[FFmpeg-devel] [RFC] libmpcodecs libavfilter wrapper?

[Stefano Sabatini]

On date Tuesday 2010-11-02 12:55:11 +0100, Michael Niedermayer encoded:
> On Tue, Nov 02, 2010 at 12:06:37AM -0400, compn wrote:
> > On Tue, 2 Nov 2010 02:00:24 +0100, Stefano Sabatini wrote:
> > >The problem with libmpcodecs is that it isn't a library, and was never
> > >meant to be usable from outside MPlayer, so trying to integrate it
> > >into FFmpeg is a nightmare. Indeed the only way is to copy the files
> > >to FFmpeg and all the dependencies (vf.h, mp_msg.h, help_mp.h,
> > >m_option.h, m_struct.h, img_format.h, mp_image.h, mpc_info.h, vfcap.h
> > >etc) and somehow patch it to the build system...  and yet I have no
> > >idea how I can map the MPlayer log system to that of FFmpeg and looks
> > >more that I can withstand...
> > 
> > (note that i have no idea what i'm doin and to take this mail as a
> > joke)
> > 
> > probably start small:
> > s/mp_msg/av_log
> > s/MSGL_ERR/AV_LOG_ERROR
> > etc, then you can cross off mp_msg.h
> > 
> > s/MSGTR_OpeningVideoFilter/"opening video filter"
> > etc, then cross off help_mp-en.h
> 
> the obvious way:
> 
> #define mp_msg
> #define MSGL_ERR 0
> #define MSGTR_OpeningVideoFilter ""
> ...
> 
> (if there is no header that satisfies these without introducing new unresolved
>  dependancies)
> 
> 
> and once one or 2 filters work, one can look at changing these things to more
> reasonable things
> 
> iam not aware of any real issue in libmpcodecs for porting it but as said
> it needs someone with a bit more experience in such porting, aka this is
> probably not a good case for ones first such project

I already told that libmpcodecs is not a library but just a bunch of
files scattered through a dir and so writing a wrapper around it is
nothing which can be done without much pain, better is to redesign
libmpcodecs but we have already such a redesign and is called
libavfilter.

So from my point of view it would be just better (and easier) to make
libmpcodecs implement a filter for libavfilter so that we can compare
a libmpcodecs filter with a libavfilter port.

Then in the long term it would be just better to make MPlayer directly
use libavfilter and drop libmpcodecs filter support. This is not my
idea but I believe this was implicitely decided three years ago when
you choosed to design libavfilter from scratch.

This unless you want to maintain the same code in two separate
projects (and libmpcodecs cannot be used by other applications, which
is not the case for libavfilter) which looks to me just A Bad Idea
(TM).
-- 
FFmpeg = Friendly and Fancy Monstrous Peaceful Excellent Geisha