FFMPEG Error when downloading m4a files

[Timber1900]

Describe your bug At the moment using copy encoding for downloading audio files with WebDL causes a ffmpeg error. Current workaround is to select the correct audio enconding for the file extension used.

Describe steps to reproduce the bug

• Add a video to the queue
• Download audio with copy encoding

Propose a way to fix it Probably tie in the correct audio encoding for normal audio extensions (mp3, m4a, wav) or figure out why the copy encoding option isn't working (maybe missing metadata in audio stream)