fftools/ffmpeg: Output log message when interactive q command is received

When viewing logs, it's sometimes useful to be able to see whether
execution was ended via q command.

Signed-off-by: softworkz <softworkz@hotmail.com>
Signed-off-by: Marton Balint <cus@passwd.hu>

fftools/ffmpeg.c

@@ -3991,8 +3991,10 @@ static int check_keyboard_interaction(int64_t cur_time)
         last_time = cur_time;
     }else
         key = -1;
-    if (key == 'q')
+    if (key == 'q') {
+        av_log(NULL, AV_LOG_INFO, "\n\n[q] command received. Exiting.\n\n");
         return AVERROR_EXIT;
+    }
     if (key == '+') av_log_set_level(av_log_get_level()+10);
     if (key == '-') av_log_set_level(av_log_get_level()-10);
     if (key == 's') qp_hist     ^= 1;