mpeg-2 decoder. What determines which one is used ?

[davexnet]

Hello, I've been playing with my capture card and captured two short 1920/1080 clips.
They're both mpeg program streams.

When I open the first with Gspot, it tells me Directshow would play it with the Intervideo (Windvd)
that I have installed.

On the second file, gspot tells me that Directshow would use the mainconcept decoder. (which was installed
by Sony Vegas I think)

The windvd decoder has the higher merit. Both files seem to have the same attributes,
why is directshow choosing a different decoder for each ?

[El Heggunte]

why is directshow choosing a different decoder for each ?

Actually, it was Gspot itself, and not DirectShow, that determined
how the respective playback graphs should be built.

Applications can be smart/stupid enough to choose which filters will be used
for audio&video decoding. Sometimes their "free will" will not produce good results
(or any results at all). Graphedit does not have to have the same choices as
Gspot, WMP 6.4, or Media Player Classic.

[davexnet]

Except when I played it in WMP 10,
view/now playing/show media info/right click name/properties
confirms that indeed, the very codecs Gspot predicted
Directshow would use, are actually being used in WMP.

So my original question still stands unless I'm misunderstanding something.