Prevent spectrogram being selected as the poster.

[Borewit]

Related to:

• Improve poster selection: Try to select the front cover as the poster for audio/music torrents #1332,
• pull request Improve the poster selection for audio/music based torrent #1334

[Borewit]

Test torrent found on this page: Alvvays-Alvvays2014FLAC

Before:

After this change:

[feross]

Nice. Why does this need to be -80? Would 0 be sufficient?

[Borewit]

0 points would have no effect.
Prior to this change the 'spectrometer.jpg' would have got 0 points. 0 points are assigned to those images not matching any of the listed keyword / scores. So the assumption is that 0 point images are more likely to better choice for a poster then the spectrogram. Note that from these images, the largest will be selected.

The 0.8 * however is pointless, I will remove that one (was part of an unfinished attempt to balance a size score with a keyword score).

[Borewit]

Idea on additional improvement of the poster selection algorithm:

Taking the album name from the metadata, and inject this as a dynamic keyword, would definitely improve the poster selection in a lot of cases.

Relates to the metadata update lifecycle #1340.

[Borewit]

Thanks @ocheriaf !

[feross]

LGTM