[Live-devel] RTSP: is random access possible on the server side?

[Shaswata Jash]

Hi Eric,

Just having a thought... Why several RTSP object ? The intelligence can
reside at the MediaSource level (more specifically file sources). That
intelligence in the source itself will decide from which part of media,
frames has to be fetched. This intelligence must depend on three factors :
chapter name, position of key video frame and a mapping of time with chapter
names. The suffix part (chapter name) of the RTSP URL can easily be sent to
the sources (through the constructor of the sources in
createNewStreamSource() functions of media sub session classes) as part of
file name. Though mapping of key frames with the time is not always present
explicitely (like in mpeg PS , you have to precalculate the mapping between
the I-frame with time where as for ISO base media file formats, this
information can be found directly from "stts" box).

With regards,
Shaswata

----- Original Message ----- 
From: <egf05 at doc.ic.ac.uk>
To: "LIVE555 Streaming Media - development & use"
<live-devel at ns.live555.com>
Sent: Monday, October 02, 2006 11:57 PM
Subject: Re: [Live-devel] RTSP: is random access possible on the server
side?


> Quoting Ross Finlayson <finlayson at live555.com>:
>
> >> Using VLC, there is a -start-time option that can be provided at
> >> the creation of the RTSP stream, however, this is very buggy
> >
> > It shouldn't be.  Specifying a start time in the RTSP "PLAY" command is
> > a well-established part of the protocol, and VLC's RTSP client
> > implementation supports this, I believe.  However, it's up to the
> > server to decide if and how to implement this.  As I noted in the link
> > above, it works for some media types only.
>
> Thank you very much for these infos.
>
> Actually, since I want the user to be able to start video at a
> specific time, by clicking on a single HTTP link (without using
> javascript) this should be implemented on the server side, as I cannot
> pass options to a client in a link (and I don't want to be client
> specific too). This should be entirely transparen to the user.
>
> Do you see any other way than having several RTSP/VoD objects for the
> same file, each one starting at the different times? Maybe in that
> case I should work on the VLC server code to add better support for
> the start time (which is certainly a harder work)?
>
> Regards,
> Eric
>
>
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