avidemux2.6 "loses" MP4 index

[portal]

A neophyte here, and am at a loss to figure why deletion bolluxes an MP4 file using Avidemux.

Simple problem - camcorder left running after shooting 5 minutes of video so clip the last 17 minutes.

It was intuitive to mark first black frame as A, last frame as B, delete, and File/Save As.

Intuitive to do perhaps, but the results was not as expected. On playback VLC tells me "the AVI file index is broken or missing" and offers to build an index in memory. The file will play with no index, but without any controls.

a) Can I use a different cropping technique of avidemux to delete the 17 minutes without losing the index?

b) Can I use avidemux to build an index after deleting which can be saved with the MP4 so that it will play properly?

c) Should I give up on avidemux and use another editor which will retain/restore indexes for the uncut video?

Thanks in advance for helping out (the avidemux wiki did not help, but then maybe I don't know what I'm looking for).

[hech54]

It was intuitive to mark first black frame as A, last frame as B, delete, and File/Save As.

Use the double arrows (<< - >>) to kind the next KEY FRAME(last frame should make no difference).
Copy
Copy
MP4(name the new file ie xxx.mp4)

[portal]

Wunderbar!

Many thanks for solving my problem. I've got a long way to go, and you have given me a head start.


Thanks a bunch