[BUG] Program exits with no warning when adding queue but forget adding audio content

[andrewschen]

1. load a file for encode
2. set audio processing as custom, and don't add anything in audio tab
3. click "generate" to create default output file name
4. click add queue, and program exits with no warning.
At step 3 if you manually input a file name then there will be a warning when you adding file with empty audio content to queue

[Selur]

Will look at it after Work.

Cu Selur