Posted: Thu May 18, 2006 8:29 am Post subject: [Asterisk-video] Jitterbuffer
I never actually tried that, but if those are normal RTP packets it
should not be a difference with audio packets i think ?
Didnt you know somebody who claimed it broke video ? Could this person
tell us how he is using the video with asterisk ?
Joachim
Olle E Johansson wrote:
Quote:
As we have both Steve Kann and Zoa on the list : What about Video and
the IAX2 jitterbuffer and zoa's
new implementation?
Anyone that have tested?
/Olle
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Posted: Thu May 18, 2006 9:53 am Post subject: [Asterisk-video] Jitterbuffer
18 maj 2006 kl. 19.29 skrev Zoa:
Quote:
I never actually tried that, but if those are normal RTP packets it
should not be a difference with audio packets i think ?
Didnt you know somebody who claimed it broke video ? Could this
person tell us how he is using the video with asterisk ?
I don't remember, but we need to make sure that the jitterbuffer is
applied to both the audio rtp and the video rtp
streams. Those are different in rtp.c.
Any of you implementors out there on the list that can provide any
advice here? Do we need to sync with rtcp?
Any specific requirements for video jitterbuffers?
Posted: Thu May 18, 2006 9:53 am Post subject: [Asterisk-video] Jitterbuffer
The main difference with video is that you want to tread video frames
like control frames, and never drop them. -- If you're trying to shrink
the buffer, for example, while you'd throw away some audio to do that,
you'd want to just play video faster..
-SteveK
Zoa wrote:
Quote:
I never actually tried that, but if those are normal RTP packets it
should not be a difference with audio packets i think ?
Didnt you know somebody who claimed it broke video ? Could this person
tell us how he is using the video with asterisk ?
Joachim
Olle E Johansson wrote:
> As we have both Steve Kann and Zoa on the list : What about Video
> and the IAX2 jitterbuffer and zoa's
> new implementation?
>
> Anyone that have tested?
>
> /Olle
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> To UNSUBSCRIBE or update options visit:
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Posted: Thu May 18, 2006 9:54 am Post subject: [Asterisk-video] Jitterbuffer
If the jitterbuffer does any manipulation of the RTP data then it'll
break the video. The best it can do is just pass on the video packets.
Re-ordering out of sequence packets would be good though.
-----Original Message-----
From: asterisk-video-bounces@lists.digium.com
[mailto:asterisk-video-bounces@lists.digium.com] On Behalf Of Zoa
Sent: 18 May 2006 18:30
To: Discussion of video media support in Asterisk
Subject: Re: [Asterisk-video] Jitterbuffer
I never actually tried that, but if those are normal RTP packets it
should not be a difference with audio packets i think ?
Didnt you know somebody who claimed it broke video ? Could this person
tell us how he is using the video with asterisk ?
Joachim
Olle E Johansson wrote:
Quote:
As we have both Steve Kann and Zoa on the list : What about Video and
Quote:
the IAX2 jitterbuffer and zoa's
new implementation?
Anyone that have tested?
/Olle
_______________________________________________
--Bandwidth and Colocation provided by Easynews.com --
Posted: Thu May 18, 2006 9:57 am Post subject: [Asterisk-video] Jitterbuffer
Typically video is synced by using the SSRC of the two streams and the RTCP
reports that link a timestamp and a NTP time. From this, you can figure out
which packets corresponded to the same moment of time in each stream. In
practice though, usually it's possible to sync the video and the audio for a
real-time VoIP call without a great deal of effort, just by playing them
when they are received. This isn't always the case though, and the proper
way to do it is the way I mentioned above.
Also, depending on how the jitter buffer is written, it may not work for
video. I.e., the marker bit has a different meaning in video, so that may
break a jitter buffer written primarily for audio.
Duane
On 5/18/06, Olle E Johansson <oej@edvina.net> wrote:
Quote:
18 maj 2006 kl. 19.29 skrev Zoa:
>
> I never actually tried that, but if those are normal RTP packets it
> should not be a difference with audio packets i think ?
> Didnt you know somebody who claimed it broke video ? Could this
> person tell us how he is using the video with asterisk ?
I don't remember, but we need to make sure that the jitterbuffer is
applied to both the audio rtp and the video rtp
streams. Those are different in rtp.c.
Any of you implementors out there on the list that can provide any
advice here? Do we need to sync with rtcp?
Any specific requirements for video jitterbuffers?
/Olle
_______________________________________________
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Posted: Thu May 18, 2006 10:00 am Post subject: [Asterisk-video] Jitterbuffer
The only thing i could think of that could break things are the packet
loss handling, (replacing the lost frame with a zero frame).
Joachim
John Martin wrote:
Quote:
If the jitterbuffer does any manipulation of the RTP data then it'll
break the video. The best it can do is just pass on the video packets.
Re-ordering out of sequence packets would be good though.
-----Original Message-----
From: asterisk-video-bounces@lists.digium.com
[mailto:asterisk-video-bounces@lists.digium.com] On Behalf Of Zoa
Sent: 18 May 2006 18:30
To: Discussion of video media support in Asterisk
Subject: Re: [Asterisk-video] Jitterbuffer
I never actually tried that, but if those are normal RTP packets it
should not be a difference with audio packets i think ?
Didnt you know somebody who claimed it broke video ? Could this person
tell us how he is using the video with asterisk ?
Joachim
Olle E Johansson wrote:
>As we have both Steve Kann and Zoa on the list : What about Video and
>
>
>the IAX2 jitterbuffer and zoa's
>new implementation?
>
>Anyone that have tested?
>
>/Olle
>_______________________________________________
>--Bandwidth and Colocation provided by Easynews.com --
>
>asterisk-video mailing list
>To UNSUBSCRIBE or update options visit:
> http://lists.digium.com/mailman/listinfo/asterisk-video
>
>
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