[FFmpeg-devel] Read this if you are porting filters from MPlayer

[Stefano Sabatini]

On date Monday 2010-12-06 17:17:58 -0500, Daniel G. Taylor encoded:
> On 12/02/2010 09:46 PM, Michael Niedermayer wrote:
[...]
>  3. Modifications are sadly not as simple as you've led them on to be.
>     I'll use as an example here the modifications I've tried to make to
>     the scale filter to prevent the following from happening:
> 
> $ ffmpeg -i foo.flv -vf scale=320:-1 -vcodec libx264 -vpre fast out.mp4
> ...
> [scale @ 0xa890710] w:390 h:240 fmt:yuv420p -> w:320 h:197
> fmt:yuv420p flags:0xa0000004
> [libx264 @ 0xa8954c0] width or height not divisible by 2 (320x197)
> ...
> Error while opening encoder for output stream #0.0 - maybe incorrect
> parameters such as bit_rate, rate, width or height
> 
> As you can see it still happens in trunk, was reported months ago,
> has several working patches to fix it, but has been going back and
> forth forever with no end in sight and feature creep like you
> wouldn't believe.

I rememember that thread and if you can illustrate what's the problem
with your fixes I'll be happy to try to help. There are still many
integration problems with libswscale/scale, I delayed further work on
that partly due to the frustration of working with two distinct repos
(FFmpeg vs libswscale), waiting for the git transition.

> I don't mean to push my issue here but I mean to
> illustrate that working with FFmpeg is frustrating, especially if
> you only try to contribute occasionally, and especially if you are
> only allocated a small amount of time at work to do so.
-- 
FFmpeg = Faithless and Faithful Marvellous Portable Erotic God