You should be able to play any video file that MC on Windows play already.
You can also convert jtv to something else.
When I do that (on my Mac choose to make it a different format in Tools > Options > Media Network > Client Options > Video Conversion), I can't fast forward. In fact, if I try, it goes back to the beginning of the video. Since I'm usually doing this for 4+ hour football games now, that's a rather large inconvenience. On an semi-related note, and one I haven't reported, every time I play a file back like this on my Mac and hit the stop button, MC crashes.
Converting from JTV is a manual process, unless I'm missing something, and takes a long time. To test it out, I just queued up a football game to convert from 1920x1080 to MP4 720p. Perhaps my server is undersized, but it took about 14 minutes to do 5%. That's almost the same time it took to record (4+ hours to convert).
If this process was faster, or less work for me, that would be helpful. But as it is, I don't use those two options.
EDIT: Sorry if this response was more Mac-related than TV related. I picked the TV forum because of the JTV format that seems to be the biggest holdup for me viewing the TV programs on a Mac.
