Calculate video total video length and output as total with respective folder

I'm working with some videos and I want to measure the total length of videos each folder contains and output it with the respective folder. Current structure is like this.

.
└── Parent folder/
    ├── Trip 1/
    │   ├── Video 1
    │   └── Video 2
    ├── Trip 2/
    │   ├── Video 3
    │   └── Video 4
    └── Trip 3/
        ├── Video 5
        └── Video 6

The output I'm trying to get is like this

Parent folder
  Trip 1 3h34m
  Trip 2 5h14m
  Trip 3 8h12m

So far I was able to get total of all 3 sub folders but I couldn't get it right to show it folder basis.

mediainfo '--Output=Video;%Duration%\n' *.mp4 | awk '{ sum += $1 } END { secs=sum/1000; h=int(secs/3600);m=int((secs-h*3600)/60);s=int(secs-h*3600-m*60); printf("%02d:%02d:%02d\n",h,m,s) }'

I'm open to use mediainfo or ffprobe packages or anything you suggest.

Your method is sound, you just need to nest it per folder.

find . -type d |while IFS= read dir; do
  t=$(mediainfo '--Output=Video;%Duration%\n' "$dir"/*.mp4 | awk '
    { sum += $1 }
    END {
      secs = int(sum / 1000 + 0.5);
      h = int(secs / 3600);
      m = int((secs - h * 3600) / 60);
      s = int(secs - h * 3600 - m * 60);
      printf("%02d:%02d:%02d\n", h, m, s)
    }') 2>/dev/null
  if [ "$t" != "00:00:00" ]; then
    echo "$dir: $t"
  fi
done \
  |sed -r 's:[^/]*/:--/:g; s:((--/)*)--/:\1-- :; s:--/:|   :g; s:([| ]*)-:\1|-:'

To adapt this to output hours and minutes as you requested in the question, change the printf statement to say printf "%dh%02.0fm", h, m + s/60 (this also rounds to the nearest minute).

I assume you already understand the mediainfo and awk commands since you supplied them, though I did change the millisecond conversion to be rounded. I've merely wrapped this in a find call that looks at all children directories of the current path (change . for another path) and loops through its output line by line (while IFS= read dir will read each line, even if there is spacing in it, into $dir. This will not work if you have linebreaks in your directory names).

Since the directory might not contain any .mp4 files, I've piped errors from the assignment to $t to /dev/null and then run a test to ensure the time isn't 00:00:00 (change that to 0h00m if you adapted the output). Then I print the directory and the time.

Finally, a sed uses extended regular expressions (-r) to convert this into a tree with four substitutions (s):

1. Convert each parent directory name to two dashes (keep the trailing slash for now)
2. Remove the final trailing slash
3. Any parent remaining should get a pipe and spaces
4. Add interim pipes