There are 2 possible solution to solve this problem. I have tested both on my Synolgy 916+ with DSM 6.1.3-15152 Update 4. They are both working but I suggest to use the first solution.

Install the FFmpeg package from the Synology community (reccomended)

Go to the “Package Center -> Settings -> Package Sources” and then click “add” to add a new source with the following details:

• Name: SynoCommunity
• Location: http://packages.synocommunity.com/

Click “OK” to save the settings and go to the “General” Tab to enable the installation of packages from any publisher:

Now go to the “Community” Tab, find the “ffmpeg” package and install it:

After the installation, click on it and check if it is running:

Done!

Install manually the FFpackage

This solution is just in case, that the first one is not working.

First of all you need to find out which Synology modell that you have (in my case 916+). You find it in the “System Settings -> Info-Center“:

Now, you need to find out which architecture that you need for the FFmpeg package. Go to “Architecture per Synology model” and search your model. In my case I have to use the braswell Architecture:

• DS916+ – synology_braswell_916+

Now that we know the architecure we can download the FFmpeg package from this site:

• https://mega.nz/#F!bF4TiIjK!O9AQKJiVoSrXpyBqrKCNRw
• Update 16.01.2018: this site has updated packages: https://guillaume.smaha.net/syno/
• Update 9.5.2019: official repository:  https://synocommunity.com/package/ffmpeg

In my case: “FFmpegWithDTS-braswell-1.0-0005.spk”

Now go to the “Package Center“, click on “Manual Installation” and select the previously downloaded FFmpeg package:

Select “next” and “apply“.

Congratulations! Now you should be able to run DTS videos 

Preparation

First of all you need to stop all the applications manually (open the application manager in the DSM). After this connect to your synology over SSH (enable it if not done yet).

Migration

Now we move all the applications from Volume 1 to the new Volume (in my case Volume 2):

mv /volume1/@appstore/* /volume2/@appstore/

Then we need to find out which applications have a link to the old volume:

find /var/packages/ -type l -ls | grep volume1

The output, depending on which applications you have installed, should look like this:

4480 0 lrwxrwxrwx 1 root root 34 Nov 4 18:39 /var/packages/DownloadStation/target -> /volume1/@appstore/DownloadStation

18333 0 lrwxrwxrwx 1 root root 28 Nov 4 18:39 /var/packages/VPNCenter/target -> /volume1/@appstore/VPNCenter

23299 0 lrwxrwxrwx 1 root root 28 Nov 4 18:40 /var/packages/DNSServer/target -> /volume1/@appstore/DNSServer

7021 0 lrwxrwxrwx 1 root root 31 Nov 4 18:39 /var/packages/VideoStation/target -> /volume1/@appstore/VideoStation

18325 0 lrwxrwxrwx 1 root root 30 Nov 4 18:40 /var/packages/MediaServer/target -> /volume1/@appstore/MediaServer

23973 0 lrwxrwxrwx 1 root root 31 Nov 4 18:41 /var/packages/CloudStation/target -> /volume1/@appstore/CloudStation

19596 0 lrwxrwxrwx 1 root root 28 Nov 4 18:41 /var/packages/AntiVirus/target -> /volume1/@appstore/AntiVirus

23175 0 lrwxrwxrwx 1 root root 34 Nov 4 18:38 /var/packages/StorageAnalyzer/target -> /volume1/@appstore/StorageAnalyzer

For each application you need to create a new simbolic link replacing the old one:

ln -sfn /volume2/@appstore/DownloadStation /var/packages/DownloadStation/target

ln -sfn /volume2/@appstore/VPNCenter /var/packages/VPNCenter/target

ln -sfn /volume2/@appstore/DNSServer /var/packages/DNSServer/target

ln -sfn /volume2/@appstore/VideoStation /var/packages/VideoStation/target

ln -sfn /volume2/@appstore/MediaServer /var/packages/MediaServer/target

ln -sfn /volume2/@appstore/CloudStation /var/packages/CloudStation/target

ln -sfn /volume2/@appstore/AntiVirus /var/packages/AntiVirus/target

ln -sfn /volume2/@appstore/StorageAnalyzer /var/packages/StorageAnalyzer/target

To be sure check that now the symbolic links are pointing to the new volume:

find /var/packages/ -type l -ls | grep volume2

4480 0 lrwxrwxrwx 1 root root 34 Nov 5 13:59 /var/packages/DownloadStation/target -> /volume2/@appstore/DownloadStation

6171 0 lrwxrwxrwx 1 root root 28 Nov 5 14:01 /var/packages/VPNCenter/target -> /volume2/@appstore/VPNCenter

17675 0 lrwxrwxrwx 1 root root 28 Nov 5 14:01 /var/packages/DNSServer/target -> /volume2/@appstore/DNSServer

7021 0 lrwxrwxrwx 1 root root 31 Nov 5 14:01 /var/packages/VideoStation/target -> /volume2/@appstore/VideoStation

17850 0 lrwxrwxrwx 1 root root 30 Nov 5 14:01 /var/packages/MediaServer/target -> /volume2/@appstore/MediaServer

17857 0 lrwxrwxrwx 1 root root 31 Nov 5 14:01 /var/packages/CloudStation/target -> /volume2/@appstore/CloudStation

17986 0 lrwxrwxrwx 1 root root 28 Nov 5 14:01 /var/packages/AntiVirus/target -> /volume2/@appstore/AntiVirus

18102 0 lrwxrwxrwx 1 root root 34 Nov 5 14:01 /var/packages/StorageAnalyzer/target -> /volume2/@appstore/StorageAnalyzer

Conclusion

The migration is done and you can start the applications again. They should work as normal