[Live-devel] Get one frame at an absolute time

[Francisco Feijoo]

Hello Ross,

Thanks for pointing out the SMPTE Relative Timestamps concept. Looks like a
good thing to have in the future.

In any case, I don't know what should I do in any of the modes
(SMTPE/NPT/Absolute) when the server has sent the complete range specified
in the play command from the client. In RFC2326 I see this statement:

After playing the desired range, the presentation is automatically
paused, as if a PAUSE request had been issued.

How should I implement this in live555?

Thanks in advance.


2013/9/11 Ross Finlayson <finlayson at live555.com>

> I want to be able to request one single frame at an absolute time from the
> RTSP Client. Is that possible?
>
>
> The RTSP protocol specification has an optional mechanism that allows
> this: specifying a range that uses SMPTE-format times (that can address
> individual frames, by number).  However, the "LIVE555 Streaming Media" code
> does not support this, and it is unlikely to be added in the future (at
> least, not for free).
>
>
> In the server end, my own OnDemandServerMediaSubsession implements
> seekStreamSource and I pass absStart/absEnd to my own FramedSource.
>
> How should I implement my FramedSource doGetNextFrame so it only sends
> frames until the absEnd is reached (in this case only one frame).
>
>
> That's up to you to decide.  However, if your underlying data source uses
> a "ByteStreamFileSource" object, then note that the
> "ByteStreamFileSource ::seekToByteAbsolute()" function has an optional
> parameter "numBytesToStream".  If this parameter is non-zero, then our
> implementation of "ByteStreamFileSource" will automatically limit the
> stream to deliver that many bytes only, before treating it as EOF.  So, if
> you can figure out how many bytes you want to deliver, and are using a
> "ByteStreamFileSource", you can do it that way.
>
>
> Ross Finlayson
> Live Networks, Inc.
> http://www.live555.com/
>
>
> _______________________________________________
> live-devel mailing list
> live-devel at lists.live555.com
> http://lists.live555.com/mailman/listinfo/live-devel
>
>


-- 
Francisco Feijoo
Software Engineer
EyeLynx Limited

T: +44 020 8133 9388
E: francisco at eyelynx.com
W: www.eyelynx.com
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