[asterisk-dev] Meetme/Timing Basics

[Kevin P. Fleming]

Prakash Rao Kanthi wrote:

> Thanks Kevin. You said Zaptel does the mixing of SLINEAR data sent to
> it. Is it byte level mixing or RTP packet level mixing? And also i still
> have my questions on how the RTP from 2 users is streamed to 3rd user in
> the conference as a signle 64 Kbps channel without buffering.

Zaptel works on audio samples, it has no concept of frames. If you wish
to learn how the conference mixing works, read the source in zaptel.c

> Also can you point me to the code where incoming audio is converted to
> SLINEAR?

You said you were experienced with the Asterisk code :) Follow the path
through ast_set_read_format() and all the things it does, since you can
see that app_meetme.c sets the read format of the channel to SLINEAR
before adding it to the conference.