fftools/ffmpeg: also flush encoders which have a variable frame size

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

fftools/ffmpeg.c

@@ -1915,9 +1915,6 @@ static void flush_encoders(void)
             }
         }
 
-        if (enc->codec_type == AVMEDIA_TYPE_AUDIO && enc->frame_size <= 1)
-            continue;
-
         if (enc->codec_type != AVMEDIA_TYPE_VIDEO && enc->codec_type != AVMEDIA_TYPE_AUDIO)
             continue;