[vlc-devel] transcode vfilter

[Paul Corke]

I'm having problems getting the transcode module to use a
vfilter that I specify.  I'm actually using my own "video
filter2" module, but the issue can be replicated with
"ripple".  I have an sout chain like this:

#transcode{vcodec=mp2v,vb=6000,acodec=mp2a,ab=192,venc=ffmpeg,vfilter=ri
pple}

The module_Need() function finds the filter and gives it a score
of 10000 because the shortcut matches.  It also finds the "scale"
module which has a default score of 10000.  Because there are then
two modules with the same score, for some reason it tries to load
"scale" even though that is not what I specified as my vfilter!

I think there are four ways to fix this:

====== modules/video_filter/ripple.c ======

-    set_capability( "video filter2", 0 );
+    set_capability( "video filter2", 1 );
     /* and make the same change to all other modules */

====== modules/video_filter/scale.c ======

-    set_capability( "video filter2", 10000 );
+    set_capability( "video filter2", 9999 );

====== src/misc/modules.c ======

                        /* Found it */
                        if( c && c[1] )
                            psz_alias = c+1;
-                        i_shortcut_bonus = i_short * 10000;
+                        i_shortcut_bonus = i_short * 100000;
                        goto found_shortcut;

====== modules/stream_out/transcode.c ======

                id->pp_ufilter[id->i_ufilter]->p_module =
                    module_Need( id->pp_ufilter[id->i_ufilter],
-                          "video filter2", p_sys->psz_vfilters[i], 0 );
+                          "video filter2", p_sys->psz_vfilters[i],
VLC_TRUE );

======

I think I prefer the final option, because it has no impact on
the other parts of the system.  By setting "b_strict", it forces
the selection of the specified module and I can't see why anyone
would want it to choose a different one.

Options 2 or 3 might be interesting in case the same thing is
happening elsewhere - someone else might know and I don't currently
have time to look at all the module_Need() calls.  Therefore
I'm attaching a patch file for the final option.

Regards,

Paul.
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