Transcode patch 1

[clinton-hall]

Description

Allow custom nice command handling.
Add logging of errors from ffmpeg to enable debugging.

Fixes #1619 1619

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)

How Has This Been Tested?

User tested.

Checklist:

• I have based this change on the nightly branch
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• New and existing unit tests pass locally with my changes

[clinton-hall]

Finally. I have CI working again (and it did catch a bug!)
Note:
https://developercommunity.visualstudio.com/content/problem/598264/known-issue-azure-pipelines-images-missing-sqlite3.html

This workaround can be removed at a later date (or potentially kept to force testing against a known python version).

Note the issue here was a broken sqlite installation within azure.