ffplay: add a 3rd state to infbuf for autodetection

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

ffplay.c

@@ -278,7 +278,7 @@ static int exit_on_keydown;
 static int exit_on_mousedown;
 static int loop = 1;
 static int framedrop = -1;
-static int infinite_buffer = 0;
+static int infinite_buffer = -1;
 static enum ShowMode show_mode = SHOW_MODE_NONE;
 static const char *audio_codec_name;
 static const char *subtitle_codec_name;
@@ -2538,7 +2538,7 @@ static int read_thread(void *arg)
         }
 
         /* if the queue are full, no need to read more */
-        if (!infinite_buffer &&
+        if (infinite_buffer<1 &&
               (is->audioq.size + is->videoq.size + is->subtitleq.size > MAX_QUEUE_SIZE
             || (   (is->audioq   .nb_packets > MIN_FRAMES || is->audio_stream < 0 || is->audioq.abort_request)
                 && (is->videoq   .nb_packets > MIN_FRAMES || is->video_stream < 0 || is->videoq.abort_request)