Add base knowledge of multimedia

README.md

@@ -8,15 +8,12 @@
 ### [音视频知识汇总](https://github.com/xufuji456/FFmpegAndroid/blob/master/doc/multimedia_knowledge.md)
 ### [ijkplayer播放器架构](https://github.com/xufuji456/FFmpegAndroid/blob/master/doc/player_framework.md)
 
+### 音视频基础知识:
+![preview](https://github.com/xufuji456/FFmpegAndroid/blob/master/picture/multimedia_baseline.png)
+
 ### Joining the group to learn FFmpeg:
 ![preview](https://github.com/xufuji456/FFmpegAndroid/blob/master/picture/ffmpeg_group.png)
 
 ### Joining QQ group to learn FFmpeg:
 ![preview](https://github.com/xufuji456/FFmpegAndroid/blob/master/picture/ffmpeg_qq.png)
 
-### 运行时序图:
-![preview](https://github.com/xufuji456/FFmpegAndroid/blob/master/picture/ffmpeg_sequence.png)
-
-### Preview thumbnail when seeking:
-![preview](https://github.com/xufuji456/FFmpegAndroid/blob/master/gif/preview.gif)
-