Project page: https://github.com/jellyfin/jellyfin-ffmpeg
Patches: https://github.com/jellyfin/jellyfin-ffmpeg/tree/jellyfin/debian/patches

Extract jellyfin-ffmpeg git repository
$ git clone https://github.com/jellyfin/jellyfin-ffmpeg.git
$ cd jellyfin-ffmpeg

Checkout the tag associated with current ffmpeg version
$ git tag --list | grep 7.1.4
$ git checkout v7.1.4-3

If there were deleted files from earlier manipulations
$ git restore .
$ git status
HEAD detached at v7.1.4-3
nothing to commit, working tree clean

Check that current ffmpeg matches jellyfin version
$ cat VERSION 
7.1.4

Modify patches to be in -p0 mode:
$ cd debian/patches
$ i=1001 && for p in *.patch; do \
    filterdiff -p1 --strip=1 "$p" > $(printf "%04d" $i)-jellyfin-$p ; \
    let i++ ; \
    done

Remove previous patches for spksrc repository:
$ cd ~/ffmpeg8/spksrc/cross/ffmpeg7/patches/
$ git rm 10*.patch

Copy new patches:
$ cp ~/jellyfin-ffmpeg/debian/patches/10*.patch .

Test the patches on a clean ffmpeg tree:
$ tar -jxvf ffmpeg-7.1.4.tar.bz2 
$ cd ffmpeg-7.1.4/
$ ls -1d ~/ffmpeg8/spksrc/cross/ffmpeg7/patches/*.patch | while read LINE; do patch -p0 < $LINE; done

Add them to spksrc repository:
$ git add 10*.patch
$ git add 10*.patch
$ git commit
