Simple editing of VBR H264 files

[Rishtonite]

Complete novice here!
Starting using IP CCTV cameras and have some 1 hour long (3GB) video files. I'd like to do a simple edit, e.g. delete start and end leaving just a few minutes worth of video.
I tried AVIDemux but trying to open a file it reports - cannot find a demuxer.
Also, an attempt to open a .avi file also failed.
Searched Google and this forum but not found a solution or alternative software.
Would welcome suggestions...
Thanks

[davexnet]

Open the file in mediainfo view>text and provide the info here in this thread

[Rishtonite]

Hope this is what you are asking for...

Complete name : \\QNAP212P\Public\cctv\h264 files\113-20170517-0147.h264
Format : AVC
Format/Info : Advanced Video Codec
File size : 1.58 GiB

Video
Format : AVC
Format/Info : Advanced Video Codec
Format profile : Main@L4.2
Format settings, CABAC : Yes
Format settings, ReFrames : 1 frame
Format settings, GOP : M=1, N=50
Width : 1 920 pixels
Height : 1 080 pixels
Display aspect ratio : 16:9
Frame rate : 12.500 FPS
Color space : YUV
Chroma subsampling : 4:2:0
Bit depth : 8 bits
Scan type : Progressive

[davexnet]

You could try adding this to a an mkv file and see if you can open it.
Download the mkvtoolnix package and install. One of the tools is called mkvmerge.

Open it and add this file, write it out as an mkv file and see if it opens in avidemux

[Rishtonite]

Thanks for the suggestion. I downloaded mkvtoolnix and read the mkvmerge documentation. Wow! Far to complex for my tiny brain.

[jagabo]

Wow! Far to complex for my tiny brain.

Use Mkvtoolnix-gui (it's included with the mkvtoolnix package). Drag the h264 file to the Source File window, press Start Multiplexing. You now have an MKV file that you can edit with AviDemux.

[Rishtonite]

Fantastic. Worked a treat. Very grateful for the suggestion/instruction.
Edited file 15Mb from original 1654Mb.