ffmpeg5 fails to install with unmet dependencies

[Joy Bhattacherjee]

release Information:
```
Distributor ID: Ubuntu
Description: Ubuntu 20.04.4 LTS
Release: 20.04
Codename: focal
```

Steps followed:
```
  sudo add-apt-repository ppa:savoury1/ffmpeg4
  sudo add-apt-repository ppa:savoury1/ffmpeg5
  sudo apt-get update
  sudo apt-get upgrade && sudo apt-get dist-upgrade
  sudo apt-get install ffmpeg
```
output:
```
The following packages have unmet dependencies:
 ffmpeg : Depends: libavcodec59 (= 7:5.1-0ubuntu1~20.04.sav0)
          Depends: libavdevice59 (= 7:5.1-0ubuntu1~20.04.sav0) but it is not going to be installed
          Depends: libavfilter8 (= 7:5.1-0ubuntu1~20.04.sav0)
          Depends: libavformat59 (= 7:5.1-0ubuntu1~20.04.sav0)
E: Unable to correct problems, you have held broken packages.
```

tried installing deps manually
```
root@<host-ip>:~# sudo apt-get install ffmpeg libavcodec59=7:5.1-0ubuntu1~20.04.sav0 libavdevice59=7:5.1-0ubuntu1~20.04.sav0 libavfilter8=7:5.1-0ubuntu1~20.04.sav0 libavformat59=7:5.1-0ubuntu1~20.04.sav0 libjxl0.7
Reading package lists... Done
Building dependency tree
Reading state information... Done
Some packages could not be installed. This may mean that you have
requested an impossible situation or if you are using the unstable
distribution that some required packages have not yet been created
or been moved out of Incoming.
The following information may help to resolve the situation:

The following packages have unmet dependencies:
 libjxl0.7 : Depends: libhwy0 (>= 0.16.0) but it is not installable
```

breaks on an unavailable / unlisted pkg dependency.

I have also tried purging the PPA, autocleaning and reinstalling from scratch, no luck so far. Apologies if I have not given any pre-requisite information. Filing a launchpad bug after a while, bit rusty on the edges. let me know if I'm making any obvious mistake here.

[Rob Savoury (savoury1)]

Thanks for reporting this bug. It is due to me not remembering to copy across the highway package (from ppa:savoury1/backports) which is a dependency for jpeg-xl, and jpeg-xl is now a dependency of the new FFmpeg 5.1 (and 5.1+git) builds.

So just now I have copied the highway package to both ppa:savoury1/ffmpeg5 and ppa:savoury1/ffmpeg-git and it will be synced and available for download from Launchpad shortly. This should fix the install issue you have reported.

[Joy Bhattacherjee (joy-bhattacherjee)]

Thanks a lot for responding to the bug report Rob. We just tested out and the fix works. Highly obliged.