The mp4 issue with windows is only a problem with old winXP machines, and they are unfortunately still plentiful in the corporate world :-(
I normally always render both mp4 and wmv just to be sure, it just is anther output module anyway so quite easy on my end.
But there is another annoying wmv issue you have to be aware of, when you render a wmv to a server (atleast our servers) there is some wrong flags being written to the file. The "NumberOfFrames" is set to 0, and even if Windows 7 plays the file fine, WinXP wont play it. If you render to a local disk the "NumberOfFrames" is written with the correct value and every version of windows plays it fine. This is ofcourse with the stanard Media Player since that is what most clients use.
download mediainfo to check the file for issues:
wmv does seem to being on the way out, since even Microsoft looks to be promoting mp4 instead now, and there has not been any new versions of wmv in years. I think i saw something about microsoft dropping support for windows XP next year, so soon everybody might need to upgrade to a more current version in the corporate world also :-)
I'm on Macs. I often am sending sample movies to clients. I was under the impression that .mp4 is cross-platform, and viewable by everybody. But occasionally, I get a message from my direct client that his agency or corporate client "can't watch the movie."
This is the point where I would like to say, "That's not my problem." But, my clients think I'm such a genius that I should be able to remotely troubleshoot their issue.
The workaround is often to make them a WMV. I hate WMV, for the record. But, it's an extra step, and I charge by the hour. So, what the heck; I make the WMVs and bite my lip.
So this may be a Q for the Windows people… But, shouldn't anybody be able to play an .mp4?
Unless they're on a 386, or some other quaint computer?
If anybody should have this capability, what are they likely doing wrong?
Note that with corporate clients, they often can't install software. So, telling them to get VLC, etc. could be pointless.