[FFmpeg-user] Extracting mp4 from a disk image

[John P]

I am attempting to extract all available mp4 files from an image of a drive
which was created by a Hikvision DVR.

If I use ffplay then it will start to play back recorded video, but can't
do much with it (I expect about 60 hours of video). There's lots of errors
on the console (illegal reordering etc) but it plays.

I tried using ffmpeg -err_detect ignore_err -i image.img -c copy output.mp4
but this just generated a large file with many hours of blank h264
1920x1080 video.

Is there some way to use ffmpeg to just extract all the video into a new
file, or files ?

thanks in advance
John