if ffmpeg -i .name.ass fails, then rm .name.ass

src/asses/deport.go

@@ -56,6 +56,10 @@ func deport(ctx context.Context, p string) error {
 		}
 
 		if err := ffmpeg(ctx, "-y", "-i", ass, srt); err != nil {
+			if ctx.Err() == nil {
+				log.Printf("ffmpeg failed to process %s; removing", ass)
+				os.Remove(ass)
+			}
 			return err
 		}