[Asterisk-Dev] iax2 bridge optimization screwing with timestamps

[Andrew Kohlsmith]

On February 11, 2005 10:59 pm, Andrew Kohlsmith wrote:
> /* FIXME? SLD would rather remove this and leave it to the end system to
> deal with */
> if (fakets <= p2->lastsent)
>   fakets = p2->lastsent + 1;
> p2->lastsent = fakets;
>
> Now this isn't intuitive to me -- What exactly is this code fragment trying
> to do, and why on earth would you send it as the lastpacket+1 when it's
> supposed to be 20ms (or more generally, a codec frametime) later?

I love replying to myself.

I'm wondering if this may be a bug caused by p2->lastsent not taking into 
account whether the last sent packet was a "genuine" frame or not.  
calc_timestamp() goes to great pains to figure out whether a frame needs a 
clock-based or voiceframe-based timestamp but calc_fakestamp() does not do 
this.  If a genuine frame slipped in last and thus incorrectly set 
p2->lastsent, I *think* it could cause this kind of nastiness.

Not being an IAX2 expert though I am posting here to see how good my aim 
is.  :-)

-A.