[Live-devel] How can I implement the action(such as Backward or Forward) on RTSP client?

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First, thank you(Finlayson) very much for you reply,these are you said last
time: 
>To implement RTSP 'trick mode' operations (pause, seek, fast forward, 
>reverse play) in VLC, support for each operation needs to be present in 
>three places:
>
>1/ In the VLC module ("vlc/modules/demux/livedotcom.cpp") that implements 
>VLC's interface to the LIVE.COM RTSP client code.  (This code needs to 
>handle the corresponding VLC GUI operations that do each 'trick mode' 
>operation.)
>
>2/ The LIVE.COM RTSP client code ("RTSPClient").
>
>3/ The LIVE.COM RTSP server code - in particular, "RTSPServer", 
>"ServerMediaSubsession", and its hierarchical subclasses 
>"OnDemandServerMediaSubsession", "FileServerMediaSubsession" and 
>"<codecName>FileServerMediaSubsession".
>
>Looking at each of the 'trick mode' operations in turn:
>- Pause is implemented in 2/ and 3/, but not yet in 1/
>- Seek is implemented in 2/, but not yet in 1/ or 3/
>- Fast forward and reverse play are not yet implemented in 1/, 2/ or 3/.
>
>Of these tasks, the most difficult task would be to implement fast forward 
>and reverse play in 3/
Second, I want to know:
1) Is there any software implement these function between RTSP server/client?
2) Derk-Jan Hartman hartman at videolan.org said:
>I'm not sure if VLC is able to do this, there might be some core design 
>issue that would prevent it from supporting this.. I would consult 
>fenrir on the vlc-devel maillist as well, who originally wrote most 
>of the live.com code in VLC.
Does it mean that some core designs can't be revealed? It is very difficult
to implement.
3) Is there any other source code implement RTSP protocol? As a joke,who
is your competitor?