Glimmerglass Festival releasing opera film for free on website The Glimmerglass Festival is releasing ‘The Knock’, a 50 minute opera as a film for free on its website on Veteran’s Day, Thursday, November 11. ‘The Knock’, composed by Aleksandra Vrebalov, was originally slated for a 2020 stage production, but after the pandemic hit, they decided to create the work as a film. The one-act opera is about the wives of military men waiting for news of their husbands. The libretto,…