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

[Derk-Jan Hartman]

On 13 mei 2004, at 08:56, 袁瑞麟 Richard Yuan wrote:

> 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?
Open Source and according to the Specification?
I don't know of anything else atm that is as good as the liveMedia code.

> 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.

It means that VLC might not be able to handle the trick mode at a core 
level. It isn't called 'trick' mode for nothing. It's a trick and not 
really a part of the MPEG spec for instance. Therefore, it might be 
possible that VLC just won't know what to do with the data it receives 
in this mode. It's just never been tested, so you won't know how VLC 
will react. I suspect it will work, because VLC was originally designed 
to work with STB's, and those often support this. However, noone looked 
at this feature for a long time. Of that i'm sure.

> 3) Is there any other source code implement RTSP protocol? As a 
> joke,who
> is your competitor?
>
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----
Universiteit Twente
Derk-Jan Hartman (d.hartman at student.utwente dot nl)
http://home.student.utwente.nl/d.hartman