Investigate Retranscode Media functionality

[joelabreo227]

Transcoder offers a way to retranscode media:

However, the functionality seems to fail when re-retranscoding, useful in cases where media files are replaced or if a job fails:
Unfortunately, Transcoder failed to transcode this file (see above)

The status page confirms the failure:

To do:
Investigate why Transcoder fails in this case, perhaps related to the verification logic checking the presence of an immutable variable that's set the first time a file is transcoded.
Ideally, Transcoder should push through all retranscode requests, no questions asked.

A good place to start might be the logic behind the Check Status button:

[joelabreo227]

Potentially related issues:

• [VIP] [Retrancode All] Revisit the condition for retranscode all media #167
• Issue with transcoding the previously uploaded .m4a files #246
• Issue with re-transcoding the audio file #247

[dhaval-parekh]

While working on these issues, I found more problems when installing the Transcoder plugin in existing plugins.

• When we try to re-transcode the existing media. It shows there are no media that exists. Also, Markup is incorrect.

• The button to "Regenerate Thumbnail" is missing.