Update README.MD

ffmpeg/README.MD

@@ -15,5 +15,13 @@ ffprobe -v error -show_entries format=bit_rate -of default=noprint_wrappers=1:no
 
 # 视频文件切片
 ```
+# 平均码率转换
+ffmpeg -i <File> -vcodec copy -acodec aac -bsf:v h264_mp4toannexb -b:v 2000k -bufsize 2000k -maxrate 2500k output.mp4
+# 切片
+ffmpeg -i output.mp4 -vcodec copy -acodec copy -map 0 -f segment -segment_list output.m3u8 -segment_time 10 output_%03d.ts
+```
+
+# 视频文件直接切片
+```
 ffmpeg -i <File> -vcodec copy -acodec aac -bsf:v h264_mp4toannexb -map 0 -f segment -segment_list output.m3u8 -segment_time 10 output_%03d.ts
 ```