There is another location where transcoding can be disable in Device Settings, please go to 'Media Devices' and double-click your TV in the list (192.168.1.19) then on the Transcoding tab make sure the box to transcode incompatible formats is checked.

If Mezzmo is still delivering the original file to the TV because it matches the device profile you can force transcoding by going to the Advanced tab on the Device Settings dialog and change the setting for 'Deliver media files supported by the device' to 'Never Deliver' and then Mezzmo will transcode the files.

When files are added to the library from the Network Pane in Mezzmo the original URL provided by the host server (the HD Homerun) is sent to the device if the file format matches the device profile, so currently Mezzmo is listing the file for the Vizio TV with the URL for the HD Homerun and when the TV tries to play it the request is going to the HD Homerun and we cannot see any information about this exchange in the logs because the HD Homerun is handling the request. If Mezzmo transcodes the file then the Mezzmo server is requesting the content from the HD homerun then transcoding it and transferring the content to the TV so we should see more information about what is happening in the logs.