> On Nov 4, 2019, at 5:08 AM, Ha Viet <stev...@u2sr.com> wrote:
> 
> I am using your live555 library to transmitting h264 streams from my server 
> to clients.
> The server bases on OnDemandServerMediaSubsession and the client bases on 
> testRTSPClient.
> Both of them work pretty well except one thing is: I do not know the way to 
> make PTS of original 
> stream preserved through the transmission. 

Because of the way our server is implemented, you can’t do this.  Instead, the 
“fPresentationTime” values - used by our server when outputting data - must be 
aligned with ‘wall clock’ time (i.e., the time that you would get by calling 
“gettimeofday()”).

This does not mean that your server cannot use pre-recorded presentation time 
stamps.  You can do this; however, the *first* “fPresentationTime” must be 
aligned with the time that you’d get by calling “gettimeofday()”.  Thereafter, 
you can just add a constant offset to your prerecorded presentation time 
stamps.  I.e., in pseudo-code:

- For the first “fPresentationTime”:
        fPresentationTime = gettimeofday()
        const ptsOffset = fPresentationTime - prerecordedPresentationTime[0]
- For subsequent “fPresentationTimes”:
        fPresentationTime = prerecordedPresentationTime[N] + ptsOffset


Ross Finlayson
Live Networks, Inc.
http://www.live555.com/


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