Avenged Sevenfold at War with Warner Bros. Over Greatest Hits Album

Avenged Sevenfold is going to war with Warner Bros. Records over a greatest hits album they don't think is so great ... because they never gave it their seal of approval.

The heavy metal band claims WBR released the album without notifying them, letting them select the songs or prepare the artwork -- a clear violation of their recording agreement ... according to a letter fired off to the company's CFO.

Avenged recently left WBR and signed with Capitol Records, then released a new album in October. A source close to the band tells us ... they believe WBR was pissed, so they rushed out a greatest hits album "in a fit of vindictiveness" to eat up the sales of their new record.

The band's demanding WBR pull "The Best of 2005-2013" from the shelves.

We reached out to Warner Bros. Records ... so far, no word back.