[Ffmpeg-devel] [PATCH] fix ffmpeg crash when thread_count is zero

[Limin Wang]

Hi,

After inputing "-threads auto" option for ffmpeg as x264, mencode by mistaken.
I got ffmpeg crashed. After checking, I got the reason is ffmpeg get
thread_count to zero in case of this usage. 

The attached patch will check and restrict the thread_count range from 1 to
FF_THREAD_MAX. Maybe it's better to support auto option like x264?


Thanks,
Limin
-------------- next part --------------
Index: ffmpeg.c
===================================================================
--- ffmpeg.c	(revision 8140)
+++ ffmpeg.c	(working copy)
@@ -2323,6 +2323,8 @@
 static void opt_thread_count(const char *arg)
 {
     thread_count= atoi(arg);
+
+    thread_count = av_clip( thread_count, 1, FF_THREAD_MAX );
 #if !defined(HAVE_THREADS)
     if (verbose >= 0)
         fprintf(stderr, "Warning: not compiled with thread support, using thread emulation\n");
Index: libavutil/common.h
===================================================================
--- libavutil/common.h	(revision 8140)
+++ libavutil/common.h	(working copy)
@@ -75,6 +75,8 @@
 
 #define FFSWAP(type,a,b) do{type SWAP_tmp= b; b= a; a= SWAP_tmp;}while(0)
 
+#define FF_THREAD_MAX 16
+
 /* misc math functions */
 extern const uint8_t ff_log2_tab[256];