[Asterisk-video] confbridge, h264 and switching

Mon Apr 9 17:28:10 CDT 2012

Hi Matthew,

Checking one byte in first RTP packet of a frame shouldn't hurt the 
performance so badly.. ;)

Anyway, this is something that should be done in addition of requesting 
the update request in the INFO message.

Best regards
Sergio

El 09/04/2012 19:28, Matthew Jordan escribió:
> Sergio,
>
> If you have to retrieve information from the RTP packet and make some
> decision based on information within that packet - regardless of whether
> or not you have to fully decode the h.264 information contained within
> that packet - that's more then Asterisk currently does.
>
> There's a trade-off between performance and capability here, and
> performing logic on information in the media streams can quickly impact
> performance, particularly when you can't define the system your
> application will run on.
>
> That being said, this is a scenario that - in our testing - most SIP
> clients handle quite well with a request to update the picture.  If
> that's the only issue Dmitry is running into, its most likely best
> handled by the client, or determining why Asterisk is not sending
> the necessary SIP INFO message.
>
> If someone requires full media mixing, they're more then welcome to
> look at other products.
>
> Matthew Jordan
> Digium, Inc. | Software Developer
> 445 Jan Davis Drive NW - Huntsville, AL 35806 - USA
> Check us out at: http://digium.com&  http://asterisk.org
>
> ----- Original Message -----
>> From: "Sergio Garcia Murillo"<sergio.garcia at fontventa.com>
>> To: asterisk-video at lists.digium.com
>> Sent: Monday, April 9, 2012 10:15:08 AM
>> Subject: Re: [Asterisk-video] confbridge, h264 and switching
>>
>> Hi,
>>
>> I/P frame information can be retrieved from the h263/h264 stream
>> without
>> decoding it.
>>
>> Anyway, if you wan to try a full Multiconference server to integrate
>> with Asterisk, you can try mine.. ;)
>>
>> http://www.medooze.com/products/mcu.aspx
>>
>> Best regards
>> Sergio
>>
>> El 09/04/2012 16:34, Matthew Jordan escribió:
>>> ----- Original Message -----
>>>> From: "Dmitry Melekhov"<dm at belkam.com>
>>>> To: asterisk-video at lists.digium.com
>>>> Sent: Sunday, April 8, 2012 10:55:53 PM
>>>> Subject: Re: [Asterisk-video] confbridge, h264 and switching
>>>>
>>>> 06.04.2012 17:53, Matthew Jordan написал:
>>>>> Dmitry:
>>>>>
>>>>> Can you explain what you mean by "it brokes during switching"?
>>>> Hello!
>>>>
>>>> I mean that without i-frame talking user appears from squares and
>>>> other
>>>> strange shape still showing part of previous talker.
>>> <snip>
>>>
>>> Okay, now I understand what you're referring to.
>>>
>>> Yes, if the client that has been made the new video source does not
>>> transmit an I-Frame when they are made the video source, the
>>> receiving
>>> clients will predict their frames on the previously received frames
>>> from the previous video source.  That would lead to what you're
>>> describing.
>>>
>>> Since Asterisk does not interpret or decode the video streams it
>>> receives from the clients, it does not have a mechanism itself to
>>> manipulate the image.  It does, however, notify the client that is
>>> the new video source via a SIP INFO message that it is now the
>>> source
>>> of the video.  It is up to the client to know that it should then
>>> send
>>> an I-Frame to provide a reference point for the other clients for
>>> the
>>> new video images.
>>>
>>> A few questions then:
>>> 1. What clients are you using?  Do they support RFC 5168 (XML
>>> Schema
>>> for Media Control)?
>>> 2. If you get a SIP trace or a packet capture, do you see Asterisk
>>> sending the SIP INFO messages when a video update occurs?
>>>
>>> Thanks
>>>
>>> Matthew Jordan
>>> Digium, Inc. | Software Developer
>>> 445 Jan Davis Drive NW - Huntsville, AL 35806 - USA
>>> Check us out at: http://digium.com&   http://asterisk.org
>>>
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>>
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