Re: [MMUSIC] DECISION: Usage of same PT value in multiple m- lines for SAME codec configuration

[Paul Kyzivat <[e-mail]>]

On 6/28/13 12:41 PM, Emil Ivov wrote:
> On Fri, Jun 28, 2013 at 1:25 PM, Christer Holmberg
> <[e-mail]> wrote:
>
>> Q7: Within a BUNDLE group, do we allow the usage of the same PT value in
>> multiple RTP m- lines, for the SAME codec configuration?
>
> Generally yes.
>
>> Note: This of course prevents the mapping to m- line purely based on PT,
>
> You mean, only in case its actually used and not as a general BUNDLE
> rule, right?

I'm not sure I understand the distinction you are drawing.

The point is that when a packet with this PT is received, you won't be 
able to use the PT to determine which m-line in the bundle the packet 
should be associated with.

There must have been *some* reason that two m-lines were used, with the 
same PT, rather than just one. Each m-line heads a media section of the 
SDP that contains a bunch of declarations. Some of those are part of the 
payload description and so are the same. Something else must be 
different in those two media sections, or else a single media section 
would have been enough. Presumably whatever it is that is different is 
intended to affect how received packets are processed or interpreted. If 
you can't associate the packet with the m-line, then you don't know 
which of the multiple interpretations to apply to the packet.

	Thanks,
	Paul