ffplay: set stream_index to -1 earlier to prevent segfault

Signed-off-by: Peter Ross <pross@xvid.org>
Reviewed-by: Marton Balint <cus@passwd.hu>
(cherry picked from commit 6cfb33f976)

fftools/ffplay.c

@@ -2760,9 +2760,6 @@ static int read_thread(void *arg)
     }
 
     memset(st_index, -1, sizeof(st_index));
-    is->last_video_stream = is->video_stream = -1;
-    is->last_audio_stream = is->audio_stream = -1;
-    is->last_subtitle_stream = is->subtitle_stream = -1;
     is->eof = 0;
 
     ic = avformat_alloc_context();
@@ -3068,6 +3065,9 @@ static VideoState *stream_open(const char *filename, AVInputFormat *iformat)
     is = av_mallocz(sizeof(VideoState));
     if (!is)
         return NULL;
+    is->last_video_stream = is->video_stream = -1;
+    is->last_audio_stream = is->audio_stream = -1;
+    is->last_subtitle_stream = is->subtitle_stream = -1;
     is->filename = av_strdup(filename);
     if (!is->filename)
         goto fail;