[Live-devel] RTSP - Absolute Time

[Erlandsson, Claes P (CERLANDS)]

After doing some testing with openRTSP and looking through the code it appears like "Absolute Time" is currently not supported for RTSP streams. I.e. I can't specify a specific time that the stream should seek to, e.g. Range: clock=20120629T070000.00Z, all according to paragraph 3.7 at http://www.ietf.org/rfc/rfc2326.txt.

I see some remarks for "clock" (and "smtpe") in the code at RTSPCommon->parseRangeParam() which sort of confirms that this is still to be done.

I'm curious if there is a reason that absolute time has been left out, i.e. are there problems implementing it, or is it just that people for some reason haven't been showing any interest in it?

I find the seek functionality to be an essential part of RTSP, but it's kind of hard to implement anything with just the npt-time (Normal Play Time) to use. For most uses, like Video Management Systems that uses a circular buffer, the start is a moving target, i.e. seeking to 50 minutes might not take you to the same place in 10 minutes as it does now.

Do you know of any reliable workarounds?

Thanks!


/Claes