Only the first audio poster image is displayed (regression)

[bgreco]

Description

In a playlist of audio files, only, the first playlist item has its poster image displayed in the videojs player. All following items result in a black player.

Steps to reproduce

1. Create a playlist using an <audio> tag with with several audio files, each having a poster image.
2. Play the second playlist item.

Results

Expected

The player should display the second item's poster image.

Actual

No poster image is displayed.

Additional Information

This regression was introduced by #243.

Suggested resolution

Only hide poster images in video playlists. Do not hide poster images in audio playlists.

[rochapablo]

+1

[chipcullen]

FWIW, I'm seeing the same errant behavior with video playlists as well. Downgrading to 5.0.0 fixed the issue for me.