Tried tourette's patched tsreader.ax and it doesn't atleast work for mpeg2 -> mpeg4 avc switches. After channel change you just get black picture. And following loglines:
2008-07-29 17:27:31.296875 [Debug][MPMain]: TSReaderPlayer: waiting for vmr9 connection
2008-07-29 17:27:31.500000 [Debug][MPMain]: TSReaderPlayer: no vmr9 connection. Maybe we have a radio recording but expect video too so we suppose it's ok.
With same tsreader.ax the ATI MPEG Decoder works (from ATI AVIVO package).
From IRC "[17:26] <@tontsa> but it shows for mpeg4 video mpeg2"
So most likely the TsReader bug that causes mpeg4 to be reported as mpeg2 needs to be solved before we can remove the ffdshow from blacklisted codecs.