In the land down under, live TV is coming in from my TvHeadend server via a mpeg2 codec at up to 1440x1080i@25Hz. There is not a lot of compression with this codec.
This may be unique to the ATV1 with CHD but watching Live streamed mpeg2/VC-1/wmv3 codecs above SD quality would result in a freeze of XBMC and a eventual crash. Recorded 720p and 1080i content played fine. It was just the Live stuff that was an issue.
The FFMpeg update in Gotham for the first time allowed the lowly 1Ghz ATV running Crystalbuntu to decode live mpeg2 (with bob deinterlacing) without crashing. But first you had to manually switch CHD hardware acceleration off.
(As well as post processing)
This fix just bypasses CHD for the above mentioned codecs automatically. No user input required.
Your channel changes / stream freezes will likely benefit as a result.
BTW. If compiling on the Mac is similar to Ubuntu there may be a Compile Cache folder if you have not deleted anything.
All you will need to do is place DVDFactoryCodec.app in the correct folder and run a Configure and Make again.
It should all be pretty quick the second time around, no merging required.