> Debian users opt for the bootlegged ffmpeg package instead.

I do not think this is affecting opencv. official debian ffmpeg has been
removed of mpeg4-based encoders. The rest should be the same.

> 4_ Everything should work fine with a certain Debian SVN version of
> ffmpeg and a certain other Debian OpenCV package.

Yes, a part from the fact that right know the build of opencv on sid
would fail because of the missing API.

Actually I realized that this is not a correct FTBFS. If you build the
package as is it will not fail. It will be build without video support
because the new version of ffmpeg changed the include paths. If you fix
the paths, *than* it will FTBFS because of the wrong API. I was to quick
in tagging it as FTBFS, feel free do reduce severity.

However without video support the package is useless for me, because I
am using it.

> What I still don't know exactly is:
> 
> 1_ Does any Debian package of ffmpeg already implement this new
> functions from ffmpeg, or are we still holding to the deprecated
> mechanism? Or are we keeping both by any chance?

I know qutecom, for example, had this problem and is now using the
swscale API for video.

> In other words: Does the "Debian way" today means using the deprecated
> functions (img_conv)? If so, when are we going to make the switch to
> the more recent mechanisms?

I think we need to patch opencv to use the new API. Looks like bug
487638 has a patch...

Thanks for the attention,
Ludovico