I am developing an app. that will stream the video recorded from camera and stored as mp4 in sdcard...
I know there something called as RTSP which is used for that...
Please tell me where to start . .and is there any library that will do this for me...
I do not understand why you want to stream a local mp4 file, but maybe I misunderstood you problem. RTSP is used for live streaming, but you want to play a local mp4 file.
If you want to capture video and save it as mp4 onto a SD card, you need to use the Android MediaRecorder. Here a link to a simple example.
If you just want to playback a local mp4 file. Have a look at the Android API Demos.
These are part of the Android SDK installation and contain a good example of how to playback local media files.
https://github.com/Kickflip/kickflip-android-sdk does a similar job, but using HLS instead of RTSP.
We'r you able to solve your problem?