Mpeg 4 avc/h264 --> avisynth HOW?

[nautilus7]

Is there a tool like DGIndex, but for mpeg 4 avc/h264 streams?

If not, how can i use such video streams with avisynth?

[check]

do you mean raw h264 streams? If so, mux to mp4 with mp4box.
If the h264 is already in a container, just load into avisynth with the following line:
directshowsource("path\to\file.mkv")