adjust default video codec param,using cfr,frame rate 20 and key frame interval 100

@@ -66,7 +66,7 @@ cat   0.ts 1.ts 2.ts 3.ts 4.ts 5.ts 6.ts 7.ts 8.ts> m.ts ;linux
 ffmpeg -y -i m.ts -acodec copy -vcodec copy dest.ts
 
 
-调用ffmpeg时，视频编码参数是:  -vcodec libx264 -level 3.1 -preset veryfast -g 40 -r 20 
+调用ffmpeg时，视频编码参数是:  -vcodec libx264 -level 3.1 -preset veryfast -g 100 -r 20 -bf 0 -vsync cfr
 音频编码参数是： -acodec copy
 如果要修改，windows下在merge_av.exe同目录下新建merge_av.cfg文本文件，第一行保存视频编码，第二行保存音频编码;linux 下，merge_av.cfg保存在HOME目录下的merge_av目录。
 

@@ -69,7 +69,7 @@ void get_config_path(){
 #endif
 }
 
-const char * default_vcodec_param = "-vcodec libx264 -level 3.1 -preset veryfast -g 40 -r 20";
+const char * default_vcodec_param = "-vcodec libx264 -level 3.1 -preset veryfast -g 100 -r 20 -bf 0 -vsync cfr";
 const char * default_acodec_param = "-acodec copy";
 
 char vcodec_param[1024];
@@ -503,7 +503,7 @@ void load_codec_param()
 int main(int argc, char * argv[])
 {
 	if (argc < 2) {
-		printf("   merge_av 1.0.0\n");
+		printf("   merge_av 1.0.2\n");
 		printf("   run ffmpeg to merge audio and video files according to the record info file,\nusage:");
 		printf("\n   %s record_info_filename [-p] [-k]", argv[0]);
 		printf("\n   -p :only print the command,don't run ffmpeg");