decoder: unblock picture allocation at exit

src/input/decoder.c

@@ -1761,6 +1761,16 @@ void input_DecoderDelete( decoder_t *p_dec )
     vlc_mutex_lock( &p_owner->lock );
     p_owner->b_waiting = false;
     vlc_cond_signal( &p_owner->wait_request );
+
+    /* If the video output is paused or slow, or if the picture pool size was
+     * under-estimated (e.g. greedy video filter, buggy decoder...), the
+     * the picture pool may be empty, and the decoder thread or any decoder
+     * module worker threads may be stuck waiting for free picture buffers.
+     *
+     * This unblocks the thread, allowing the decoder module to join all its
+     * worker threads (if any) and the decoder thread to terminate. */
+    if( p_owner->p_vout != NULL )
+        vout_Cancel( p_owner->p_vout );
     vlc_mutex_unlock( &p_owner->lock );
 
     vlc_join( p_owner->thread, NULL );