libav and ffmpeg based stuff, maybe with compile flags off? Getting away from directshow might be the only way to get newer code, which stands to be faster.
I get surprisingly good performance from a core2duo running MPV from deb-multimedia, on Debian. 1080p h264 is nearly all fine, just the odd scene that slows down. But a SS7? I guess MPEG2 at DVD levels might be possible with good software, otherwise it'd have to be the pirate style of the time: 1/4 DVD size, as a DivX.
Otherwise, there is no insane graphics card that can help? Though the Radeon in the machine mentioned above has worse h264 decoding than in software.