Problems with H.264 mpeg-4 AVC in Sony Vegas

[Chaobunny12]

I have a video encoded with H.264 AVC, and Sony Vegas won't play it. Vegas recognizes that a video stream is there, but the video is all black.

Gspot gave me the following information:

Codec: avc1
Name: H.264/MPEG-4 AVC
Status: Codec Status Undetermined

What does codec status undetermined even mean?

I have ffdshow installed, and from what I've gathered searching google ffdshow should support that codec. Help please. =3

[Kariudo]

Don't edit with H.264/MPEG-4 AVC

Use vdub to make clips, and encode those with huffy/lagarith/utvideo...or something like mjpeg so you can bait n' switch...or something like Pismo File Mount & AviSynth Virtual File System so you can import scripts into vegas