ffmpeg, add static image to beginning and end with transitions - ffmpeg

Question

ffmpeg noob here, trying to help my mother with some videos for real estate walkthroughs. I'd like to set up a simple pipeline that I can run videos through and have outputted as such:
5 second (silent) title card ->
xfade transition ->
property walk through ->
xfade transition ->
5 second (silent) title card
Considerations:
The intro / outro card will be the same content.
The input walkthrough videos will be of variable length so, if possible, a dynamic solution accounting for this would be ideal. If this requires me to script something using ffprobe, I can do that - just need to gain an understanding of the syntax and order of operations.
The video clip will come in with some audio already overlaid. I would like for the title cards to be silent, and have the video/audio clip fade in/out together.
I have gotten a sample working without the transitions:
ffmpeg -loop 1 -t 5 -i title_card.jpg \
-i walkthrough.MOV \
-f lavfi -t 0.1 -i anullsrc \
-filter_complex "[0][2][1:v][1:a][0][2]concat=n=3:v=1:a=1[v][a]" \
-map "[v]" -map "[a]" \
-vcodec libx265 \
-crf 18 \
-vsync 2 \
output_without_transitions.mp4
I have been unable to get it to work with transitions. See below for the latest iteration:
ffmpeg -loop 1 -t 5 -r 60 -i title_card.jpg \
-r 60 -i walkthrough.MOV \
-f lavfi -t 0.1 -i anullsrc \
-filter_complex \
"[0][1:v]xfade=transition=fade:duration=0.5:offset=4.5[v01]; \
[v01][0]xfade=transition=fade:duration=0.5:offset=12.8[v]" \
-map "[v]" \
-vcodec libx265 \
-crf 18 \
-vsync 2 \
output_with_transitions.mp4
This half-works, resulting in the initial title card, fading into the video, but the second title card never occurs. Note, I also removed any references to audio, in an effort to get the transitions alone to work.
I have been beating my head against the wall on this, so help would be appreciated :)

Answer 1

Assuming walkthrough.MOV is 10 seconds long:
ffmpeg -loop 1 -t 5 -framerate 30 -i title_card.jpg -i walkthrough.MOV -filter_complex "[0]settb=AVTB,split[begin][end];[1:v]settb=AVTB[main];[begin][main]xfade=transition=fade:duration=1:offset=4[xf];[xf][end]xfade=transition=fade:duration=1:offset=13,format=yuv420p[v];[1:a]adelay=4s:all=1,afade=t=in:start_time=4:duration=1,afade=t=out:start_time=13:duration=1,apad=pad_dur=4[a]" -map "[v]" -map "[a]" -c:v libx265 -crf 18 -movflags +faststart output.mp4
You will need to upgrade your ffmpeg for this to work. The current release version (4.3 as of this answer) is too old, so get a build from the git master branch. See FFmpeg Download for links to builds for your OS, or see FFmpeg Wiki: Compile Guide.
title_card.jpg frame rate, width, and height must match walkthrough.MOV.
See Merging multiple video files with ffmpeg and xfade filter to see how to calculate xfade and afade offsets.
See FFmpeg Filter documentation for details on each filter.
See How to get video duration in seconds? which can help you automate this via scripting.
apad is supposed to automatically work with -shortest, but it doesn't with -filter_complex. So pad_dur is used to add the additional silence to the last title image, but whole_dur can be used instead if that is easier for you. Another method is to use anullsrc as in your question, then concatenate audio only with the concat filter, but I wanted to show adelay+apad as a viable alternative.