[Ffmpeg-devel] swscale/img_convert confusion

Luca Abeni lucabe72
Tue Oct 3 09:46:07 CEST 2006

Hi Richard,

On Tue, 2006-10-03 at 10:00 +1000, Richard Khoury wrote:
>  In the year 2006, of the Month of October, on the  2th day, Fred Rothganger wrote:
> >    How about write a version of img_convert() that calls swscale 
> > appropriately?  That way, no-one needs to check anything.  This may 
> > sound like bloat, but if it is simple to handle, then the bridge 
> > function costs very little in library size.  If it is complicated, then 
> > the library really should provide a bridge.
> > 
> This was the solution I had in mind. If img_convert() can be set up to
> wrap swscale when configured in, then the interface will remain the
> same and I'll be able to compile my program against pre-swscale and
> post-swscale versions of libav* libraries.
My first implementation worked in this way. But this solution would
create a dependance of libavcodec on libswscale that we want to avoid
(if I do not need pixel format conversion or rescaling, I must be able
to link libavcodec without linking libswscale, even if it has been
compiled with --enable-swscale).

> The most important thing
> for me is that I can't guarantee if the user of my code will have an
> ffmpeg version compiled with swscale or not, and I need to make my
> software compatible in both cases.
As I said in my previous mail, you do not need to know if it has been
compiled with libswscale or not... You just need to look at the library
version (ok, the version has not been increased yet, so this currently
does not work... But it will be properly increased as soon as swscale
integration will be considered stable enough).

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