Re: [Opalvoip-user] [opalvoip-user] Cannot decode H.264 from Polycom VVX 1500

[Denis L. <den...@go...>]

Hi Robert,

thank you for your clarification of this issue. We found out that the first
100 to 200 RTP packets of our H.264 media stream are always getting lost
due any reason we don't know so far. These packets were transmitted in the
first two packets in the stream, so this could be the reason that we cannot
decode the video.

We are currently investigating if we may support §8.4 principle 1 and 2 to
conceal these packet loss. Does opal support these principles? If not, what
is required to implement this feature?

Denis

2012/2/21 Robert Jongbloed <ro...@vo...>

> > -----Original Message-----
> > From: Denis Loh [mailto:den...@go...]
> > Sent: Wednesday, 22 February 2012 6:46 AM
> ....
> > Unfortunately, we cannot decode the H.264 stream of the polycom VVX. I
> > found the following log lines:
> ....
> >    2:52.566    Media Patch:0xb5eb8b70         dyna.cxx(211)
> >       FFMPEG  non-existing PPS 0 referenced
>
> This line usually indicates that the remote did not send the SPS/PPS
> packets
> at the beginning of the media stream. Well, it is rare for something to not
> send it at all, but what can happen is it gets lost. For example if the
> remote starts sending the video stream very early and the receiver is not
> yet ready, or there is a flood of packets sent at the start which overruns
> the receivers buffers.
>
> Who is calling who here?
>
> Can you please send both a Wireshark capture and the full trace log?
>
> ...
> > The decoder is still level 30. Is this correct?
>
> It does not matter what the decoder is set to. The remote sends the
> profile/level in the media stream and the decoder adjusts immediately. The
> values in the SDP and media formats are a MAXIMUM value, it can always be
> sent/received at a lower level.
>
> > We tried the same setup with a Polycom HDX 4xxx that supports level up
> > to 3.2. This works quite well. However, I don't know how to get the
> > VVX working.
> >
> > Is there a way to convince the h264 codec (in particular the decoder)
> > to use level 1.3? Maybe via a media option? I hope it's working then.
>
> See above.
>
>
> Partial logging information is rarely useful for debugging. Please send the
> full log file.
>
>
> Robert Jongbloed
> OPAL/OpenH323/PTLib Architect and Co-founder.
>
>
>
>
>
> ------------------------------------------------------------------------------
> Keep Your Developer Skills Current with LearnDevNow!
> The most comprehensive online learning library for Microsoft developers
> is just $99.99! Visual Studio, SharePoint, SQL - plus HTML5, CSS3, MVC3,
> Metro Style Apps, more. Free future releases when you subscribe now!
> http://p.sf.net/sfu/learndevnow-d2d
> _______________________________________________
> Opalvoip-user mailing list
> Opa...@li...
> https://lists.sourceforge.net/lists/listinfo/opalvoip-user
>